Oligocene Molluscan Biostratigraphy and 

Paleontology of the Lower Part of the 

Type Temblor Formation, California

GEOLOGICAL SURVEY PROFESSIONAL PAPER 791
Oligocene Molluscan Biostratigraphy and 

Paleontology of the Lower Part of the 

Type Temblor Formation, California

By WARREN O. ADDICOTT

GEOLOGICAL SURVEY PROFESSIONAL PAPER 791

Marine mollusks from the basal shale (Cymric Shale Member) 

and the overlying sandstone (Wygal Sandstone Member) are 

of provincial Oligocene age. Warm-water assemblages from 

the Wygal Sandstone Member represent a previously 

unrecognized biostratigraphic unit of late 

Oligocene age in California

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY

V. E. McKelvey, Director

Library of Congress catalog-card No. 72-600377

For sale by the Superintendent of Documents, U.S. Government Printing OfBce, Washington, D.C. 20402 

Price: paper cover-$1.25, domestic postpaid; $1.00, GPO Bookstore Stock No. 2401-00284
CONTENTS

Abstract ___________________________ 

Introduction _________________________

Acknowledgments _____ _________________

Reports dealing with mollusks from the lower part 

of the Temblor Formation ______________________

Stratigraphy ____________________________

Wygal Sandstone Member __________________

Provincial age and correlation ____________________

General considerations ________________

Cymric Shale Member ________________________

Wygal Sandstone Member ____________________

Santos Shale Member ________________________

Agua Sandstone Member _____________

Paleobathymetry _________________________________

Zoogeography and paleoclimatology _______________

Systematic descriptions ___________________________

Class Gastropoda ____________________________

Order Archaeogastropoda ______________

Family Trochidae ___________________

Order Mesogastropoda ___________________

Family Cerithiidae? __________________

Family Calyptraeidae __-___________

Family Naticidae _______________

Family Ficidae _______________ 

Order Neogastropoda ____________

Family Neptuneidae __________________

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Systematic descriptions Continued 

Class Pelecypoda _____________

Order Nuculoida _________

Family Nuculidae ____

Family Nuculanidae __ 

Order Arcoida ___ ____

Family Arcidae ______

Order Mytiloida _________

Family Mytilidae 

Order Pterioida _________

Family Pectinidae 

Family Ostreidae ____

Order Veneroida _________

Family Lucinidae __ 

Family Ungulinidae _ 

Family Mactridae 

Family Solenidae ____

Family Tellinidae ____

Family Veneridae ____

Order Myoida ___________

Family Myidae ______

Class Scaphopoda __________

Family Dentaliidae 

Fossil localities __ ______________

References _ _________________

Index ____________________

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ILLUSTRATIONS

	[Plates 1-9 follow index]

PLATE 1. Acila, Anadara, Crenomytilust, Leptopecten, Vertipecten, Yoldia.

2. Crassostrea, Lucinoma, Pecten, Vertipecten.

3. Crenomytilusl, Here, Lucinoma, Miltha, Vertipecten.

4. Crenomytilus, Felaniella, Solen, Spisula, Tellina, Tellinal.

5. Heteromacoma, Mac/oma, Pseudocardiumt, Tellina.

6. Amiantis, Dosinia, Heteromacoma, Pitar, Securella, Tellina.

7. Amiantis, dementia, Dosinia.

8. Calyptraea, cerithiid?, dementia, Crepidula, Dentalium, Natica, Panopea, Tegula.

9. Bruclarkia, Calicantharus, Ficus, Kelletial, NeDerita, Polinices, Sinum, Siphonaliat.

FIGURE 1. Index map showing location of Temblor Range _____________________________________

2. Stratigraphic nomenclature of the type Temblor Formation, Temblor Range, Kern County, Calif _

3. Geologic index map showing distribution of the Temblor Formation, central Temblor Range, Kern 

	County, Calif __________________________________________________________________________

4. Molluscan and foraminiferal provincial stage classification of the type Temblor Formation ____

5. Zoogeographic profiles for selected Tertiary faunal assemblages from the San Joaquin basin, California _

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TABLES

TABLE 1. Systematic list of mollusks from the Wygal Sandstone Member of the Temblor Formation, Temblor 

Range, Calif _________________________________________________________________________

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III
IV CONTENTS

Page

TABLE 2. Chart showing specifically determined mollusks from the Wygal Sandstone Member of the Temblor Formation __________________ 11

3. Chart showing ranges of some species of Bruclarkia and Vertipecten _____________________________ 12

4. Molluscan species from the Wygal Sandstone Member that are not known to occur in strata of Refugian

age 12

5. Molluscan genera and subgenera from the Wygal Sandstone Member that are not known to occur in

strata of Refugian age __ ___________ _ 13

6. Mollusks from the Agua Sandstone Member of the Temblor Formation __ ___ ___ __________ 14
OLIGOCENE MOLLUSCAN BIOSTRATIGRAPHY AND

PALEONTOLOGY OF THE LOWER PART OF THE TYPE

TEMBLOR FORMATION, CALIFORNIA

By WARREN O. ADDICOTT

ABSTRACT

The type Temblor Formation consists of about 1,800 feet 

of alternating shale and sandstone units exposed in the 

central part of the Temblor Range along the southwest 

margin of the San Joaquin Valley in central California. 

The lower part constitutes a unique stratigraphic continuum 

of marine middle Tertiary strata in the California Coast 

Ranges. Molluscan stages of provincial late Oligocene and 

early Miocene age can be recognized on the basis of assemblages from the lowest sandstone members of the formation. 

These units are directly associated with deeper water foraminiferal assemblages that constitute the type section of the 

Zemorrian Stage of the provincial microfaunal sequence. 

Elsewhere in central and southern California, the Oligocene 

and the earliest part of the Miocene are usually represented 

by nonmarine deposition.

A small assemblage from the Cymric Shale Member at 

the base of the Temblor Formation contains Bruclarkia 

columbiana (Anderson and Martin), the presence of which 

suggests correlation with the upper part of the Refugian 

Stage [="Lincoln Stage" of western Washington]. The 

Cymric Shale Member was originally included in the lower 

part of the overlying Zemorrian Stage of the microfaunal 

chronology based on meager foraminiferal data.

Assemblages from the overlying Wygal Sandstone Member comprise a biostratigraphic unit of provincial late 

Oligocene age that had previously been assigned to the 

early Miocene "Vaqueros Stage." Included in this fauna are 

the stratigraphically restricted species Pecten sanctaecruzensis Arnold, Bruclarkia seattlensis Durham, and Vertipecten alexclarki n. sp. This fauna is correlated with the 

lower part of the Zemorrian Stage of the microfaunal 

chronology.

The stratigraphically higher Agua Sandstone Member 

contains small assemblages referable to the early Miocene 

"Vaqueros Stage." Included are the stratigraphically restricted species Crassostrea vaquerosensis (Loel and Corey) 

and Macrochlamis magnolia (Conrad). This member is correlated with the upper part of the Zemorrian Stage.

The molluscan fauna of the Wygal Sandstone Member is 

indicative of a warm, shallow-water depositional environment less than 20 fathoms and possibly much shallower at 

the base. Many of these genera are today restricted to subtropical and tropical latitudes along the Pacific coast of 

Mexico and Central America. The hermatypic coral Favites 

provides further evidence of warm-water conditions. Yet, 

this inner sublittoral biofacies contrasts with the middle to

lower bathyal environments inferred from benthonic foraminiferal assemblages of the underlying Cymric Shale 

Member and the overlying Santos Shale Member.

Fifty mollusks, almost all of them previously unrecorded 

from the Wygal Sandstone Member, are treated systematically. Six of these represent new species, although only one, 

Vertipecten alexclarki n. sp., is represented by material 

adequate to permit formal description. A new tellinid subgenus, Olcesia (type: Macoma piercei Arnold), has its lowest stratigraphic occurrence in assemblages from the Wygal 

Sandstone Member.

INTRODUCTION

The type area of the Temblor Formation is in the 

central part of the Temblor Range near the western 

margin of the San Joaquin basin about 40 miles 

west of Bakersfield, Calif, (fig. 1). In this area the 

Temblor Formation consists of alternating shale 

and sandstone totaling about 1,800 feet in thickness 

(Woodring and others, 1940).

The most definitive biostratigraphic study of the 

type Temblor Formation (Kleinpell, 1938) was 

based on benthonic Foraminifera. In that report, 

and in an earlier one (Kleinpell, 1934), he showed 

that the lower part of the type Temblor Formation 

was of pre-middle Miocene age. Prior to Kleinpell's 

studies most workers regarded the Temblor Formation to be wholly of middle Miocene age and to be 

referable to what later became known as the "Temblor Zone" (Clark, 1941) or "Temblor Stage" 

(Weaver and others, 1944; Durham, 1954). Kleinpell's (1938) data were substantiated in a brief 

biostratigraphic analysis of known molluscan assemblages from the vicinity of the type Temblor 

Formation by Woodring, Stewart, and Richards 

(1940, p. 131), who concluded that the lower part 

of the type Temblor Formation is "of the age of 

the Vaqueros elsewhere" [early Miocene].

The molluscan faunas of the type Temblor Formation and its lateral correlatives in the northern 

part of the Temblor Range have received only cursory study. The largest recorded faunal list prior
MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

35 e

120 £

20 MILES

119°

FIGURE 1. Location of the Temblor Range.

to this study (Anderson, 1905, p. 170), for example, 

is from the Wygal Sandstone Member, but it includes only 11 mollusks in contrast to the 50 molluscan taxa treated in this report. The lack of intensive paleontologlc and biostratigraphic study of 

the Temblor Formation may result from the fact 

that in the type area all the sandstone members except the lowest one, the so-called Phacoides Sand 

[Wygal Sandstone Member of this report], have 

sparse assemblages of larger marine invertebrates. 

Nevertheless, collections at hand from the type area 

in the central part of the Temblor Range and from 

more fossiliferous exposures in the northern part 

of the range are adequate to establish a local biostratigraphic sequence. Although this report is primarily concerned with the Wygal Sandstone Member, the sequence of Oligocene and early Miocene 

molluscan faunas of the Temblor Range is briefly

outlined and correlated with the established provincial molluscan stages of Weaver and others 

(1944) and with the benthonic foraminiferal stages 

of Kleinpell (1938) and Schenck and Kleinpell 

(1936). The conclusions of this report differ from 

those of earlier workers in that at least one, and 

possibly two, Oligocene biostratigraphic units of 

stage magnitude are represented in the lower part 

of the type Temblor Formation. The next to the 

lowest of these two units, which is represented by 

the fauna of the Wygal Sandstone Member, is the 

subject of this report. Molluscan data from the 

underlying Cymric Shale Member and from the 

overlying Santos Shale and Agua Sandstone Members are considered in a following section on provincial age and correlation in order to establish the 

limits of the late Oligocene biostratigraphic unit 

represented by the Wygal fauna.
ANNOTATED REFERENCES TO THE MOLLUSCAN FAUNA

ACKNOWLEDGMENTS

Several people provided helpful assistance during 

the course of this study. The manuscript has been 

critically read by E. E. Brabb, T. W. Dibblee, Jr., 

E. J. Moore, and R. L. Pierce. Their comments and 

suggestions have improved the report and are 

deeply appreciated. Dibblee mapped the geology in 

this report and discussed stratigraphic relationships 

and formational nomenclature. Olgerts Karklins, 

U.S. Geological Survey, and Alan H. Cheetam, 

U.S. National Museum, kindly identified an encrusting bryozoan, and J. Wyatt Durham, University of California, Berkeley, identified the 

corals. Dibblee, Saburo Kanno, R. L. Pierce, H. 

S. Sonneman, and H. C. Wagner assisted in 

making some of the mega-invertebrate collections 

from the Wygal Sandstone Member. J. G. Vedder 

collected mollusks from the Quail Canyon Sandstone 

Member of the Vaqueros Formation (Dibblee, 1972) 

to which this report refers. M. A. Murphy, University of California, Riverside, granted access to 

museum collections and lent specimens for figuring 

in this report. A. M. Keen and N. J. Silberling, 

Stanford University, and J. H. Peck, Jr., University 

of California, Berkeley, also granted access to museum collections and type collections at their respective institutions. R. L. Pierce and C. C. Church, 

Bakersfield, Calif., discussed problems of foraminiferal correlation with the writer. Fossil photography is by Kenji Sakamoto.

I am particularly indebted to H. S. Sonneman, 

who initially suggested the biostratigraphic study 

of mollusks from the type Temblor Formation and 

who collaborated during much of the fieldwork and 

preparation of this report.

REPORTS DEALING WITH MOLLUSKS FROM

THE LOWER PART OF THE

TEMBLOR FORMATION

Annotated references to the molluscan fauna of 

the Wygal Sandstone Member are listed chronologically in this section. Stratal terminology and fossil 

names indicated in the annotations are those of the 

authors cited. Place names are indicated in figure 3. 

Complete bibliographic citations are included in 

the references at the end of the report.

1905. Anderson, F. M. Designated the area between Carnara Spring [Carneros Creek] and Temblor [Temblor Ranch], to the south, as the type area for 

his Temblor Beds. Seven species and four genera 

of mollusks are listed from his lower sandstones. 

This is the most complete published faunal list 

from the Wygal Sandstone Member of the Temblor 

Formation.

1910. Arnold, Ralph, and Johnson, H. R. The basal 25 ft of 

a 445-ft measured section of the Vaqueros Sandstone [Temblor Formation] between Salt Creek 

and Temblor Creek (W% sec. 25, T. 29 S., R. 20 

E.) contains Ostrea and many indeterminate, 

poorly preserved fossils. A collection from between 

Chico Martinez and Carneros Creeks (USGS 5149) 

made during fieldwork for this report was not recorded. Species from this locality are listed in 

table 1.

1921. English, W. A. Four measured sections of the Vaqueros Formation [Temblor Formation] between 

Salt and Media Agua Creeks are included in a 

correlation diagram. The basal sandstone beds contain a large [molluscan] fauna, best developed 

near Carneros Spring and Media Agua Creek.

1936. Hanna, G D. Abundant Phacoides acutilineatus occur 

in the basal part of Anderson's (1905) Temblor 

Formation. The jaw of a small-toothed whale, a 

zeuglodont, is reported from these strata.

1936. Schenck, H. G. Reported specimens of Acila conradi 

(Meek) var. from beds of "Vaqueros" age on the 

southwest flank of McDonald anticline (sec. 31, 

T. 27 S., R. 19 E.). The associated molluscan assemblage was regarded by Alex Clark as correlative with the lower sandstone member of the 

Temblor Formation on Carneros Creek [Wygal 

Sandstone Member], although it contains species 

such as Bruclarkia barkeriana and Chione cf. C. 

panzana that are indicative of a Miocene rather 

than Oligocene provincial age. The fossil locality 

is probably from near the base of the Buttonbed 

Sandstone Member, which unconformably overlies 

the Eocene Point of Rocks Formation in this area. 

A recent collection from the basal 5 ft of this unit 

(USGS loc. M3988) contains Trophosycon kernianum, Oliva California, Amussiopecten sp., and 

Lyropecten crassicardo, fossils suggestive of a 

middle Miocene ("Temblor") provincial age.

1938. Kleinpell, R. M. Four molluscan taxa including 

Chlamys sespeensis in the Phacoides reef [Wygal 

Sandstone Member] and Bruclarkia barkeriana 

[B. seattlensis] are recorded from localities in the 

Zemorra Creek-Chico Martinez Creek area. This 

assemblage occurs in the lower part of his Zemorrian Stage and was correlated with the Turritella 

inezana zone.

1940. Woodring, W. P., Stewart, Ralph, and Richards, 

R. W. Abundant Lucinoma acutilineata occur in 

their "Phacoides" reef member of local usage 

[Wygal Sandstone Member] near the base of a 

measured section of the type Temblor Formation 

on Zemorra Creek. Typical "Vaqueros Stage" species are not known to occur in this member, although the faunal fades is such that they might 

be expected to occur in it. "Vaqueros Stage" index 

species occur in stratigraphically higher units in 

this part of the Temblor Range.

1943. Curran, J. F. Six mollusks are listed from the "reef" 

[Wygal Sandstone Member] at the base of his 

lower Temblor Sandstone in the vicinity of Chico 

Martinez Creek.

1959. Stinemeyer, E. S., Beck, R. S., Ortalda, R. A., Espenscheid, E. K., Bainton, J. D., and O'Keefe, M. S.
MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

Exposures of the basal part of the Phacoides Sand 

[Wygal Sandstone Member] on Zemorra Creek 

contain Lucina acutilineata [Lucinoma acutilineata], Pecten branneri [Vertipecten alexclarki n. 

sp.], Ostrea sp., and Bruclarkia barkeriana [B. 

seattlensis],

1963. Kleinpell, R. M., and Weaver, D. W. The molluskbearing lower ("Phacoides Reef") sandstone member of the Temblor Formation [Wygal Sandstone 

Member] is correlated with the middle sandstones 

of the type Alegria Formation of the Santa Barbara embayment and with their Soda Lake Sandstone of the Cuyama Valley area, eastern San 

Luis Obispo County.

1968. Elliott, W. J., Tripp, Eugene, and Karp, S. E. Lucina 

acutilineatus [Lucinoma acutilineata] is the pelecypod for which the Phacoides Sand [Wygal Sandstone Member] was named.

1968. Foss, C. D., and Blaisdell, Robert. Their "Phacoides 

Sand" member [Wygal Sandstone Member] of the 

Temblor Formation contains mollusks alleged to 

be referable to the Turritella inezana zone; seven 

species are listed. This member is unconformably 

overlain by their "Lower" Santos Shale Member 

of the Temblor Formation.

1969. Addicott, W. 0. About 35 percent of the still-living 

molluscan genera from the so-called Phacoides 

sandstone [Wygal Sandstone Member] are today 

restricted to warm-water latitudes of the eastern 

North Pacific.

1970b. Addicott, W. 0. Faunal data presented in Addicott 

(1969) are tabulated. Thirty-one molluscan genera 

occur in the so-called "Phacoides" reef [Wygal 

Sandstone Member]. The fauna is of much warmer 

water aspect than that of the subjacent Refugian 

Stage of the San Joaquin basin.

1970. Mallory, V. S. The "Lower Temblor sandstone" 

[Wygal Sandstone Member] unconformably overlies Eocene sandstone at Media Agua Creek. Three 

mollusks including Lucinoma acutilineata are 

listed.

1970c. Addicott, W. 0. A significant increase in the percentage of molluscan genera of tropical and subtropical affinities occurred during the late Oligocene in the San Joaquin basin. The increase is 

based on comparison of the middle Oligocene fauna 

of the Acila shumardi Zone of the San Emigdio 

Mountains with the fauna of the so-called "Phacoides" sandstone [Wygal Sandstone Member] of 

the type Temblor Formation.

1972. Addicott, W. 0. Mollusks from the Phacoides Sand 

Member of Stinemeyer and others (1959) are of 

post-Refugian and pre-"Vaqueros" age. This 

fauna is believed to represent a previously unrecognized stage in California and is coeval with the 

lower part of the "Blakely Stage" of western 

Washington. This summary report was written 

after the present paper was completed; the sections 

in it dealing with the lower part of the type Temblor Formation are summarized from this report.

1973. Addicott,W. 0. The fauna of the so-called "Phacoides 

reef," formerly assigned to the "Vaqueros Stage," 

represents a previously unrecognized post-

"Lincoln," pre-"Vaqueros" molluscan stage in 

California.

STRATIGRAPHY

The Temblor Formation was named (as Temblor 

Beds) by Anderson (1905) for exposures between 

Temblor Ranch and Carneros Creek in the central 

part of the Temblor Range about 15 miles northwest of McKittrick, Calif. The base of the formation is marked by an unconformity with the underlying Point of Rocks Sandstone of Eocene age; the 

top, by a conformable contact with the Monterey 

Shale. The Temblor Formation consists of several 

shale and sandstone units totaling about 1,800 feet 

in thickness in the type area (Woodring and others, 

1940, p. 130). These units have been given informal 

names in the course of petroleum exploration and 

development in oil fields bordering the eastern flank 

of the Temblor Range (Cunningham and Barbat, 

1932; Gester and Galloway, 1933; Goudkoff, 1941), 

and these names have been summarized in many 

publications (Woodring and others, 1940; Weaver 

and others, 1944; Stinemeyer and others, 1959; Foss 

and Blaisdell, 1968). A comparison between earlier 

stratigraphic nomenclature and that for the members of the Temblor Formation formally named and 

described by Dibblee (1973) is shown in figure 2.

Formation

Formation Temblor 

Member

Earlier usage (Stinemeyer and others, 1959)

Buttonbed Sand

Media Shale

Carneros Sand

Upper Santos Shale

"Agua Sand" interval

Lower Santos Shale

Phacoides Sand

Salt Creek Shale

Dibblee (1973) and this 

report

Buttonbed Sandstone

Media Shale

Carneros Sandstone

Santos Shale

Agua Sandstone

Santos Shale

Wygal Sandstone

Cymric Shale

FIGURE 2. Stratigraphic nomenclature of the type Temblor 

Formation, Temblor Range, Kern County, Calif.

WYGAL SANDSTONE MEMBER

The Wygal Sandstone Member of the Temblor 

was named by Dibblee (1973) for exposures on 

Chico Martinez Creek in the central part of the 

Temblor Range about 8 miles southwest of South 

Belridge oil field. This unit was previously known 

by the informal local name Phacoides sand, or Phacoides reef, following Kleinpell (1938, p. 107). The 

informal name Phacoides was based on the abundant articulated valves of the mollusk Lucinoma 

acutilineata that characterizes this unit throughout
WYGAL SANDSTONE MEMBEE

its surface exposure. The Wygal crops out in a folded 

but generally northeast-dipping marine sequence 

extending over a 12-mile area from the west fork 

of Devilwater Creek on the northwest (Glover, 

1953) to Temblor Creek on the southeast (fig. 3). 

This sandstone member is 3 or 4 feet thick on the 

north side of Media Agua Creek (USGS loc. M4473)

near its northwestern limit and increases to as much 

as 85 feet on Zemorra Creek (Woodring and others, 

1940). Throughout most of the area, however, the 

fossiliferous part of the member ranges from 20 to 

40 feet in thickness. In the thicker sections, there 

there are usually three or four pelecypod-bearing, 

calcareous sandstone beds that average about 2 feet

35°30'-

Antelope Hills 

oil field

McDonald Anticline 

oil field

South 

Belridge 

oil field

EXPLANATION 

Temblor Formation

Synclinal fold 

Fossil localities

M3772 

X 5159

U.S. Geological Survey, 

Wygal Sandstone Member

+ UCR 1235

California Univ., Riverside, 

Wygal Sandstone Member

0UCR 1106

California Univ., Riverside, 

Cymric Shale Member

Temblor Ranch

5 MILES

119°45'

FIGURE 3. Distribution of the Temblor Formation, central Temblor Range, Kern County, Calif., and mega-invertebrate 

fossil localities in the Wygal Sandstone (X) and Cymric Shale ( ) Members (geology from Dibblee, 1968). The 

northwestern limit of the Wygal Sandstone Member is in sec. 17, T. 28 S., R. 19 E. (Glover, 1953).
MOLLUSC AN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

in thickness, separated by more friable, less calcareous, poorly exposed sandstone. The basal sandstone bed is coarse to very coarse grained and is 

characterized by abundant pelecypod valves and a 

few mollusk-bored cobbles. In the area between 

Carneros and Temblor Creeks, the basal sandstone 

usually overlies a poorly exposed, splintery, gray 

shale known locally as the Salt Creek Shale but 

recently renamed as the Cymric Shale Member 

(Dibblee, 1973) ; locally, however, the sandstone 

overlaps the Cymric Shale Member and directly 

overlies the Eocene Point of Rocks Sandstone 

(Stinemeyer and others, 1959, p. 6). From Santos 

Creek (fig. 3) northward the basal sandstone of the 

Wygal unconformably overlies the Point of Rocks 

Sandstone; it progressively truncates about 700 feet 

of strata in the Point of Rocks Sandstone between 

Santos Creek and its northwestern limit at Devilwater Creek (Glover, 1953). This contact is well 

exposed where it crosses sharp ridges on the north 

and south sides of Media Agua Creek (fig. 3).

Although an unconformity is not recognized at 

the base of the Wygal [Phacoides] Sandstone Member in basinward oil fields southeast of the Temblor 

Creek-Chico Martinez Creek area (Weddle, 1966; 

Foss and Blaisdell, 1968; Anderson and Land, 1969), 

there is a distinct unconformity at the base of the 

Wygal in most of the oil fields adjacent to the 

northeastern flank of the central and northern parts 

of the Temblor Range (Ritzius, 1954; Bruce, 1956; 

Park and Weddle, 1959; and Land, 1968). In the 

subsurface, the Wygal [Phacoides] Sandstone Member progressively overlaps and truncates Oligocene 

and upper Eocene formations in a westerly direction.

Surface and subsurface evidence indicates, therefore, that the unconformity at the base of the Wygal 

Sandstone Member is an even stronger and better 

defined regional feature than the one at the base 

of the Cymric [Salt Creek] Shale Member.

The basal sandstone of the Wygal Sandstone 

Member is well exposed about half a mile southeast 

of Zemorra Creek, in the southern part of the outcrop belt. There it contains abundant Crassostrea 

and scattered valves of the stratigraphically significant species Pecten sanctaecruzensis Arnold 

(USGS loc. M4467).

The stratigraphically higher fossiliferous strata 

are generally poorly exposed except in gullies and 

in areas of southern exposure on moderate to steep 

slopes. Pelecypod valves occur in fine-grained to 

very fine grained calcareous sandstone lenses or 

concretions. The valves are so abundant that the 

Wygal Sandstone Member can usually be recognized 

and mapped on the basis of fossil float generally

articulated valves of Lucinoma acutilineata and, to 

a lesser extent, Heteromacoma rostellata even in 

areas of low relief and on north-facing slopes.

The top of the Wygal Sandstone Member is 

marked by a 4- to 5-f oat-thick bed of white-weathering glauconitic sandstone. This bed is well exposed 

in trenches between Media Agua Creek and Stone 

Corral Creek (Ei/2Ei/2 sec. 23, T. 28 S., R. 19 E.), 

on the south side of Zemorra Creek (NW^SE^ 

sec. 9, T. 29 S., R. 20 E.), and about a mile northwest of Salt Creek (SW. cor. sec. 14, T. 29 S., R. 

20 E.). It is a characteristic subsurface marker bed 

in the Cymric oil field, the productive limits of 

which extend for a distance of 10 miles southeast 

of Temblor Creek (Anderson and Land, 1969).

Recent collections from 19 localities in the Wygal 

Sandstone Member, together with three older collections (USGS Iocs. 5149 and 9432; UCR 1235), 

have yielded a molluscan fauna of 50 taxa, principally pelecypods (table 1). The largest, best preserved assemblage is from the divide on the south 

side of Media Agua Creek (USGS Iocs. M3280 and 

M3772; 31 taxa). Here the base of the Wygal is 

marked by scattered calcareous sandstone concretions containing abundant pelecypod valves. In the 

upper part of this 6-foot-thick unit, Lucinoma acutilineata (Conrad) and Heteromacoma rostellata 

(Clark) are so abundant that this part can be 

called a Lucinoma-Heteromacoma bed. Gastropods 

are more common at this locality than elsewhere, 

but they constitute only a small fraction of the 

mollusk assemblage.

PROVINCIAL AGE AND CORRELATION

GENERAL CONSIDERATIONS

The lower part of the type Temblor Formation 

constitutes a unique stratigraphic continuum of 

marine middle Tertiary strata in the California 

Coast Ranges. Two molluscan stages of provincial 

late Oligocene and early Miocene age can be recognized from shallow-water faunal assemblages from 

sandstone members of the formation. These units 

are directly associated with benthonic foraminiferal 

assemblages from interbedded shale and siltstone 

that constitute the type section of the Zemorrian 

Stage of the provincial microfaunal sequence (Kleinpell, 1938). Elsewhere in the Coast Ranges of central and southern California, the Oligocene, and 

perhaps the early part of the Miocene, are usually 

represented by nonmarine strata the Sespe Formation and correlative units that constitute a marked 

hiatus between the widespread marine deposition 

of the Eocene and of the Miocene. The significant 

features of the Temblor Range sequence can be sum-
PROVINCIAL AGE AND CORRELATION

TABLE 1. Systematic list of mollusks from the Wygal Sandstone Member of the Temblor Formation, Temblor Range, Calif.

Fossil

Gastropods :

Cerithiid? _ _ _ _ _ _ _

Calyptraea diegoana (Conrad) _ __

Neverita, (Glossaulax) thomsonae

Sinum cf. 5. scopulosum (Conrad) -

Calicantharus cf. C. branneri

Bruclarkia seattlensis Durham __ __ 

Pelecypods :

Yoldia (Kalayoldia) tenuissima 

Clark _ __ ___ ___ _ _

Anadara { Anadara,) submontereyana 

Clark __ __ _ ____

CrenomytUusf cf. C.I arnoldi 

(Clark) _ ___ __ 

Pecten (Pecten) sanctaecruzensis

Vertipecten alexclarki Addicott,

Crasaostrea eldridgei ynezana

Lucinoma acutilineata (Conrad) _- 

Miltha (Miltha) sanctaecrucis 

(Arnold) _ _ _ _ - -

Felanietta harfordi (Anderson) __

Spisula cf. S. albaria (Conrad) 

n. sp.? _ ___ -_ -

ramonensis Packard - -- - 

cf. S. rushi Wagner and 

Schilling -_-

Tettina (Olcesia) piercei (Arnold)- 

( Oudardiaf ) emacerata Conrad

(Tellinetta) tenuilineata Clark __

Tellinat cf. T. Vancouver ensis Clark

Heteromacoma rostellata (Clark) _ 

Amiantis mathewsoni (Gabb)

n. sp 

dementia (Egesta) pertenuis 

(Gabb) _ _ - - _ -

Dosinia (Dosima) whitneyi (Gabb) 

Pitar (KatherineUa) cf. P. (K.) 

California (Clark) ____________

sp _______________________ 

Securella cf. S. cryptolineata

1 Pln t ^

Panopea ramonensia (Clark) ____ 

Scaphopod: 

Dentalium laneensis Hickman 

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marized as (1) the succession of shallow-water 

Oligocene and early Miocene molluscan assemblages 

in demonstrable superpositional relationships and 

(2) the alternation of these molluscan assemblages 

with thoroughly studied foraminiferal-bearing 

strata. What is offered, then, is a unique framework 

for the stratigraphic succession of shallow-water 

molluscan faunas from the Oligocene into the Miocene and an opportunity to relate these directly to 

the deeper water benthonic foraminiferal sequences. 

The biostratigraphic units in the lower part of

the type Temblor Formation that are taken to represent time-stratigraphic units of stage magnitude 

are represented by faunal assemblages from (1) the 

Wygal Sandstone Member and (2) the Agua and 

Carneros Sandstone Members. A third stage may 

be represented by a meager faunal assemblage from 

the Cymric Shale Member near the base of the 

Temblor Formation. The relationship of these units, 

and stratigraphically higher members of the Temblor Formation, to the standard Pacific coast megainvertebrate chronology of Weaver and others
8 MOLLUSCAN BIO STRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

(1944) is shown in figure 4. The Miocene megainvertebrate stages are enclosed in quotation marks 

here and throughout the text to differentiate them 

from rock-stratigraphic units bearing the same 

name and to signify that they have not been formally 

defined. The Refugian Stage (Schenck and Kleinpell, 

1936), usually considered to be a microfaunal stage, 

was originally defined on both foraminiferal and 

molluscan evidence. It is not, therefore, enclosed in 

quotation marks as are the other molluscan stages.

Formation

Temblor Formation 

(type)

Member

Buttonbed 

Sandstone

Media Shale

Carneros Sandstone

Santos Shale

Agna Sandstone^x

Santos Shale

Wygal Sandstone

Cymric Shale

Molluscan stage

"Temblor"

"Vaqueros"

Unnamed

'Lincoln" or Refugian

Foraminiferal 

stage

Relizian

Saucesian

Zemorrian 

(type)

FIGURE 4. Molluscan and foraminiferal provincial stage 

classification of the type Temblor Formation. Formational 

nomenclature is after Dibblee (1972). Molluscan control 

is indicated by the vertical bars; foraminiferal stage 

boundaries are from Stinemeyer, Beck, Ortalda, Espenscheid, Bainton, and O'Keefe (1959).

This report is concerned primarily with the 

fauna of the Wygal Sandstone Member and its bearing on the marine Oligocene of the provincial 

chronology. Heretofore this poorly known fauna had 

been assigned to the lower Miocene "Vaqueros 

Stage" of Weaver and others (1944), although the 

lack of "Vaqueros" index species had been noted by 

at least a few workers (Woodring and others, 

1940). It can now be shown that the Wygal Sandstone Member, or so-called Phacoides sand, is older 

than the "Vaqueros Stage" and that it represents 

an Oligocene interval in the California provincial 

molluscan sequence that has never been adequately 

defined. Secondary objectives are (1) delineation 

of the boundaries of the overlying "Vaqueros Stage" 

in the Temblor Range and (2) discussion of molluscan evidence of the provisional reassignment of the 

lowermost part of the basal shale, the Cymric Shale 

Member, to the Refugian Stage.

CYMRIC SHALE MEMBER

The Cymric Shale Member of the type Temblor 

Formation (Dibblee, 1972) has been assigned to the

"Vaqueros Stage" of the Pacific coast megainvertebrate chronology (Weaver and others, 1944. 

as "Barren" shale member of the Temblor Formation). This assignment, together with the subsequent inference (Kleinpell and Weaver, 1963, fig. 

5) that this unit falls within the biozone of Turritella inezana s. 1., was based on the assumption that 

the base of the Zemorrian Stage of the provincial 

microfaunal sequence is coincident with the lower 

boundary of the "Vaqueros Stage" (see also Corey, 

1954). So far as is known, however, there are no 

authenticated occurrences of molluscan assemblages 

referable to the "Vaqueros Stage" found together 

with Foraminifera referable to the lower part of 

the Zemorrian Stage. The known range of the Vaqueros fauna of Loel and Corey (1932) [= "Vaqueros Sitage"] corresponds to the upper part of the 

Saucesian Stage (Addicott, 1967a, p. C9). Moreover, 

the subsequent analysis of the fauna of the Wygal 

Sandstone Member, which overlies the Cymric Shale 

Member, indicates that it represents a pre- 

"Vaqueros Sitage" time-stratigraphic unit in the 

California provincial molluscan sequence.

Further revision of the age of this member in 

terms of the provincial sequences is suggested by a 

small collection of mollusks from 10 to 30 feet below 

the base of the Wygal Sandstone Member in an 

unnamed creek between Zemorra Creek and Salt 

Creek (California Univ., Riverside, loc. 1106). This 

collection includes Bruclarkia columbiana (Anderson and Martin) (pi. 9, figs. 22, 23), a well-defined 

gastropod that is restricted to the upper part of 

the Refugian Stage in California (Schenck and 

Kleinpell, 1936) and to the middle and upper part 

of the Refugian Stage [= Acila shumardi Zone and 

"Lincoln Stage"] of western Washington (Durham, 

1944). B. columbiana was previously reported from 

this locality as OlequaJiia lorenzana (Wagner and 

Schilling) by Addicott (1970b), who based his 

identification on one by Alex Clark (unpub. rept, 

1931, on file in the Geol. Dept., California Univ., 

Riverside), but Clark indicated that his two specimens might possibly be confused with Bruclarkia 

columbiana (Anderson and Martin). His unfigured 

specimen is an internal mold that is generically 

indeterminate; it seems to have a strongly noded 

penultimate whorl and could conceivably represent 

Olequahia. His other specimen, however, clearly is 

B. columbiana (pi. 9, figs. 22, 23).

The implications of this suggested stratigraphic 

revision are far reaching. Beds containing Bruclarkia columbiana can be confidently traced into 

the lowermost part of KleinpelPs (1938) type Zemorrian section, which is situated slightly more
PROVINCIAL AGE AND CORRELATION OF CYMRIC SHALE MEMBER

than a mile to the northeast (see Elliott and others, 

1968, p. 111). The occurrence of this significant 

index species suggests that part of the type Temblor 

Formation must also be of Refugian age and that 

the two stages, as originally defined, are in part 

coeval. It should be noted that the lower boundary 

of the Zemorrian Stage was originally placed at 

the base of the Cymric Shale Member [lower Temblor shale member] by Kleinpell (1938).

So far as can be determined, this indicated revision does not necessarily contravene foraminiferal 

control used by Kleinpell (1938, p. 40-45, 54, 105- 

108) in defining his Zemorrian Stage. His stratigraphically lowest sample from Carneros Creek 

(loc. la, 10 ft above the base of the member) contains only the long-ranging Eocene to Miocene 

species Plectofrondicularia vaughani. The only 

other assemblage from the Cymric Shale Member 

listed by Kleinpell (1938, loc. CM70) may have been 

obtained from beds stratigraphically higher than 

those in which Bruclarkia occurs. Kleinpell's sample 

was collected from a position about 50 feet above 

the base of the member in nearby Chico Martinez 

Creek (the thickness of the Cymric Shale Member 

in this area is variously reported as about 35 ft 

(Stinemeyer and others, 1959) and 75 ft (Kleinpell, 

1938)). This critical assemblage that Kleinpell 

(1938, p. 107, CM70) cited as indicative of the same 

"zone" as the diverse and stratigraphically diagnostic lower Zemorrian assemblages of the overlying lower part of the Santos Shale Member, for 

example, contains only seven taxa. Of these, only 

Buliminella curia seems to be restricted to postRefugian strata (R. L, Pierce, oral commun., May 

1971). Epistomina ramonensis, the zonal index of 

Kleinpell and Weaver's (1963, p. 41) lower subzone 

of the lower part of the Zemorrian Stage, which 

presumably is represented by the Cymric Shale 

Member, has never been recorded from the type 

Zemorrian. Furthermore, representatives of the 

stratigraphically diagnostic late Paleogene and early 

Neogene Uvigerina jacksonensis [C7. cocoaensis]- 

Siphogenerina transversa lineage of Lamb (1964) 

have never been recorded from the Cymric Shale 

Member or from this lowest subzone (Kleinpell and 

Weaver, 1963; Lamb, 1964). The Cymric, in fact, 

represents a critical gap between the highest stratigraphic occurrence of U. tumeyensis Lamb or U. 

vicksburgensis Cushman and Ellisor of Kleinpell 

and Weaver (1963) and the lowest stratigraphic 

occurrence of the presumed antecedent species S. 

nodifera Cushman and Kleinpell. The highest stratigraphic occurrence of U. tumeyensis is in strata 

assigned to the Refugian Stage by Kleinpell and

Weaver (1963), whose assignment is based in part 

on molluscan evidence; the lowest stratigraphic 

occurrence of S. nodifera is in the basal part of the 

Santos Shale Member in the lower part of the type 

Zemorrian section. Accordingly, the Cymric Shale 

Member, in terms of the Uvigerina-Siphogenerina 

sequence of Lamb (1964), represents a hiatus between the Refugian and the Zemorrian Stages.

The possibility that the lower boundary of the 

type section of the Zemorrian Stage should be 

revised and placed at a higher stratigraphic position at or near the top of the Cymric Shale 

Member is further suggested by analysis of fishscale assemblages from the lower part of the Temblor Formation by R. L. Pierce. Fish scales from 

the Cymric Shale Member near the base of the lower 

part of the Zemorrian Stage are considered by 

Pierce to be "very characteristic of the Refugian 

Stage of California," whereas those from the lower 

part of the Santos Shale Member near the top of 

lower part of the Zemorrian Stage are much different and are considered typically Zemorrian (R. L. 

Pierce, written commun., Sept. 3, 1971).

In summary, the scant molluscan evidence suggests that the basal shale of the Temblor Formation 

may be, at least in part, referable to the earlier 

defined Refugian Stage of Schenck and Kleinpell 

(1936), a stage defined on both molluscan and foraminiferal data. This correlation is supported by 

studies of fish scales from the lower part of the 

Temblor Formation of this area and is not necessarily contravened by published data on foraminifers from exposures of the Temblor Formation of 

this area. The suggested upward adjustment of the 

lower boundary of the type Zemorrian Stage would 

be in keeping with the principle of priority inasmuch as the Refugian Stage (Schenck and Kleinpell, 1936) was proposed before the Zemorrian 

Stage was defined (Kleinpell, 1938), although the 

name Zemorrian Stage had been introduced a few 

years earlier (Kleinpell, 1934).

Part of the Cymric Shale Member may thus be 

correlative with Wagner and Schilling's (1923) 

faunal assemblages from the upper part of their 

San Emigdio Formation and the lower part of their 

Pleito Formation along the southern margin of the 

San Joaquin basin. These units contain both mollusks and benthonic foraminifers referable to the 

Refugian Stage (DeLise, 1967; Kleinpell and 

Weaver, 1963). A somewhat larger assemblage of 

Refugian mollusks has been reported from sandstone in a landslide block about 10 to 15 miles to 

the southeast of Zemorra Creek near Crocker Flat 

(Simonson and Kreuger, 1942). Refugian index
10 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

species in this assemblage include Olequahia lorenzana (Wagner and Schilling), Turritella lorenzana 

(Wagner and Schilling), and Epitonium condoni 

Dall. Further study of this displaced stratal sequence is needed because the Refugian mollusks 

were said to be associated with foraminifers of 

Zemorrian age. Exposures of the Refugian Wagonwheel Formation of Smith (1956) in the southern 

part of the Diablo Range, about 30 miles to the 

northwest, contain an assemblage of deep-water 

pelecypods, principally Lucina aff. L. diegoensis 

Dickerson and Thyasira aff. T. disjuncta, that does 

not permit faunal correlation with shallow-water 

Refugian assemblages in the southern part of the 

San Joaquin basin.

WYGAL SANDSTONE MEMBER

Indirect evidence that the fauna of the Wygal 

Sandstone Member is of late Oligocene, pre- 

" Vaqueros" (early Miocene) age is that species restricted to the "Vaqueros Stage" occur only in 

stratigraphically higher sandstones in the type Temblor Formation. The shallow, inner sublittoral 

bathymetric environment indicated by the molluscan 

assemblages of the Wygal Sandstone Member is 

similar to that of the Vaqueros Formation, as previously noted by Woodring, Stewart, and Richards 

(1940). And, as might be expected, the generic 

composition of the Wygal molluscan fauna is not 

markedly different from that of the Vaqueros Formation of Loel and Corey (1932) 1 . Accordingly, one 

would expect to find some of the ubiquitous shallowwater index species of the "Vaqueros Stage" in the 

Wygal fauna, if it were deposited during the "Vaqueros age," particularly in view of the moderately 

large, diverse fauna of 50 shallow-water molluscan 

taxa recorded in table 2.

Inferred phylogenetic relationships of two stratigraphically important Oligocene to middle Miocene 

molluscan genera, Bruclarkia and Vertipecten, 

further strengthen the contention that the faunal 

assemblages of the Wygal Sandstone Member are 

older than the "Vaqueros." Bruclarkia is represented by B. seattlensis Durham, a species that 

seems to be a lineal antecedent of B. barkeriana 

forma santacruzana (Arnold), an early and middle 

Miocene species restricted to the "Vaqueros" and 

"Temblor Stages" (table 3). B. seattlensis occurs

1 Loel and Corey's (1932) Vaqueros Formation is not strictly a lithostratigraphic unit; rather, it was defined and recognized on a faunal 

basis and, therefore, closely fulfills the criteria for a time-stratigraphic 

unit (Kleinpell and Weaver, 1963; Addicott, 1970a). Accordingly, it is 

here referred to as "Vaqueros Stage." Quotation marks are used for this, 

and other stages, to indicate that they have not been formally defined 

and to distinguish them from rock-stratigraphic units bearing the same 

name.

stratigraphically above the upper Refugian index 

species B. columbiana (Anderson and Martin), from 

which it may have evolved both here and in western 

Washington (Durham, 1944, p. 116). Likewise, the 

pectinid Vertipecten alexclarki n. sp. from the Wygal 

Sandstone Member seems to be the lineal antecedent 

of V. perrini (Arnold), a species that first occurs 

in the "Vaqueros Stage" and that has its lowest 

stratigraphic occurrence in the Agua Sandstone 

Member, higher in the Temblor Formation (table 

3). The reported occurrence of V. perrini in the 

upper part of the Refugian Stage (Schenck and 

Kleinpell, 1936, p. 222) has never been documented 

in the literature. That occurrence may refer to a 

large pectinid from Effinger's (1935) Refugian 

Gaviota Formation of the Santa Ynez Mountains 

subsequently figured by Wilson (1954, pi. 18, figs. 

1, 2) as Pecten (Chlamys) cf. P. (C.) sespeensis 

Arnold (R. M. Kleinpell, oral commun., June 1971). 

Vertipecten is represented in the region of the type 

section of the Refugian Stage by V. yneziana 

(Arnold) (Kleinpell and Weaver, 1963).

The occurrence of Pecten sanctaecruzensis Arnold 

at the base of the Wygal Sandstone Member (USGS 

loc. M4467) is further evidence of a pre-"Vaqueros" 

position in the provincial mega-invertebrate chronology. As indicated by Loel and Corey (1932), this 

species does not occur in faunal assemblages referable to their Vaqueros Formation ["Vaqueros 

Stage"] ; they regard its occurrences in the Salinas 

Valley area and in the Santa Cruz Mountains as of 

pre-Vaqueros, Oligocene age. Although this classification was disputed by Schenck (1935, p. 521-522) 

based on his mapping of the type locality of P. 

sanctaecruzensis in the Vaqueros Sandstone of the 

Santa Cruz Mountains and by subsequent workers 

(Brabb, 1964; Burchfiel, 1964), the fact remains 

that this species has never been found associated 

with mollusks restricted to Loel and Corey's (1932) 

Vaqueros Formation [their "formation" being, as 

previously indicated, a time-stratigraphic unit that 

has subsequently become known as the "Vaqueros 

Stage"]. This fact was recognized initially by Arnold 

(1908), who emphasized that P. sanctaecruzensis 

and the associated molluscan assemblage in the 

Santa Cruz Mountains were more closely related to 

the fauna of the underlying San Lorenzo Formation 

than to his overlying Vaqueros Sandstone [again 

Arnold's (1908) Vaqueros Sandstone was essentially 

a time-stratigraphic unit defined on biostratigraphic 

criteria, and its lower boundary was defined on essentially the same criteria as Loel and Corey's 

Vaqueros Formation]. Moreover, the stratigraphic 

association of P. sanctaecruzensis with foraminifers
PROVINCIAL AGE AND CORRELATION OF WYGAL SANDSTONE MEMBER 11

TABLE 2. Ranges of specifically determined mollusks from the Wygal Sandstone Member of the 

Temblor Formation in terms of the Pacific coast provincial mega-invertebrate chronology

["Stages" are modified from Weaver and others (1944), Durham (1964), and Corey (1964)]

Series

Stage : 

Oregon and Washington ......

California

Gastropods:

Sinum cf. S. scopulosum (Conrad)

Calicantharus cf. C. branneri (Clark and Arnold)

Bruclarkia seattlensis Durham ....

Pelecypods:

Yoldia tenuissiina Clark

Crenomytilusl cf. C.? arnoldi (Clark)

Pecien sanctaecruzensis Arnold

Crassostrea eldridgei ynezana (Loel and Corey) _____ 

Here excavata (Carpenter) ...... .................

Lucinoma acutilineata (Conrad)

Miltha sanctaecrucis (Arnold)

Felaniella harfordi (Anderson)

Spisula cf. S. albaria (Conrad)

Spisula n. sp. ?

Spisula ramonensis Packard

Spisula cf. S. rushi Wagner and Schilling

dementia pertenuis (Gabb) ___......._____._.........

Dosinia whitneyi (Gabb)

Panopea ramonensis (Clark) ...--.

Scaphopod: 

Dentalium laneensis Hickman _ _ .....................

Eocene

"Tejon"

"Tejon"

"Keasey"

Oligocene

"Lincoln"

Refugian

Miocene

^? 

"Blakeley" ^7

Unnamed

"Vaqueros"

"Temblor"

"Margaritan"

?

of early Zemorrian age in both the Temblor Range 

and the Santa Cruz Mountains (Burchfiel, 1964) is 

suggestive of a pre-"Vaqueros" position in the 

provincial mega-invertebrate sequence because 

"Vaqueros" index species are not known to be associated with foraminiferal assemblages below the 

upper part of the Zemorrian Stage (p. 8).

Unfortunately, no representatives of the stratigraphically important gastropod genus Turritella 

have been found in the Wygal Sandstone Member. 

Nor has it been found in the upper part of the 

Pleito Formation of Wagner and Schilling (1923) 

of the nearby San Emigdio Mountains, a unit that 

is regarded by myself and by at least some workers

(Kleinpell and Weaver, 1963) as coeval with the 

lower sandstone member of the type Temblor Formation. The absence of Turritella from these formations complicates correlation: Turritella lineages 

(Merriam, 1941) as well as the pectinids are the 

most important means of correlation and age determination by mega-invertebrates in the Pacific coast 

Tertiary.

The post-Refugian age of the molluscan fauna of 

the Wygal Sandstone Member is indicated by (1) 

the absence of shallow-water species that are restricted to Refugian strata in other parts of the 

San Joaquin basin, (2) a significant number of 

genera and species that are not known to occur in
12 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

TABLE 3. Ranges of some species of Bruclarkia and Vertipecten referred to in text

Species

Bruclarkia

barkeriana forma 

santacruzana

seattlensis 

columbiana

Vertipecten 

perrini 

alexclarki 

yneziana

Provincial stage

"Temblor" "Vaqueros" Unnamed Refugian

assemblages as old as Refugian in California (tables 

4 and 5), and (3) the abrupt appearance of molluscan genera (post-Refugian genera and species) 

indicative of a much warmer water environment 

than occurred during the Refugian (Addicott, 1969, 

1970b).

Although there are some species in common with 

the Refugian Stage ("Lincoln Stage" of Oregon and 

Washington), as might be expected, most of the 

Refugian species characteristic of the upper part of

TABLE 4. Molluscan species from the 

Wygal Sandstone Member that are not 

known to occur in strata of Refugian age

[Species restricted to formations of late Oligocene 

age in California are indicated by an asterisk (*). 

The other species range upward in strata of 

"Vaqueros" and (or) younger age]

Gastropods:

Calicantharus dalli (Clark)

cf. C. branneri (Clark and Arnold) 

Pelecypods:

Anadara submontereyana (Clark)

Crassostrea eldridgei yneziana (Loel 

and Corey)

Crenomytilus expansus (Arnold)

Dosinia whitneyi (Gabb)

Felaniella harfordi (Anderson)

Macoma arctata (Conrad)

Miltha sanctaecrucis (Arnold)

*Pecten sanctaecruzensis (Arnold) 

Spisula n. sp.?

cf. S. albaria (Conrad) 

cf. S. rushi Wagner and Schilling 

Tellina piercei (Arnold) 

emacerata (Conrad)

*Vertipecten alexclarki Addicott n. sp.

the San Emigdio and lower part of the Pleito Formations of Wagner and Schilling (1923) from the 

southern margin of the San Joaquin basin do not 

occur in the Wygal Sandstone Member, nor do they 

range upward into the upper part of the Pleito 

Formation that is, in part, correlative with the 

Wygal Sandstone Member. Some of the Refugian 

species recorded by Wagner and Schilling (1923) 

and DeLise (1967) that do not occur in the Wygal 

Sandstone Member are: Acrilla dickersoni Durham, 

Bruclarkia columbiana (Anderson and Martin), 

Bullia clarki Wagner and Schilling, Epitonium 

condoni Ball s. 1., Molopophorus dalli (Anderson 

and Martin), Olequahia lorenzana (Wagner and 

Schilling), Perse lincolnensis (Van Winkle), Siphonalia merriami Wagner and Schilling, Acila 

shumardi (Dall), and Macrocallista pittsburgensis 

Ball.

There is ample evidence, therefore, that the 

fauna of the Wygal Sandstone Member of the Temblor Formation occupies a position between the 

Refugian Stage and the "Vaqueros Stage" of the 

provincial mega-invertebrate chronology. It is likewise clear that the molluscan fauna of the Refugian 

Stage is not directly succeeded by faunal assemblages of the "Turritella inezana zone" (= the 

"Vaqueros Stage" of later usage (Weaver and 

others, 1944)) as believed by Schenck and Kleinpell 

(1936) and Kleinpell and Weaver (1963).

There is no formally or informally proposed timestratigraphic unit in the California provincial molluscan sequence to which the Wygal fauna can be 

assigned. It is of post-Refugian age and is, in part, 

coeval with the "Blakeley Stage" of western Washington, presumably the lower part, the Echinophoria 

rex Zone of Burham (1944). Correlation with the 

western Washington molluscan sequence, however, 

is based largely on strati graphic position and foraminiferal evidence and only indirectly on molluscan 

data. 2

The post-Refugian age of the type sections of the 

"Blakeley Stage" is well established both on molluscan (Burham, 1944) and foraminiferal evidence 

(Rau, 1964; Fullmer, 1965). There is, however, 

evidence that at least part of the "Blakeley" is coeval 

with the "Vaqueros Stage" (Kleinpell, 1938, p. 153;

2 The difficulty in post-Refugian molluscan correlation between the southern 

part of California and western Washington is the result of the intensification of latitudinal taxonomic gradients, which began during the late 

Oligocene (Addicott, 1970c). This intensification is reflected in the decidedly warm-water aspect of the Wygal assemb'ages as contrasted with 

the temperate aspect of those of the type area of the "Blakeley Stage." 

Moreover, the bathymetric environment indicated by the "Blakeley" fauna, 

particularly the lower part the Echinophoria rex Zone of Durham (1944) 

 is relatively deeper than that represented by the Wygal assemblages and 

further complicates correlation.

493-696 0-73-2
PROVINCIAL AGE AND CORRELATION OF SANTOS SHALE MEMBER 13

TABLE 5. Molluscan genera and subgenera 

from the Wygal Sandstone Member that 

are not known to occur in strata of Refugian age

Gastropod:

Tegula 

Pelecypods:

Egesta Oudardia

Leptopectenl Pecten s. s.

Miltha Securella

Olcesia

Vanderhoof, 1942; Kleinpell and Weaver, 1963; 

Addicott, 1967b). Although this equivalence can be 

rather convincingly demonstrated by foraminiferal 

correlation, the latitudinal taxonomic gradient in 

molluscan faunas (footnote, p. 12) reduces the 

number of species common to both sequences to 

such a point that this supposed equivalence may 

never be proven or disproven. Many, if not most, of 

the generic lineages used in the time-stratigraphic 

subdivision of the Oligocene and early Miocene of 

western Washington (Durham, 1944, p. 115-116) 

are either incompletely represented or are not present at all in the warmer water assemblages of the 

San Joaquin basin. Among these critical lineages 

are Aforia, Ancistrolepis, Liracassis [Echinophoria 

of authors], Molopophorus, Bathybembix \Turcicula 

of authors], and Turritella. The one direct line of 

evidence supporting correlation with the "Blakeley 

Stage" of western Washington is the occurrence of 

the gastropod Bruclarkia seattlensis Durham in the 

Wygal assemblages. This species is restricted to the 

lower part of the "Blakeley Stage" (the Echinophoria rex Zone) of western Washington. It seems 

probable that the fauna of the Wygal Sandstone 

Member falls within the biozone of Acila gettysburgensis, but this species which ranges from the late 

Oligocene to middle Miocene and which is so characteristic of late Oligocene and early Miocene strata in 

Oregon and Washington, has been recorded from 

only two areas in California: a doubtful locality in 

the Santa Cruz Mountains (Schenck, 1936) and the 

San Ramon Sandstone near Mount Diablo (Clark, 

1918). The San Ramon Sandstone, however, seems 

to be somewhat younger than the Wygal Sandstone 

Member and coeval units in western Washington 

assigned to the Echinophoria rex Zone, according to 

a reanalysis of its invertebrate fauna by Primmer 

(1965, p. 52-53), who assigned it to the upper part 

of the "Blakeley Stage" (the Echinophoria apta 

zone).

In view of the difficulty in correlating late Oligocene molluscan faunas of California with those of 

western Washington, it seems appropriate to establish a separate time-stratigraphic unit in California. 

The evidence presented in this report is judged adequate for recognition of a unit of stage magnitude, 

even though it is based on a fauna that has an 

extremely limited stratigraphic range. But because 

thoroughgoing biostratigraphic study of the coeval 

shallow-water molluscan fauna from the upper part 

of the Pleito Formation (Wagner and Schilling, 

1923) of the southern margin of the San Joaquin 

basin has not been carried out, this time-stratigraphic unit must, for the time being, remain unnamed. In fact, the dominantly shallow-water sequence of Refugian through "Vaqueros" molluscan 

faunas of the San Emigdio Mountains should provide the best standard section for a late Oligocene 

provincial stage in California. Other molluscan 

faunas of this age from the California Coast Ranges 

are known to occur in the tuff member of the Kirker 

Formation of Primmer (1965), in the lower part of 

the Vaqueros Formation of Burchfiel (1964) and 

of Brabb (1964), and in the Santa Lucia Range 

(Edwards, 1940). Reported occurrences in the 

Alegria Formation of Dibblee (1950) of the western 

Santa Ynez Mountains (Kleinpell and Weaver, 

1963) were later reassigned to the Refugian Stage 

(Weaver and Franz, 1967).

Molluscan data do not seem to support the claim 

that the Wygal Sandstone Member [lower Temblor 

sandstone of Curran (1943)] is coeval with the 

Quail Canyon Sandstone Member of the Vaqueros 

Formation (Dibblee, 1973) [formerly the Soda Lake 

Sandstone Member] of the Cuyama Valley area west 

of the San Andreas fault (Kleinpell and Weaver, 

1963), and by inference, of pre-"Vaqueros" age. 

Molluscan assemblages from exposures of this unit 

in the eastern Caliente Range collected by J. G. 

Vedder include Crassostrea sp. and the "Vaqueros" 

index species Chlamys hertleini (Loel and Corey) 

(USGS loc. M3511). Accordingly, the Quail Canyon 

Sandstone Member of the Vaqueros Formation is 

younger than the Wygal Sandstone Member and 

should be correlated with the Agua Sandstone Member or with stratigraphically higher portions of the 

type Temblor Formation.

SANTOS SHALE MEMBER

The lower part of the Santos Shale Member, below 

the Agua Sandstone Member, includes the boundary 

between the lower part and the upper part of Kleinpell's (1938) Zemorrian Stage. Only one molluscan 

assemblage has been collected from the Santos Shale 

Member (USGS loc. M3983) less than 200 feet 

stratigraphically above the Wygal Sandstone Member on Temblor Creek. This small assemblage con493-696 O - 73 - 3
14 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

tains some specifically indeterminate gastropods and 

pelecypods (Calyptraea, Cancellaria, Bruclarkial, 

Leptopectenl, and Spisula sp.) as well as the long 

ranging pelecypods Lucinoma acutilineata and 

Macoma arctata. None of these genera or species 

permits unqualified assignment to either the unnamed stage represented by the fauna of the Wygal 

Sandstone Member or the "Vaqueros Stage" represented by mollusks from the stratigraphically higher 

Agua and Carneros Sandstone Members. The boundary between these two molluscan units is arbitrarily 

placed in the lower part of the Santos Shale Member so as to correspond to the boundary between the 

lower and upper parts of the Zemorrian Stage 

(Kleinpell, 1938, p. 111). The reason for this placement is that, elsewhere in California, mollusk assemblages of the "Vaqueros Stage" have their lowest 

stratigraphic occurrence in strata referable to the 

upper part of the Zemorrian Stage (Addicott, 

1967a).

AGUA SANDSTONE MEMBER

The lowest stratigraphic occurrence of mollusks 

characteristic of Loel and Corey's (1932) Vaqueros 

Formation [= "Vaqueros Stage" of later usage 

(p. 10)] in the Temblor Formation of the central 

and northern parts of the Temblor Range is in the 

Agua Sandstone Member. The initial recognition of 

the "Vaqueros" index species Crassostrea vaquerosensis (Loel and Corey) and Macrochlamis magnolia 

(Conrad) from unspecified localities between Carneros Creek and Bitterwater Canyon (Clark and 

Clark, 1935) has been verified by subsequent collections: Macrochlamis magnolia occurs near the 

mouth of Cedar Canyon (USGS loc. M2631; Stanford Univ. loc. 2682, Heikkila and MacLeod, 1951), 

and Crassostrea vaquerosensis occurs between Stone 

Corral Canyon and Media Agua Creek (USGS loc. 

M4464) several miles to the southeast. The "Vaqueros" and "Temblor" species Vertipecten perrini 

(Arnold) also has been collected from USGS locality 

M2631. These and other molluscan taxa collected 

from the Agua Sandstone Member are listed in table 

6. These species are also represented in faunal 

assemblages from the so-called Vaqueros Formation 

of the San Emigdio Mountains of the southern margin of the San Joaquin basin (Loel and Corey, 1932) 

and from the Jewett Sand of the southeastern margin of the basin (Loel and Corey, 1932; Addicott, 

1970a).

The Agua Sandstone Member of the type Temblor 

Formation is assigned to the upper part of the Zemorrian Stage of the provincial microfaunal seTABLE 6. Mollusks from the Agua Sandstone Member of 

the Temblor Formation

Crassostrea aff. C. titan (Conrad)

vaquerosensis (Loel and Corey) _ _

ICrassostrea (fragments) _ _ _ _

Heteromacoma rostellata (Clark) _ _

IKatherinella _ _ _ _ _ __

Lucinoma acutilineata (Conrad)

Vertivecten verrini (Arnold) _

USG

M2631

V

V

V

S loc. I

M3982

V

V

v

?

Jo.

M4464

X

quence (Kleinpell, 1938; Stinemeyer and others, 

1959; Kleinpell and Weaver, 1963).

PALEOBATHYMETRY

Larger invertebrates from the Wygal Sandstone 

Member are indicative of a relatively shallow-water 

depositional environment, according to present-day 

bathymetric ranges of those genera that are still 

living in the eastern North Pacific. Almost without 

exception modern depth ranges of these genera 

define an overlap in the upper part of the inner 

sublittoral zone between about 10 and 20 fathoms.

A few genera are restricted to, or are more characteristic of, environments shallower than 10 

fathoms: Crassostrea, Crenomytilus (an extinct 

genus similar to Mytilus), and Tegula. However, of 

these, Crenomytilus and Tegula are of uncommon 

occurrence in the Wygal Sandstone Member, and 

Crassostrea is usually represented by disarticulated, 

broken valves possibly indicative of displacement 

from an initially very shallow water site of deposition into somewhat deeper water.

Genera of deeper water aspect Acila, Lucinoma, 

and Miltha are generally found living at somewhat 

greater depths than 10 to 20 fathoms in warm-water 

latitudes along the Pacific coast. Species of Acila 

are recorded from as shallow as 10 to 15 fathoms 

(Smith and Gordon, 1948; Schenck, 1936), but 

these records are generally from temperate latitudes. 

Lucinoma, by far the most abundant mollusk in the 

Wygal assemblages, occurs in middle sublittoral 

depths, 28 to 45 fathoms, in tropical latitudes of the 

eastern Pacific (Keen, 1971), but in the upper 

reaches of the sublittoral in temperate latitudes, 8 

to 10 fathoms, (Smith and Gordon, 1948). The indicated present-day equatorward bathymetric gradient 

based on these records of Lucinoma annulata, a 

modern analog of the fossil species L. acutilineata, 

seems to be an example of equatorial submergence. 

Although there are a few genera of tropical aspect 

in the Wygal Sandstone Member (p. 16), the composition of the fauna is more suggestive of warmtemperate to subtropical conditions. Therefore, a
ZOOGEOGRAPHY AND PALEOCLIMATOLOGY 15

generalized interpolation between the 8- to 10- 

fathom records of modern Lucinoma in temperate 

latitudes and the 30- to 50-fathom records of it in 

tropical latitudes would suggest an upper limit of 

bathymetric occurrence within the postulated 10- to 

20-fathom depth range of the Wygal faunal assemblages. Keen (1971) recorded Miltha as occurring 

in water depths of about 30 fathoms or greater in 

the northern part of the Tropical or Panamic molluscan province of Mexico. Significantly shallower 

modern occurrences are suggested, however, by an 

intertidal record of this genus near the tip of Baja 

California, Mexico (Pilstory and Lowe, 1933).

The Wygal faunal assemblages bear some similarity to late Pleistocene molluscan communities of 

the Californian Province (Valentine, 1961; Valentine and Mallory, 1965). Comparisons are difficult, 

however, because a number of the Pleistocene genera 

do not occur in pre-Neogene assemblages of the 

Pacific coast area and because these Pleistocene 

assemblages seem to be of cooler water aspect than 

those of the Wygal Sandstone Member. Nevertheless, many of the late Oligocene species are represented by analogs in the Dosinia ponderosa element 

of Valentine's (1961) shallow inner sublittoral community, a sandy substrate association representative 

of depths between 5 and 15 fathoms.

Bathymetric inferences based on benthonic foraminiferal assemblages from shales underlying and 

overlying the Wygal Sandstone Member are suggestive of significantly greater depths. Foraminifers 

from the underlying Cymric Shale Member listed by 

Kleinpell (1938, Iocs, la and CM70), for example, 

are indicative of the middle to lower part of the 

bathyal zone (about 3,000 to 6,000 feet), according 

to the classification of San Joaquin basin foraminiferal biofacies by Bandy and Arnal (1969, p. 787- 

791). These inferences are based on the deep-water 

species Cyclamina incisa, Gyroidina soldanii, and 

Plectofrondicularia vaughani. Additional foraminiferal assemblages from the Cymric Shale Member 

studied by R. L. Pierce (written commun., April 

1969) are also indicative of middle bathyal or 

deeper depositional environment, according to the 

classification of Bandy and Arnal. An assemblage 

from the basal part of the Santos Shale Member directly overlying the Wygal Sandstone Member in 

Chico Martinez Creek also studied by Pierce (written commun., April 1969) includes species listed by 

Bandy and Arnal (1969) as characteristic of their 

lower bathyal and abyssal biofacies. Included are 

Siphogenerina nodifera, Cibicides floridanus, Gyroidina soldanii, and Plectofrondicularia cf. P. californica.

When these depths are contrasted with the indicated inner sublittoral depositional environment of 

the intervening Wygal Sandstone Member, late 

Oligocene vertical oscillation of the basin floor 

amounting from 3,000 to as much as 6,000 feet is 

indicated. Comparable downwarping of the floor of 

the San Joaquin basin in areas west of Bakersfield 

and southeast of Taft during the Zemorrian Stage 

has been inferred by Bandy and Arnal (1969, fig. 5) 

based on analysis of isopach data and inferred 

foraminiferal biofacies. However, their inferences 

of little or no differential vertical movement of the 

basin floor and continuous deep-water facies in the 

vicinity of the type section of the Zemorrian Stage 

at this time (Bandy and Arnal, 1969, fig. 5) are 

contrary to the evidence indicated by the larger 

invertebrate fauna of the Wygal Sandstone Member. Rather, it seems that an extensive oscillatory 

vertical movement of the basin floor must have 

occurred during the Oligocene in the vicinity of what 

is now the northeastern margin of the Temblor 

Range. The strong erosional unconformity at the 

base of the Wygal Sandstone Member and the shallow inner sublittoral depths indicated by molluscan 

assemblages of this member contrast sharply with 

the middle to lower bathyal foraminiferal biofacies 

of the underlying Cymric Shale Member and the 

overlying Santos Shale Member.

The possibility that the Wygal assemblages were 

displaced downslope and redeposited in bathyal 

depths indicated by the foraminiferal assemblages 

seems remote. The extremely abundant and relatively well-preserved mollusk shells, for example, 

generally are not fragmented and disarticulated, as 

are the scattered shallow-water pectinids and broken 

valves of Tivelal found in the stratigraphically 

higher Carneros Sandstone Member, which also 

occurs between deep-water foraminiferal assemblages of the Santos and Media Shale Members.

ZOOGEOGRAPHY AND PALEOCLIMATOLOGY

The molluscan fauna of the Wygal Sandstone 

Member of the Temblor Formation marks the beginning of a late Oligocene to late Miocene period 

during which molluscan faunas of the San Joaquin 

basin were characterized by a sizeable element of 

warm-water genera. These shallow-water genera 

are termed extralimital in the sense that their 

modern limits of geographic distribution along the 

Pacific coast do not reach as far north as the latitude of the fossiliferous exposures (lat 35.5° N.). 

Extralimital, warm-water taxa make up 41 percent 

of the still-living molluscan genera represented in 

the Wygal faunal assemblages. They are almost
16 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

equally divided, in terms of the northernmost 

present-day geographic limits of range between the 

Panamic, Surian, and Californian molluscan provinces of Valentine (1966). The shallow-water marine climates of these provinces are characterized, 

respectively, as inner tropical, outer tropical, and 

warm temperate (Hall, 1964).

During the late Oligocene, the central California 

area seems to have been a northern outpost for 

almost all these genera. Only a scattering of warmwater genera reached as far north as western Washington during the late Oligocene where a very small 

percentage (11 percent) of the still-living genera 

of the presumably coeval Echinophoria rex Zone of 

Durham (1944) are considered to be of warm-water 

aspect (Addicott, 1970c).

Warm-water genera represented in the Wygal 

assemblages and their northernmost limits of distribution in modern shallow-water molluscan provinces of the eastern North Pacific are as follows: 

Panamic Ficus, Miltha, dementia; Surian 

Natica s. s., Anadara s. s., Crassostrea, Dosinia; 

Californian Neverita, Kelletia, Here, Tellinella, 

Amiantis. In this late Oligocene fauna a substantial 

number of the extinct genera, or of genera that are 

no longer living along the margin of the eastern 

North Pacific, may also be of warm-water aspect: 

Siphonalial, Crenomytilus, Vertipecten, and Olcesia. 

This judgment is based both on the modern distribution of closely related molluscan genera and on 

the geographic distribution of these extinct genera 

in warm-water Tertiary assemblages along the 

Pacific coast.

Further evidence of very warm, shallow-water 

conditions during deposition of the Wygal Sandstone Member is furnished by the occurrence of the 

hermatypic coral Favites in collections from USGS 

locality M3280 near Media Agua Creek. Modern 

occurrences of this inner sublittoral genus are restricted to the tropical latitudes of the Indo-Pacific 

region and the Red Sea. According to J. Wyatt 

Durham (oral commun., Jan. 1971), who identified 

these specimens, and Durham and Allison (1960, p. 

72), Favites has not previously been reported from 

the Cenozoic of the eastern Pacific margin.

The zoogeographic relationship of the warm-water 

molluscan genera in the Wygal fauna to the temperate-water middle Oligocene fauna of the San 

Joaquin basin and to subsequent warm-water Miocene faunas of this area is depicted in figure 5. The 

present study has refined the systematic classification of the Wygal fauna to the extent that a more 

accurate zoogeographic analysis than was presented 

in a recent report (Addicott, 1970a, fig. 4) can be

40 30 

TIME. IN

20 10 

MILLIONS OF YEARS

FIGURE 5. Zoogeographic profiles for selected Tertiary 

faunal assemblages from the San Joaquin basin, California (Addicott, 1970a). Cumulative percentages express 

the modern warm-water zoogeographic provinces in which 

northern end points of range of extant genera occur: 

Panamic, 6° S.-23 0 N.; Surian, 23° N.-280 N.; Californian, 

28° N.-34.50 N. The sequence of provincial molluscan 

stages is modified from Weaver and others (1944) and 

Corey (1954). Numbers refer to faunal assemblages as 

follows: (1) Domengine Formation, southern Diablo 

Range; (2) San Emigdio and Pleito Formations of Wagner and Schilling (1923), San Emigdio Mountains; (4) 

Wygal Sandstone Member of the Temblor Formation, 

Temblor Range; (5) Jewett Sand, Kern River area; (6) 

lower part of the Olcese Sand, Kern River area; (7) 

upper part of the Olcese Sand and lower part of the 

Round Mountain Silt, Kern River area; (8) Santa Margarita Formation, Tejon Hills; (9) Santa Margarita Formation, Coalinga area; (10-12) Etchegoin Formation, 

Coalinga area; (13) Etchegoin Formation, Kettleman 

Hills; (14) San Joaquin Formation, Kettleman Hills.

made. Accordingly, cumulative percentages of late 

Oligocene warm-water genera (Panamic and Surian) are somewhat higher than previously calculated and are almost the same as those for the 

fauna of the overlying "Vaqueros Stage." However, 

zoogeographic relationships of these two successive 

faunal units late Oligocene and early Miocene 

are still clouded by the fact that the late Oligocene 

fauna is relatively poorly known, having only about 

half as many taxa as the early Miocene fauna. The 

disparity in size seems to be in the lack of a diverse 

gastropod element in the Wygal assemblages.

SYSTEMATIC DESCRIPTIONS

Only those references accompanied by illustrations of specimens are included in the following 

synonymies. Reports that list some of the more
SYSTEMATIC DESCRIPTIONS 17

common molluscan taxa from the Wygal Sandstone 

Member of the Temblor Formation are reviewed in 

an annotated list of literature (p. 3). The plates 

include a few illustrations of Oligocene and Miocene 

mollusks from other stratal units for comparative 

purposes. Entries in the synonymies are as originally used by the authors; a few contain lapses.

Fifty molluscan taxa are treated systematically; 

all but one of these are figured. One new species and 

a new tellinid subgenus are described: Vertipecten 

alexclarki n. sp. and Olcesia n. subgen. Five additional taxa Tegula n. sp., Natica (Natica) n. sp., 

Polinices n. sp., Spisula n. sp. ?, and Amiantis n. 

sp. seem to be undescribed but are represented by 

material that is too incomplete or too poorly preserved to permit formal description. The systematic 

arrangement of gastropods is after Keen (1963) ; 

of pelecypods, after McCormick and Moore (1969). 

Other larger marine invertebrates from the Wygal 

Sandstone Member include the hermatypic coral 

Favites, and undetermined solitary, branching coral, 

and an encrusting bryozoan Antroporal sp.

Abbreviations used in tabulating the occurrences 

of molluscan taxa in the type Temblor Formation 

are:

USGS ___U.S. Geological Survey, Washington, D.C., 

locality register (locality numbers have 

no letter prefix).

USGS M .__U.S. Geological Survey, Menlo Park, Calif., 

Cenozoic locality register.

UCMP __ -California University Museum of Paleontology, Berkeley, Calif.

UCR ______California University, Riverside, Calif.

Other fossil depositories are:

UO ______ Oregon University, Eugene, Oreg.

SU _____Stanford University, Stanford, Calif.

GAS ____-California Academy of Science, San Francisco, Calif.

ANSP __-Academy of Natural Sciences, Philadelphia, 

Pa.

Class GASTROPODA 

Order ARCHAEOGASTROPODA

Family TROCH1DAE 

Genus TEGULA Lesson, 1835

Tegula n. sp. 

Plate 8, figures 2, 4

Two incompletely preserved specimens of a moderately small, smooth-shelled trochid represent the 

shallow-water genus Tegula; a fragment in USGS 

collection M4466 may also be this trochid. The two 

specimens have somewhat different whorl profiles. 

The better preserved specimen (pi. 8, fig. 4) has an 

almost flat whorl profile; the more poorly preserved 

specimen (pi. 8, fig. 2) has a more strongly convex 

whorl profile and a faint subsutural tabulation on 

the body whorl. Because the inner margin of the

aperture on one of the specimens shows a fairly 

strong tooth, the specimen can be assigned to 

Tegula.

This Tegula was first recorded from the Wygal 

Sandstone Member of the Temblor Formation by 

Alex Clark (unpub. data, 1931 and 1932, deposited 

at California University, Riverside), who first recognized that it was an undescribed species. Clark's 

localities (EC-89 [= UCR 1235] and EC-125A) 

and USGS locality M3578 are from exposures about 

3/4 to 11/4 miles southeast of Zemorra Creek (fig. 3). 

One of his specimens is figured on plate 8 (fig. 4).

Tegula n. sp. is similar to the smooth-shelled 

middle Miocene species T. laevis Addicott (1970a, 

p. 41-42, pi. 1, figs. 2, 3, 5-7) from the Kern River 

area of the eastern margin of the San Joaquin basin. 

The Miocene species differs, however, in having 

strongly convex whorls and a narrow, but welldefined, subsutural tabulation.

This is the oldest record of the genus Tegula. The 

oldest previously known record was in the Miocene 

(Knight and others, 1960, p. 254) ; it may have been 

based on the early Miocene species T. malibuensis 

Loel and Corey (1932) from the Vaqueros Formation of California.

Localities. USGS M3578, M4466?, UCR 1235.

Order MESOGASTROPODA 

Family CERITHIIDAE?

Cerithiid?

Plate 8, figure 5

This moderately small, very poorly preserved 

conispiral gastropod which has a flat whorl profile 

seems to be a cerithiid. The body whorl is broken, 

and there are no traces of sculpture on the whorls 

of the spire.

Locality. USGS M3578.

Family CALYPTRAEIDAE 

Genus CALYPTRAEA Lamarck, 1799

Calyptraea diegoana (Conrad)

Plate 8, figures 8, 10, 17, 18 

1855. Trochita diegoana Conrad, U.S. 33rd Gong., 1st sess.,

H. Ex. Doc. 129, p. 17. 

1857. Trochita diegoana Conrad. Conrad, U.S. 33rd Gong.,

2d sess., S. Ex. Doc. 78, p. 327, pi. 5, fig. 42. 

1864. Galerus excentricus Gabb, California Geol. Survey,

Paleontology, v. 1, sec. 4, p. 136, pi. 20, fig. 95, pi.

29, figs. 232, 232a. 

1907. Galerus excentricus Gabb. Arnold, U.S. Geol. Survey

Bull. 321, pi. 10, figs. 3a, 3b. 

1910. Galerus excentricus Gabb. Arnold, U.S. Geol. Survey

Bull. 396, p. 112, pi. 4, fig. 8 [Imprint 1909.] 

1910. Galerus excentricus Gabb. Arnold and Anderson, U.S.

Geol. Survey Bull. 398, pi. 26, fig. 8. 

1916. Calyptraea washingtonensis Weaver, Washington

Univ. [Seattle] Pubs. Geology, v. 1, p. 44, pi. 3,

fig. 44.
18 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

1927. Calyptraea diegoana (Conrad). Stewart, Acad. Nat.

Sci. Philadelphia Proc., v. 78, p. 340-341, pi. 27,

fig. 15. 

1933. Calyptraea washingtonensis Weaver, California Univ.

Pubs. Geol. Sci. Bull., v. 23, no. 3, p. 137, pi. 14,

fig. 25. 

1938. Calyptraea diegoana (Conrad). Turner, Geol. Soc.

America Spec. Paper 10, p. 89-90, pi. 20, figs. 1, 2. 

1942. Calyptraea diegoana (Conrad). Weaver, Washington

Univ. [Seattle] Pubs. Geology, v. 5, p. 351-352,

pi. 71, figs. 16, 20, pi. 103, fig. 3.

1942. Calyptraea washingtonensis Weaver. Weaver, Washington Univ. [Seattle] Pubs. Geology, v. 5, p. 352-

353, pi. 71, figs. 19, 22. 

1963. Calyptraea diegoana (Conrad). Weaver and Kleinpell,

California Univ. Pubs. Geol. Sci. Bull., v. 43, p. 186,

pi. 24, fig. 7. 

1969. Calyptraea diegoana (Conrad). Hickman, Oregon

Univ. Mus. Nat. History Bull. 16, p. 79, 82, pi. 11,

figs. 7, 8.

Type. USNM 1856 (designated by Keen and 

Bentson, 1944).

Type locality. San Diego, Calif. Eocene.

Calyptraea diegoana is a variable species characterized by a high, pointed spire and an excentric 

apex. The lectotype (Keen and Bentson, 1944, p. 

204) is an immature specimen almost as high as it 

is broad. Specimens from the Wygal Sandstone 

Member of the Temblor Formation have a straightsided to somewhat convex profile and little, if any, 

constriction of the shell wall at the suture. In lateral 

aspect, the narrowly excentric side of the shell is 

slightly convex whereas the broadly excentric side 

is relatively much flatter and even somewhat concave on certain specimens.

Stewart (1927) synonymized several names applied to this early Tertiary taxon, which is widespread in and characteristic of strata of Eocene 

age but which also occurs in Oligocene strata of 

Oregon and Washington (Hickman, 1969). The 

highest stratigraphic occurrence of this species is 

in the upper Oligocene, lower part of the "Blakeley 

Stage" of western Washington (Tegland, 1933; 

Durham, 1944), a unit with which the fauna of the 

Wygal Sandstone Member is believed to be coeval.

Calyptraea mammilaris vancouverensis Clark and 

Arnold (1923, p. 167, pi. 36, figs. 3a, 3b) from the 

Sooke Formation of southwestern Vancouver Island, 

British Columbia, differs from C. diegoana by its 

very thick, evenly and more highly conical shell and 

more or less centrally located apex. The California 

early Miocene species C. coreyi Addicott (1970a, p. 

60-61, pi. 4, figs. 1, 4, 18) that is also characterized by an eccentric apex and a moderately high 

spire can be distinguished from C. diegoana by its 

shouldered whorl profile.

Localities. USGS M3280, M3281, M4471.

Crepidula cf. C. ungana Dall

Plate 8, figures 6, 7, 9, 11, 15, 16

Specimens of thin-shelled Crepidula in the collections are similar to the Alaska Oligocene species 

C. ungana Dall (1904, p. 118, pi. 10, figs. 8, 9) from 

the Aleutian Islands. They have been compared with 

the type specimens (USNM 164918) and with a 

large suite of topotypes from Unga Island (USGS 

loc. 2103). The California specimens differ slightly 

from the types, an incomplete chain consisting of 

three specimens, in having a relatively finer, less 

swollen beak. The orientation of the beaks is similar more or less parallel to the plane of the aperture. On some of the topotypes of C. ungana, however, the beak tends to point upwards. A comparable 

upward orientation has been found on only one of 

the specimens from the basal sandstone member of 

the Temblor Formation. As noted by Hickman 

(1969, p. 82), specimens preserved in colonial form 

are more highly arched and narrower than those 

that occur as individual specimens.

The configuration and size of the internal septum 

of Crepidula cf. C. ungana is unknown. Viewed 

aperturally, the insertion of the septum is near the 

middle of the left side of the aperture as on C. 

ungana, which has an open S-shaped septal margin. 

The point of insertion on the opposite side of C. 

cf. C. ungana has not been observed.

Crepidula cf. C. ungana can be distinguished from 

the early Miocene species C. sookensis Clark and 

Arnold (1923) from Vancouver Island, British 

Columbia, and the northwestern Olympic Peninsula 

(Durham, 1944) by its much thinner and narrower 

shell and more delicate, less swollen beak. The septal 

configuration of specimens of C. sookensis from the 

Sooke Formation (USGS loc. M4060) is similar to 

that of the variable early Miocene to Holocene C. 

princeps Conrad.

Occurrences of Crepidula ungana in the conterminous Pacific Coast States range from the middle 

Oligocene "Lincoln Stage" (Hickman, 1969) to the 

late Oligocene lower part of the "Blakeley Stage" 

(Tegland, 1933; Durham, 1944).

Localities. USGS M3280, M3281, M3979.

Family NATICIDAE

Poorly preserved naticids on which it has not 

been possible to expose the umbilical area occur in 

the collections from USGS localities M3280, M3578, 

M3772, M3978, M3979, M4466, and M4468. The size 

and whorl profiles of these suggest either Natica 

or Polinices.
SYSTEMATIC DESCRIPTIONS 19

Genus NATICA Scopoli, 1777 

Subgenus NATICA s. s.

Natica (Natica) n. sp. 

Plate 8, figures 12, 13

At least five specimens of a moderately large, 

heavy-shelled Natica from USGS locality M3280 

represent an undescribed species. They differ from 

known middle Tertiary species of Natica in their 

relatively large adult size, widely open umbilicus, 

and heavy funicular rib. These specimens are too 

poorly preserved to permit formal description as a 

new species: most of the surface of the shells is 

missing, and the spire is incompletely preserved.

There are distinct similarities to the middle Tertiary species Natica teglandae Hanna and Hertlein 

(1938, p. 108) and N. vokesi Addicott (1966, p. 

638-639, pi. 77, figs. 2-5), but both of these small 

species have shouldered body whorls and only weakly 

or very weakly developed funicular ribs. The middle 

Miocene species N. posuncula Hanna and Hertlein 

(1938, p. 107-108, pi. 21, fig. 6) from the Kern 

River area on the southeastern margin of the San 

Joaquin basin has a similar profile but a narrow 

umbilical area that is filled by a relatively larger 

and broader funicular rib.

Natica s. s. is a warm-water genus restricted to 

the modern Surian and Panamic molluscan provinces of Valentine (1966) of the Pacific coast. Its 

occurrence in the fauna from the Wygal Sandstone 

Member of the Temblor Formation is suggestive of 

much warmer marine temperatures during the late 

Oligocene than occur along this part of the Pacific 

coast today.

Locality. USGS M3280.

Genus NEVERITA Risso, 1826 

Snbgenus GLOSSAULAX Pilsbry, 1929

Neverita (Glossaulax) thomsonae Hickmau

Plate 9, figure 4

1969. Neverita (Glossaulax) thomsonae, Hickman, Oregon 

Univ. Mus. Nat. History Bull. 16, p. 84, pi. 11, 

figs. 20-23.

1972. Neverita thomsonae Hickman. Addicott, Soc. Econ. 

Paleontologists and Mineralogists, Pacific Sec., 

Bakersfield, Calif., 1972, Proc., pi. 1, fig. 10. 

Types. Holotype, UO 27366; paratypes, UO 

26367-26370, 27371, 27372.

Type locality. UO 2567, northwestern Oregon. 

Pittsburg Bluff Formation, Oligocene.

As noted by Hickman (1969), this large species 

is very close to the living Neverita recluziana, a 

warm-water species that ranges from the west coast 

of Mexico to southern California (Smith and Gordon, 1948; Keen, 1971). The extremely large body 

whorl of N. thomsonae, which has a smooth, flattened profile, is the principal morphologic feature

used to differentiate the two species. N. thomsonae 

seems most closely related, morphologically, to the 

large form of N. recluziana figured by Pilsbry 

(1929, pi. 6, fig. 1) and differs from it, as noted by 

Hickman (1969), in having a relatively broader 

body whorl.

Neverita thomsonae differs from N. andersoni 

(Clark), a common species in early Miocene to 

Pliocene molluscan assemblages from California 

(Addicott, 1970a), in having a flattened, nonshouldered profile. The range of this species is from the 

middle to the upper Oligocene.

Locality. USGS M3978.

Genus POLINICES Montfort, 1810

Polinices n. sp.? 

Plate 9, figure 10

A moderately large Polinices which has a widely 

open umbilical area was collected from USGS localities M3280 and M4472. The heavy parietal callus 

thins and tapers uniformly toward the base of the 

aperture. The body whorl does not appear to be 

shouldered.

This species differs from Polinices victoriana 

Clark and Arnold (1923, p. 170, pi. 33, figs, la, Ib, 

5a, 5b) and P. canalis Moore (1963, p. 28, pi. 2, 

figs. 18, 20), Miocene species from the Pacific coast, 

in having a much larger, widely open umbilical area 

and a relatively narrow, but equally heavy, parietal 

callus. Natica n. sp.? Hickman (1969, p. 83-84, pi. 

10, figs. 15, 16) from the early and middle Oligocene 

Eugene Formation of Oregon has a much narrower 

umbilical opening and lacks the heavy parietalumbilical callus.

Localities. USGS M3280, M4472.

Genus S1NUM Roding, 1798

Sinum cf. S. scopulosum (Conrad)

Plate 9, figures 16, 17

Two internal molds from USGS locality M3578 

seem to represent Sinum scopulosum (Conrad, 1849, 

p. 727, pi. 19, figs. 6, 6a), an upper Oligocene to 

Holocene species. The fine spiral sculpture is faintly 

preserved on both specimens. Sinum scopulosum is 

distinguished from the Eocene and Oligocene species, 

S. obliquum (Gabb, 1864, p. 109, pi. 21, fig. 112), 

by its larger adult size and less flattened shell.

The lowest stratigraphic record of this species is 

from the upper Oligocene Echinophoria rex Zone 

(lower part of the "Blakeley Stage") of the northern Olympic Peninsula, Wash. (Durham, 1944), a 

unit that is believed to be coeval with the fauna of 

the Wygal Sandstone Member.

Localities. USGS M3578, M4471?.
20 MOLLUSCAN BIO STRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

Family FICIDAE 

Genus FICUS Roding, 1798

Ficus cf. F. modesta (Conrad) 

Plate 9, figures 18, 19

Two crushed specimens of a delicately ornamented 

Ficus are compared with F. modesta (Conrad, 

1848, p. 433, fig. 12), an Oligocene and Miocene 

species from the Pacific coast. This species differs 

from the middle Oligocene species Ficus (Trophosycon) gesteri Wagner and Schilling (1923, p. 258, 

pi. 49, figs. 1-3) from the nearby San Emigdio 

Mountains in lacking nodes on the shoulder of the 

body whorl. There is no evidence of nodes on the 

body whorl of the larger of the two specimens (pi. 

9, fig. 19).

Ficus modesta was recorded by Wagner and 

Schilling (1923, p. 246, as F. pyriformis Gabb) 

from the upper part of their Pleito Formation in 

the San Emigdio Mountains, a unit that is believed 

to be coeval with the Wygal Sandstone Member of 

the type Temblor Formation. It is also recorded 

from the San Ramon Sandstone of the Mount Diablo 

area, California.

Ficus modesta ranges from the middle Oligocene 

"Lincoln Stage" (Hickman, 1969) to the middle 

Miocene "Temblor Stage" (Schenck and Keen, 1940; 

Moore, 1963).

Localities. USGS M3578, M3978.

Order NEOGASTROPODA 

Family NEPTUNE1DAE

Genus CALICANTHARUS Clark, 1938

Calicantharus, an early Tertiary to Quaternary 

genus, is similar to Searlesia, a genus that occurs 

in temperate and cool-water molluscan provinces 

along the Pacific coast. Although reassignment of 

the following two species to Calicantharus constitutes the initial recognition of this genus in the late 

Oligocene of the Pacific coast, the genus is known to 

occur in the Eocene Markley Sandstone Member of 

the Kreyenhagen Formation of central California. 

Calicantharus is here discriminated from Searlesia 

on the basis of its collared or clasping suture.

Calicantharus dalli (Clark)

Plate 9, figure 24

1918. Searlesia dalli Clark, California Univ. Pubs., Dept. 

Geology Bull., v. 11, no. 2, p. 175, pi. 20, figs. 5, 

9, 15.

Types. Holotype, UCMP 11215; paratypes, 

UCMP 11214, 11214a.

Type locality. UCMP 2754, branch of San Pablo 

Creek on Sobrante Ridge, 1% miles northeast of 

California and Nevada Railroad, lat 37°56'54" N., 

long 122°14'01" W. Altitude 350 feet. San Ramon 

Sandstone, early Miocene (?).

Specimens of Calicantharus from USGS localities M3280 and M3772 are conspecific with Clark's 

(1918) C. dalli from the Mount Diablo area, Contra 

Costa County, Calif. C. dalli is larger than the type 

specimens but has the fine, channeled spiral ribbing, 

the sutural overlap, and the evenly convex whorl 

profile characteristic of this species. Moreover, the 

spire appears to bear very fine nodes at the point 

of greatest whorl convexity. The principal difference 

from Clark's (1918) types is the relatively greater 

size attained by the late Oligocene specimens from 

the Temblor Range.

Calicantharus dalli is quite distinct from Pacific 

coast Miocene species of this genus. Compared to 

specimens of C. branneri (Clark and Arnold, 1923, 

p. 159, pi. 30, figs. 3a, 3b), an equally large species 

from the Sooke Formation of southwestern British 

Columbia (USGS loc. M2544), it differs in having 

a broader body whorl, finer spiral sculpture, and 

virtually no angulation on the body whorl. C. kernensis (Anderson and Martin, 1914, p. 78-79, pi. 4, 

figs. 6a, 6b), a middle Miocene species from the 

California Coast Ranges, is characterized by a sinuous, rather than relatively straight, growth line and 

much narrower shell. Another middle Miocene species from central California, C. woodfordi Addicott 

(1970a, p. 93-94, pi. 10, fig. 6, pi. 11, figs. 17, 18), 

is of similar size of C. dalli but has very strongly 

angulated, noded whorls.

Localities. USGS M3280, M3772.

Calicantharus cf. C. branneri (Clark and Arnold) 

Plate 9, figure 13

An incomplete specimen from USGS locality 

M4471 is identical to Clark and Arnold's (1923, p. 

159, pi. 30, figs. 3a, 3b) species from the Sooke 

Formation of southwestern Vancouver Island, 

British Columbia. The body whorl is characterized 

by rounded spiral ribs that are separated by rather 

deep interspaces containing a fine intercalary riblet. 

As on the holotype, the axial folds are irregularly 

spaced and almost obsolete on the abapertural side 

of the body whirl.

This taxon differs from specimens of Calicantharus dalli (Clark) from the Wygal Sandstone 

Member in having high, rounded spiral ribs rather 

than relatively broad, straplike ribs separated by 

channeled interspaces.

The subsutural collar of this species indicates 

assignment to Calicantharus rather than Searlesia 

to which it was originally assigned (Clark and 

Arnold, 1923).

Locality. USGS M4471.
SYSTEMATIC DESCRIPTIONS 21

Genus KELLETIA Fischer, 1884 

Kelletia? sp.

Plate 9, figures 7, 11, 12

Two incomplete specimens of a moderately large 

neptuneid may represent the Eocene (Ruth, 1942) 

to Holocene genus Kelletia. The spiral sculpture of 

fine, flattened ribs separated by deeply channeled 

interspaces and the development of nodes on the 

whorl angulation are similar to late Cenozoic species 

of Kelletia described from California. The two specimens differ considerably in details of spiral and axial 

ribbing but are tentatively taken to represent a 

variable species. One specimen (pi. 9, figs. 11, 12) 

has relatively broad, straplike ribs that bear a 

medial groove; the other (pi. 9, fig. 7) has much 

finer spiral ribs, only a few of which bear a medial 

groove. The axial folds are very prominent on the 

penultimate whorl of one specimen (pi. 9, figs. 11, 

12) but are very weak on the other one (pi. 9, fig. 

7). Both specimens have a relatively broad apical 

angle and a moderately strong angulation near the 

middle of the whorls.

Localities. USGS M3280, M3772.

Genus SIPHONALIA Adams, 1863

Siphonalia? sp. 

Plate 9, figures 5, 6

A small, crushed specimen from USGS locality 

M3280 may represent Siphonalia. However, the 

generic assignment of this neptuneid is doubtful. 

The body whorl is constricted and apparently 

twisted to form a distinctive anterior canal very 

much like specimens of this genus figured by Ruth 

(1942). However, Siphonalial sp. differs from 

Oligocene and Miocene species included in Ruth's 

monograph in having only one row of very weakly 

developed nodes on the whorls of the spire. 

Locality. USGS M3280.

Genus BRUCLARKIA Stewart, 1927

Bruclarkia seattlensis Durham 

Plate 9, figures 1, 2, 8, 9, 14

1944. Bruclarkia seattlensis Durham, California Univ. 

Pubs., Geol. Sci. Bull., v. 27, no. 5, p. 173-174, pi. 

16, fig. 15.

1972. Bruclarkia seattlensis Durham. Addicott, Soc. Econ. 

Paleontologists and Mineralogists, Pacific Sec., 

Bakersfield, Calif., 1972, Proc., pi. 1, figs. 8, 13.

Type. UCMP 35397.

Type locality. UCMP A1803, behind the Olympic 

Foundry, Georgetown, Seattle, King County, Wash. 

Blakeley Formation, Oligocene.

Bruclarkia seattlensis is the most abundant gastropod in assemblages from the Wygal Sandstone 

Member. Many of the specimens are heavily encrusted with the bryozoan Antroporal sp. (O.L. 

Karklins, written commun., January 1971). Earlier 

identifications of B. barkeriana (Cooper) from exposures of the Wygal Sandstone Member (the socalled Phacoides reef) in the vicinity of Zemorra 

Creek (Kleinpell, 1938; Stinemeyer and others, 

1959; Foss and Blaisdell, 1968) are almost certainly 

of this species.

Specimens from the Wygal Sandstone Member 

differ slightly from the type of Bruclarkia seattlensis in having a somewhat stronger subsutural collar 

and in lacking fine nodes on the whorls of the spire. 

The form and sculptural detail of the body whorl, 

however, is the same: a faint angulation devoid of 

nodes and spiral sculpture of fine ribs that alternate in strength. Moore (1963, p. 36) showed that 

both the strength of the subsutural collar and the 

presence or absence of nodes are highly variable 

morphologic characters on Miocene species of Bruclarkia. Variation within B. seattlensis was previously unknown because this species was known 

only from the holotype.

This species very closely resembles the early and 

middle Miocene species Bruclarkia santacruzana 

(Arnold, 1908, p. 379-380, pi. 34, fig. 7), a smooth, 

strongly collared gastropod that has recently been 

treated as a form of the common middle Miocene 

species, B. barkeriana (Addicott, 1970a). Bruclarkia seattlensis differs from B. barkeriana forma 

santacruzana (pi. 9, fig. 3) in having a consistently 

much higher spire, a smooth collar that has no nodes, 

and, usually, a perceptibly angulated body whorl. 

Yet the morphologic similarities to B. santacruzana 

are so striking that B. seattlensis is very likely a 

direct precursor of the Miocene species. Durham 

(1944, p. 173-174) commented on the close degree 

of similarity of B. seattlensis to the middle Oligocene B. columbiana, and this similarity may imply 

an ancestral relationship.

Other species of Bruclarkia of common occurrence 

in formations of Oligocene age in the southern part 

of the San Joaquin basin (Wagner and Schilling, 

1923, p. 244, 248) can be readily distinguished from 

B. seattlensis. B. acuminata (Anderson and Martin, 

1914, p. 73, pi. 5, figs. 4a, 4b) has strongly noded, 

angulated whorls and either no subsutural collar or 

a very weak one.

Bruclarkia gravida (Clark, 1918, p. 182-183, pi. 

19, figs. 1, 3, 5) is likewise a strongly sculptured 

species on which there are three equally spaced rows 

of heavy, rounded nodes, the uppermost of which is 

born relatively high on the body whorl (pi. 9, figs. 

15, 20, 21). The possibility that B. seattlensis is a 

weakly sculptured form of B. gravida and might
22 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

bear a relationship similar to that between B. barkeriana forma santacruzana and B. barkeriana 

(Addicott, 1970a) seems unlikely in view of the 

relatively low position of the angulation on the body 

whorl of specimens of B. seattlensis from the Wygal 

Sandstone Member. The position of this angulation 

is closer to that of the Oligocene B. columbiana 

(Anderson and Martin, 1914, p. 73, pi. 5, figs. 6a, 

6b), an index species for the Refugian Stage. B. 

columbiana differs, however, in usually having a 

low spire that has a flat profile, a weak collar, and 

a long and concave subsutural segment on the body 

whorl terminating in a strongly noded angulation.

Some of the. smooth forms of the Early and Middle Miocene species Bruclarkia oregonensis (Conrad) are of similar size and sculptural aspects to B. 

seattlensis, but the subsutural collar on this species 

is very subdued, if developed at all, and the upper 

part of the body whorl tends to be convex rather 

than concave (Etherington, 1931, pi. 11, figs. 1, 3, 

4, 5, 7).

This is the only known record of Bruclarkia seattlensis from California. Prior to its discovery in 

the Wygal (Addicott, 1973), it was known only 

from the type locality near Seattle, Wash., where 

it occurs with a diverse molluscan assemblage referable to the upper Oligocene Echinophoria rex 

Zone of the "Blakeley Stage" (Durham, 1944).

Localities. USGS 5149, M3280, M3578, M3636, 

M3772, M3978, M3979, M4470, M4471.

Class PELECYPODA 

Order NUCULOIDA 

Family NUCULIDAE

Genus ACILA Adams and Adams, 1858 

Subgenus TRUNCAC1LA Grant and Gale, 1931

Acila (Truncacila) mnta Clark

Plate 1, figures 4, 15 

1918. Acila muta Clark, California Univ. Pubs., Dept.

Geology Bull., v. 11, no. 2, p. 119-120, pi. 13, figs.

6, 12, 13. 

1918. Acila muta var. markleyensis Clark, California Univ.

Pubs., Dept. Geology Bull., v. 11, no. 2, p. 121, pi.

13, fig. 3. 

1936. Acila (Truncacila) muta B. L. Clark. Schenck, Geol.

Soc. America Spec. Paper 4, p. 74-75, pi. 8 (figs.

4, 11; text fig. 7, nos. 20, 21.

Types. Holotype, UCMP 11196; paratypes, 

UCMP 11199, 11200.

Type locality. UCMP 1131, i/2 mile southwest of 

Walnut Creek, Contra Costa County, Calif., in 

creekbed about 100 yards east of Oakland and Antioch bridge. Altitude 150 feet. San Ramon Sandstone, 

early Miocene (?).

Two specimens of Acila from the Wygal Sandstone Member are identified as A. muta Clark, a

species heretofore known only from the San Ramon 

Sandstone near Mount Diablo, Contra Costa County, 

Calif. The outline of the valves and details of surface sculpture agree closely with dark's (1918, pi. 

13, figs. 6, 12, 13) types.

As indicated by Schenck (1936), the species that 

most closely resembles Acila muta is the middle 

Miocene A. conradi from the Temblor Formation 

("Temblor Stage") of California and from the 

Astoria Formation of Oregon and Washington. 

Schenck differentiated these two species on the relatively greater thickness of the valves of A. muta. 

They are differentiated here by the significantly 

smaller angle of bifurcation of A. muta evident from 

Clark's (1918) and Schenck's (1936) illustrated 

specimens. This difference is reflected by the fact 

that the primary line of bifurcation on specimens 

of A. conradi intersects the ventral margin in a 

more anterior position than on specimens of A. muta.

Two fragmentary specimens of Acila from USGS 

localities M3280 and M3579 are doubtfully referred 

to this species on the basis of similar radial sculpture and what appears to be a similarly oriented 

primary line of bifurcation. One of these specimens 

(USGS loc. M2380) is intensely deformed.

Localities. USGS M3280?, M3579?, M4466, 

M4471.

Family NUCULANIDAE

Genus YOLDIA Moller, 1842

Subgenus KALAYOLDIA Grant and Gales, 1931

Yoldia (Kalayoldia) tenuissima Clark

Plate 1, figures 2, 3, 5, 8 

1869. Yoldia cooperii Gabb. Gabb, California Geol. Survey,

Paleontology, v. 2, sec. 1, pt. 1, p. 31, pi. 9, fig. 4

[not Yoldia cooperii Gabb, 1865, California Acad.

Sci. Proc., 1st ser., v. 3, p. 189]. 

1918. Yoldia cooperi var. tenuissima Clark, California Univ.

Pubs., Dept. Geology Bull., v. 11, no. 2, p. 125-126,

pi. 11, fig. 10, pi. 12, figs. 8, 14. 

1925. Yoldia tenuissima Clark. Clark, California Univ.

Pubs. Geol. Sci., v. 15, no. 4, p. 78-79, pi. 8, figs.

5, 9.

1930. Yoldia cooperii Gabb subsp. supramontereyensis 

Arnold. Stewart, Acad. Nat. Sci. Philadelphia Spec. 

Pub. 3, p. 62-64 [in part], pi. 15, fig. 2.

1931. Yoldia (Portlandia) oregona (Shumard). Etherington, California Univ. Pubs., Dept. Geol. Sci. Bull., 

v. 20, no. 5, p. 67, pi. 1, fig. 8.

1942. Yoldia (Portlandia) oregona (Shumard). Weaver, 

Washington Univ. [Seattle] Pubs. Geology, v. 5, 

p. 49 [in part], pi. 9, fig. 8.

1963. Yoldia tenuissima Clark. Kleinpell and Weaver, California Univ. Pubs. Geol. Sci., v. 43, p. 196, pi. 28, 

fig. 4.

1969. Yoldia (Kalayoldia) tenuissima (Clark). Hickman, Oregon Univ. Mus. Nat. History Bull. 16, p. 32-33, pi. 

1, fig. 18.
SYSTEMATIC DESCRIPTIONS 23

Types. Holotype, UCMP 11110; paratypes, 

UCMP 11163 and 11170.

Type locality UCMP 798, lat 37.2° N., long 

122.1° W. San Ramon Sandstone, early Miocene (?) 

(no other data in the University of California 

locality register).

Specimens of Yoldia tenuissima from the Wygal 

Sandstone Member of the Temblor Formation are 

of uniform size and morphology; the unibo is situated posteriorly to the middle of the valve. In the 

similar Oligocene species from Oregon, Y. oregona 

(Shumard, 1858), the umbo is centrally located, or 

nearly so. Hickman (1969, p. 32) carefully considered the morphologic differences between these species. Another middle Tertiary species that has been 

included with Y. tenuissima by Stewart (1930, p. 

63), Y. supramontereyensis Arnold (1908, p. 382, 

pi. 35, fig. 9) from middle Miocene strata near Stanford University, California, has a medially situated 

umbo and a deeply concave posterior dorsal margin. 

These characters seem to permit differentiation 

from Y. tenuissima.

The earliest occurrence of this species is in rocks 

of Oligocene age. It was used to name a molluscan 

subzone of the Refugian Stage in the western Santa 

Ynez Mountains by Kleinpell and Weaver (1963). 

It also commonly occurs in the upper part of the 

San Emigdio Formation (Wagner and Schilling, 

1923; DeLise, 1967) in strata that are at least in 

large part referable to the Acila shumardi Zone of 

the Refugian Stage of Schenck and Kleinpell (1936) 

and the "Lincoln Stage" of Weaver and others 

(1944). Yoldia tenuissima is also recorded from the 

northern part of the Diablo Range (Clark, 1918, 

1925; Weaver, 1949; Primmer, 1964). Hickman 

(1969) summarized Oligocene occurrences in Oregon and Washington and also assigned to this species a middle Miocene specimen from the Astoria 

Formation (Etherington, 1931, pi. 1, fig. 8) that 

had previously been assigned to Y. temblorensis by 

Trumbull (1958). Some specimens of middle Miocene age from the Kern River area, California 

(Addicott, 1956), also seem to represent Y. tenuissima. A specimen from a locality near the base of 

the Round Mountain Silt is figured in this report 

(pi. 1, fig. 8). Another specimen from about the 

same stratigraphic position in the Olcese Sand (pi. 

1, fig. 12), characterized by a uniquely short posterior dorsal slope and a posteriorly situated beak, 

may represent Clark's (1915, p. 446, pi. 48, fig. 6) 

Y. carnarosensis from the San Pablo Formation, 

Napa County, Calif.

Fragments of a large Kalayoldia from the Salt 

Creek Shale of Foss and Blaisdell (1968) (UCR

loc. 1106) seem to represent a different species because they are relatively larger and more coarsely 

ribbed than specimens of Y. tenuissima from the 

overlying Wygal Sandstone Member. They also have 

medially located beaks, unlike Y. tenuissima. These 

fragments might represent Y. oregona.

Localities. USGS 9432, M3578, M3636?, M3978, 

M4466, M4468?; UCR 1235.

Order ARCOIDA

Family ARC1DAE

Genus ANADARA Gray, 1847

Subgenus ANADARA *. s.

Anadara (Anadara) iubmontereyana (Clark)

Plate 1, figures 6, 7, 11, 16, 17

1918. Area (Scapharca) submontereyana Clark, California 

Univ. Pubs., Dept. Geology Bull., v. 11, no. 2, p. 

128-129, pi. 16, fig. 2.

1938. Anadara (Anadara) mediaimpressa var. submontereyana (Clark). Schenck and Reinhart, Mus. Royal 

Histoire Nat. Belgique Mem., ser. 2, no. 14, p. 38.

1943. Anadara (Anadara) mediaimpressa subsp. montereyana (Clark). Reinhart, Geol. Soc. America Spec. 

Paper 47, p. 40-41, pi. 4, fig. 7.

1972. Anadara submontereyana (Clark). Addicott, Soc. 

Econ. Paleontologists and Mineralogists, Pacific Sec., 

Bakersfield, Calif. 1972, Proc., pi. 1, fig. 7.

Types. Holotype, UCMP 11186; paratype, 

UCMP 11186A.

Type locality. UCMP 52, near top of first ridge 

west of Walnut Creek, 1^4 miles south of Walnut 

Creek, Contra Costa County, Calif. Long 122°1'39" 

W., lat 37°52'44" N. Altitude 350 feet. San Ramon 

Sandstone, early Miocene?.

Representatives of this species from localities 

near the base of the type section of the Temblor 

Formation are characterized by about 23 broad, 

flat-topped ribs that are generally wider than the 

interspaces, particularly on the posterior part of 

the valves. The number of ribs varies from as few 

as 21 or 22 to as many as 25. Both the ribs and 

interspaces are seen to be very finely noded on a few 

of the better preserved specimens. The Wygal specimens differ from the types principally by their relatively larger size. As noted by Reinhart (1943), 

the beaks are located about one-third of the distance 

from the anterior extremity of the valves.

Although the only reported occurrences of this 

species is from the type locality in the San Ramon 

Sandstone near Walnut Creek, Calif., poorly preserved minute specimens of an unnamed species 

from rocks of probable late Oligocene age in the 

Santa Lucia Range (SU type colln. 7574) are very 

similar to this species. They have been compared 

with Anadara strongi (Loel and Corey) (Reinhart, 

1943, p. 43). The unnamed species is from rocks 

mapped as Vaqueros Formation by Edwards (1940)
24 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

that contain Pecten sanctaecruzensis Arnold, a pectinid whose presence implies correlation with the 

Wygal Sandstone Member of the Temblor Formation 

and with strata assigned to the lower part of Kleinpell's (1938) Zemorrian Stage. A. submontereyana 

differs from A. strongi, a somewhat similar species 

of early Miocene age, in having a few more radial 

ribs that are not strongly grooved.

Poorly preserved specimens of Anadara from 

USGS localities M4466 and M4469 in the Wygal 

Sandstone Member may represent A. submontereyana but are specifically indeterminate.

Localities. USGS 5149 cf., M3280, M3281, 

M3578, M3579, M3772, M3978.

Order MYTILOIDA

Family MYTILIDAE

Genus CRENOMYTILUS Soot-Ryen, 1955

Crenomytilus ? cf. C. ? arnoldi (Clark) 

Plate 1, figures 1, 18; plate 3, figure 2

A large mytilid characterized by thin valves and 

a broad umbonal angle is similar to Crenomytilus 

arnoldi (Clark, 1918, p. 135, pi. 12, fig. 1), an Oligocene species from the Kirker Tuff near Mount 

Diablo, Calif. Unfortunately, all the specimens from 

the Wygal Sandstone Member are strongly deformed 

and broken, but they differ from Clark's species 

principally in size they are more than twice the 

height of the holotype of C. arnoldi. The smaller 

specimens, however, seem almost indistinguishable 

from the holotype. They also resemble a form of 

the large early to middle Miocene species C. expansus (Arnold, 1907, p. 528, pi. 43, fig. 2). Although 

the umbonal angles are similar, the late Oligocene 

specimens from the Wygal Sandstone Member lack 

the finely striated surface characteristic of C. expansus. Another large species from the lower Miocene "Vaqueros Stage" of California, C. loeli 

(Grant), differs from these specimens in having a 

strongly concave rather than straight ventral 

margin.

Poorly preserved, incomplete mytilids from USGS 

localities M4466, M4469, M4470, and M4472 may 

represent this taxon.

Assignment of these specimens to Crenomytilus, 

an extinct middle and late Tertiary genus from the 

North Pacific rim is doubtful because details of the 

resilial ridge and shell margins are unknown. It is, 

however, very similar to Tertiary species from the 

Pacific coast assigned to this genus by Soot-Ryen 

(1955).

Crenomytilus arnoldi is reported from several 

Oligocene formations in California: the Kirker Tuff 

and the San Ramon Sandstone of the Mount Diablo

area (Clark, 1918; Weaver, 1949; Primmer, 1964), 

the upper part of the San Emigdio Formation and 

the lower part of the Pleito Formation of the San 

Emigdio Mountains (Wagner and Schilling, 1923), 

and the San Juan Bautista Formation of the northern end of the Gabilan Range (Schenck in Alien, 

1945).

Localities. USGS M3578, M3636 cf., M3978, 

M3979, M4468.

Crenomytilus expansus (Arnold)

Plate 4, figure 15

1907. Mytilus mathewsoni Gabb var. expansus Arnold, U.S. 

Natl. Museum Proc., v. 32, no. 1545, p. 528, pi. 43, 

fig. 2.

1907. Mytilus mathewsoni Gabb var. expansus Arnold. Arnold, U.S. Geol. Survey Bull. 309, pi. 30, fig. 2.

1909. Mytilus mathewsoni Gabb var. expansus Arnold. Arnold, U.S. Geol. Survey Bull. 396, pi. 5, fig. 3.

1910. Mytilus mathewsoni Gabb var. expansus Arnold. Arnold and Anderson, U.S. Geol. Survey Bull. 398, pi. 

27, fig. 3.

1932. Mytilus expansus Arnold. Loel and Corey, California 

Univ. Pubs., Dept. Geol. Sci. Bull., v. 22, no. 3, p. 

205, pi. 34, fig. 1.

Type. USNM 164968.

Type locality. Near Torrey Canyon oil wells, 

southwest of Piru, Ventura County, Calif. Vaqueros 

Formation, lower Miocene.

One specimen was collected from the Wygal Sandstone Member near Carneros Springs. It differs from 

Crenomytilus'! cf. C. arnoldi (Clark), a relatively 

common species in the Wygal, in having a recurved 

beak and a finely striated surface. This stratigraphic 

occurrence of C. expansus extends the range into 

the provincial upper Oligocene, previous records 

being from strata assigned to the lower Miocene 

"Vaqueros Stage" (Loel and Corey, 1932; Fritsche, 

1967; Adegoke, 1969). Fritsche (1967) suggested 

that C. expansus might be a synonym of C. coalingensis (Arnold, 1909, p. 73-74, pi. 19, fig. 5 and 

pi. 22, fig. 6), a Pliocene species from near Coalinga, 

Calif. Although the very strongly recurved and 

greatly thickened beak of C. coalingensis seem to 

distinguish it from C. expansus, the relationship of 

these two species certainly merits further study.

Locality. USGS 9427.

Order PTERIOIDA

Family PECTINIDAE

Genus PECTEN Muller, 1776

Suubgenus PECTEN s. >.

Pecten (Pecten) sanctaecruzensis Arnold

Plate 2, figures 4, 7 

1906. Pecten (Pecten) sanctaecruzensis Arnold, U.S. Geol.

Survey Prof. Paper 47, p. 54-55, pi. 3, figs. 12, 13. 

1909. Pecten (Pecten) sanctaecruzensis Arnold, U.S. Geol.

Survey Folio 163, illus. II, fig. 18.
SYSTEMATIC DESCRIPTIONS 25

1923. Pecten (Pecten) dickersoni Wagner and Schilling, 

California Univ. Pubs., Dept. Geol. Sci. Bull., v. 

14, no. 6, p. 253, pi. 45, fig. 1.

1940. Pecten dickersoni Wagner and Schilling. Schenck and 

Keen, California fossils for the field geologist, pi, 

28, fig. 1.

1972. Pecten sanctaecruzensis Arnold. Addicott, Soc. Econ. 

Paleontologists and Mineralogists, Pacific Sec., 

Bakersfield, Calif., 1972, Proc., pi. 1, fig. 2.

Types. Holotype, SU 360; paratype, SU 361.

Type locality. SU locality 111, Two Bar Creek, 

!/i mile above junction with San Lorenzo River, 

Santa Cruz County. Vaqueros Formation, about 600 

feet above base (Burchfiel, 1964, text fig. 2) ; late 

Oligocene. The paratype is from float collected in 

Bear Creek about 2 miles from the holotype locality.

Several disarticulated valves of Pecten sanctaecruzensis have been collected from exposures of a 

3-foot-thick Crassostrea-bearing sandstone bed at 

the base of the Wygal Sandstone Member in a tributary of Zemorra Creek (USGS loc. M4467). These 

specimens are similar to the type material from the 

Vaqueros Formation of the Santa Cruz Mountains 

(Arnold, 1906, p. 54-55, pi. 3, figs. 12, 13) except 

for their larger adult size.

Right valves of the pectinid range from about 45 

to 85 mm (millimeters) in length. They have 12 or 

13 strong ribs which have gently rounded upper surfaces and vertical sides. The interspaces are deep, 

relatively flat bottomed, and somewhat narrower 

than the ribs. On two of the larger specimens, there 

is a suggestion of fine radial sculpture on a few of 

the ribs.

Two left valves in the USGS collection from locality M4467 are relatively flat. The interior of the 

better preserved valve is characterized by strong 

cardinal crura that extend almost to the ligamental 

pit. Each valve has 12 prominent radial ribs that are 

much sharper than those of the right valve and 

that are separated by relatively wide interspaces. 

These valves measure about 48 and 73 mm long.

Pecten sanctaecruzensis is a potentially valuable 

species for stratigraphic correlation in California 

Coast Range basins. Its local stratigraphic range, 

or teilzone, and position in the provincial foraminiferal chronology are well known (Burchfiel, 1964). 

Although the record in the Wygal Sandstone Member is the first reported from east of the San Andreas fault, this species also occurs at a locality in 

the Pleito Formation of the San Emigdio Mountains. 

It was originally described from "a faulted block 

of the San Emigdio Formation on Salt Creek" by 

Wagner and Schilling (1923, p. 253, pi. 45, fig. 1) 

as Pecten dickersoni. Detailed mapping of this area

(Dibblee, 1961) shows that the type locality is in 

the Pleito Formation of Wagner and Schilling 

(1923), and study of several topotypes from USGS 

locality M3747 indicates that the pattern of ribbing 

and the number of ribs are identical to P. sanctaecruzensis. This Pecten occurs with an assemblage 

that is comparable to the fauna of the Wygal Sandstone Member and that has no species restricted to 

the Refugian Stage. The only other known occurrences are from the type area in the Santa Cruz 

Mountains (Arnold, 1906; Brabb, 1964; Burchfiel, 

1964) and from the Salinas Valley (Edwards, 1940). 

Both of these occurrences are in rocks mapped as 

Vaqueros Sandstone and assigned to the Zemorrian 

Stage of the foraminiferal chronology. It should be 

noted, however, that the Santa Cruz Mountains 

occurrence may be in strata generally older than 

the Vaqueros Sandstone of other areas in the California Coast Ranges. In fact, Arnold (1908, p. 349) 

originally noted that the fine-grained sandstones 

from which P. sanctaecruzensis was collected contained a faunal assemblage that appeared to be 

transitional between that of the San Lorenzo Formation below and his Vaqueros Sandstone above. 

He concluded that the assemblage resembled the 

fauna of the San Lorenzo more closely than that of 

his Vaqueros Sandstone; his Vaqueros fauna (Arnold, 1908, p. 350) consisted of assemblages that 

are referable to the present-day "Vaqueros" and 

"Temblor Stages" of Weaver and others (1944).

In addition to Arnold's (1908) molluscan evidence, benthonic foraminifers from his transitional 

fine-grained sandstones include at least one species, 

Cibicides pseudoungerianus evolutus (Brabb, 1964, 

p. 677) that is suggestive of an early Zemorrian 

age (Kleinpell, 1938, p. 140). As discussed in the 

section on provincial age and correlation, indications 

are that the fauna of the "Vaqueros Stage" corresponds to the upper part of the Zemorrian and 

lower part of the Saucesian Stages of the provincial 

foraminiferal chronology. The subsequent mapping 

of Arnold's (1908) transitional sandstone in the 

Vaqueros Sandstone (Brabb, 1964; Burchfiel, 1964) 

is not, therefore, indicative of an exclusively "Vaqueros" age for occurrences of Pecten sanctaecruzensis in the Santa Cruz Mountains.

The indicated cooccurrence of this species with 

foraminiferal assemblages of early Zemorrian age 

in the Santa Cruz Mountains and in the Temblor 

Range (Kleinpell, 1938) suggests that the lower 

part of the Vaqueros Sandstone of Brabb (1964) 

and Burchfiel (1964) is correlative with the Wygal 

Sandstone Member of the type Temblor Formation.

Locality. USGS M4467.
26 MOLLUSC AN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

Genus LEPTOPECTEN Verrill, 1897

Leptopecten? sp. 

Plate 1, figure 14

1972. Leptopectent sp. Addicott, Soc. Econ. Paleontologists 

and Mineralogists, Pacific Sec., Bakersfield, Calif., 

1972, Proc., pi. 1, fig. 11.

A fragment of a small pectinid from USGS locality M3280 is doubtfully identified as Leptopecten sp. 

on the basis of similarity of the ribbing pattern to 

L. andersoni (Arnold, 1906, p. 82-83, pi. 26, figs. 

5, 7), a widespread middle Miocene species from 

the California Coast Ranges. Eleven ribs are preserved on this incomplete specimen; they are 

V-shaped in cross section and rise to an angular 

crest. The interspaces contain microscopic growth 

lamellae that resemble those developed on specimens 

of L. andersoni from the so-called Barker's Ranch 

fauna of middle Miocene age along the southeastern 

margin of the San Joaquin basin. A more complete 

specimen from the lower part of the Santos Shale 

(Addicott, 1972, pi. 1, fig. 11; USGS loc. M3983) 

seems to represent this species.

Locality. USGS M3280.

Genus VERTIPECTEN Grant and Gale, 1931

Vertipecten alexclarki Addicott, n. sp.

Plate 1, figures 9, 10, 13; plate 2, figures 1, 3, 5, 8, 9; 

plate 3, figures 1, 4

1905. Pecten sp. Anderson, California Acad. Sci. Proc., 3d 

ser., v. 2, no. 2, p. 170.

1906. Pecten (Chlamys) branneri Arnold, U.S. Geol. Survey

Prof. Paper 47, p. 55-56 (in part), [not pi. 3,

figs. 9-11]. 

1972. Vertipecten n. sp. Addicott, Soc. Econ. Paleontologists

and Mineralogists, Pacific Sec., Bakersfield, Calif.,

1972, Proc., pi. 1, figs. 16, 18.

Moderately large, reaching as much as 115 mm 

in height, higher than long. Apical angle narrow, 

averaging about 70°. Right valve relatively flat; has 

20 to 30 or more flat-topped, scaly ribs that tend 

to be dichotomous in the central portion of the disk 

but more irregular in development toward the sides. 

Scales are fine and closely spaced near beak but become coarser and more widely spaced toward base. 

Secondary riblets usually developed in the interspaces between the paired ribs. Anterior auricle 

long, set off by deep byssal notch. Auricle sculptured 

by five strong ribs bearing heavy flanges. Left valve 

convex and has rather uniform sculpture of primary, 

secondary, and tertiary rounded ribs bearing strong, 

rather widely spaced flanges toward the base. Medial 

primary and two lateral primaries that tend to 

divide the disk into quadrants are somewhat 

stronger than other primary ribs.

This species is assigned to Vertipecten because of 

the distinct inequality of the valves, the right valve 

being relatively flat and the left being moderately 

convex (pi. 1, fig. 10), and because of the relatively 

greater strength of the central and two lateral primary ribs on the left valve, the three of which tend 

to divide the valve into quadrants. In sculptural 

detail and in the size of the right anterior ear, the 

species resembles Chlamys.

The right valve of Vertipecten alexclarki n. sp. 

is characterized by narrow, flat-topped ribs that are 

highly irregular in their development, whereas the 

left valve has a more or less orderly development of 

rounded primary, secondary, and tertiary ribs. The 

ribs of both valves are scaly.

This species seems to be a lineal antecedent of 

the early and middle Miocene species Vertipecten 

perrini (Arnold). The Miocene specifies differs, however, by having fewer, much coarser ribs on the 

right valve that also tend to be smooth and generally 

are not dichotomous. The medial portion of the right 

valve of V. perrini also has a depression coinciding 

with an interspace and reflecting a relatively much 

more strongly raised medial rib on the left valve.

The sculpture of the right valve of Chlamys branneri (Arnold, 1906, p. 55-56, pi. 3, figs. 9-11), a 

middle Miocene species from the eastern foothills 

of the Santa Cruz Mountains, is similar to that of 

the Vertipecten alexclarki. In fact, some workers 

(Kleinpell, 1938; Stinemeyer and others, 1959; Foss 

and Blaisdell, 1968) identified C. branneri from the 

Wygal Sandstone Member. Although the type material of C. branneri is poorly preserved, it is an 

equivalved species and, therefore, is properly assigned to Chlamys and not to the subsequently proposed genus Vertipecten, which is characterized by 

a relatively flat right valve and a convex left valve 

(see pi. 1, fig. 10). Other differences are the similar 

sculpture of both valves of C. branneri, the lack of 

an accentuated medial rib on the left valve, and the 

greater number of radial ribs on the auricles of that 

species 6 to 10 rather than 5. It is possible that a 

specimen, or specimens, identified by Arnold (1906, 

p. 56) as C. branneri from the lower part of what 

is now mapped as Vaqueros Sandstone (Brabb, 

1964) on Twobar Creek in the Santa Cruz Mountains, may represent V. alexclarki n. sp. The material is from rocks of approximately the same age. 

C. branneri, on the other hand, is from unnamed 

rocks of middle Miocene age from Coyote Hills near 

the Stanford University campus (Dibble, 1966).

This species is named for Alex Clark, who made 

extensive unpublished studies of Oligocene and 

Miocene mollusks of the southern part of the San
SYSTEMATIC DESCRIPTIONS 27

Joaquin basin for Shell Oil Co. during the 1930's 

(1931-1935, Department of Geology, California 

University, Riverside).

Localities. USGS 5149?, M3280, M3281, M3579, 

M3636, M3772, M3984, M3985, M4466, M4468, 

M4470, M4472.

Family OSTREIDAE 

Genus CRASSOSTREA Sacco, 1897

Crassostrea eldridgei ynezana (Loel and Corey)

Plate 2, figures 2, 10 

1907. Ostrea eldridgei Arnold. Arnold and Anderson, U.S.

Geol. Survey Bull. 322, pi. 18, figs. 6a, 6b. 

1932. Ostrea eldridgei (Arnold) var. ynezana Loel and 

Corey, California Univ. Pubs., Dept. Geol. Sci. Bull., 

v. 22, no. 3, p. 188-189, pi. 11, fig. 3; pi. 12, figs,, 

la-lc; pi. 13, figs. 1, 2a, 2b.

Type. UCMP 31745.

Type locality. UCMP A317. At west end of hill 

that is poorly defined on the topographic map about 

0.5 mile northwest of Rancho Atascoso house. 1.2 

miles S. 80° E. from 603-foot bench mark on road. 

Vaqueros Formation, early Miocene.

Specimens of Crassostrea eldridgei ynezana are 

characterized by their relatively thin valves, the left 

being moderately convex and somewhat larger than 

the right. The largest specimen is about 100 mm in 

height. During an early stage of growth the axis of 

the valve undergoes a gradual rotation through 

about 45°, the result being posteriorly situated beaks 

and, on many specimens, a subquadrate outline.

This species is similar to Crassostrea sookensis 

(Clark and Arnold, 1923, p. 138, pi. 17, figs. 1, 2) 

from the early Miocene (?) Sooke Formation of 

southern Vancouver Island, British Columbia. The 

northern species has a thicker shell in general and 

a less quadrate outline than specimens of C. eldridgei 

ynezana from the Wygal Sandstone Member. C. 

sookensis may represent a prior name for C. eldridgei ynezana, but the holotype is too poorly preserved to determine possible relationships confidently.

Fragments of a large, very thick shelled oyster 

from several localities in the Wygal Sandstone 

Member seem to represent a different species from 

Crassostrea eldridgei ynezana.

Localities. USGS M3280, M3578, M3772, M3978, 

M3979?, M4466?.

Crassostrea? sp.

Fragments of a large, very thick shelled ostreid 

occur commonly in exposures of the Wygal Sandstone Member, particularly in the coarse-grained 

basal sandstone. The fragments range from about 

15 to 25 mm thick; many are more than 100 mm

long. Judging from these dimensions and the heavy 

ligamental groove, these fragments represent Crassostrea. The listing of occurrences is by no means 

an accurate index of the occurrence of this ostreid 

in the Wygal Sandstone Member; specimens were 

observed in the field at almost every locality but, 

because of the indeterminate nature of the fragments, were not collected.

Localities. USGS 5149, M4467, M4468, M4470, 

M4472.

Order VENEROIDA

Family LUCINIDAE

Genus HERE Gabb, 1866

Here excavata (Carpenter)

Plate 3, figures 6, 8, 9 

1857. Lucina excavata Carpenter, Catalogue of the Reigen

Collection of Mazatlan Mollusca, in the British

Museum, p. 98. 

1866. Lucina (Here) Richthofeni Gabb, California Geol.

Survey, Paleontology, v. 2, sec. 1, pt. 1, p. 29, pi. 8,

figs. 49a, 49b.

1884. Lucina richthofeni Gabb. Tryon, Structural and systematic conchology, v. 3, p. 210, pi. 119, figs. 46, 53. 

1901. Phacoides (Here) richthofeni (Gabb). Ball, U.S. Natl.

Mus. Proc., v. 23, no. 1237, p. 810, 827, pi. 40, figs.

7,9.

1904. Phacoides richthofeni Gabb. Keep, West American 

shells, p. 58, fig. 45.

1905. Lucina richthofeni Gabb. Anderson, California Acad.

Sci. Proc., 3d ser., v. 2, no. 2, p. 170. 

1907. Phacoides richthofeni Gabb. Arnold, U.S. Natl. Mus.

Proc., v. 32, no. 1545, p. 543, pi. 45, fig. 4. 

1907. Phacoides richthofeni Gabb. Arnold, U.S. Geol. Survey

Bull. 309, p. 236, pi. 32, fig. 4. 

1911. Phacoides richthofeni Gabb. Keep, West coast shells,

p. 69, fig. 45. 

1915. Phacoides richthofeni Gabb. Clark, California Univ.

Pubs., Dept. Geology Bull. v. 8, no. 22, p. 419, pi.

62, fig. 2.

1930. Lucina (Here) excavata Carpenter. Stewart, Acad. 

Nat. Sci. Philadelphia Spec. Pub. 3, p. 181-182, pi. 

15, fig. 3, pi. 17, fig. 5.

1931. Lucina (Here) excavata Carpenter. Grant and Gale, 

San Diego Soc. Nat. History Mem., v. 1, p. 290- 

291, pi. 14, figs. 2, 5, 10.

1932. Phacoides (Here) richthofeni Gabb. Loel and Corey,

California Univ. Pubs., Dept. Geol. Sci. Bull., v. 22,

no. 3, p. 210, pi. 36, fig. 4. 

1935. Lucina (Here) richthofeni Gabb. Keep and Bailey,

West coast shells, p. 84, fig. 57. 

1958. Lucina (Here) excavata Carpenter. Keen, Sea shells

of tropical west America, p. 94, fig. 188. 

1966. Lucina excavata Carpenter. Brann, Illustrations to

"Catalogue of the Collection of Mazatlan shells"

by Philip P. Carpenter, p. 37, pi. 12, fig. 140. 

1969. Here (Here) excavata (Carpenter). Chavan, Treatise

on invertebrate paleontology, Part N, v. 2, p.

N496, fig. E3, la, Ib.

Type. British Museum (Palmer, 1958). 

Type locality. Mazatlan, Mexico. Holocene.
28 MOLLUSCAN BIOSTRATTGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

This small, strongly inflated lucinid is usually 

represented by articulated specimens. There is some 

variation in the degree of inflation of the valves 

and in the umbonal angle on specimens from the 

Wygal Sandstone Member. They are similar to, but 

somewhat more inflated than, specimens of middle 

Miocene age from the upper part of the Olcese Sand 

of the Kern River area on the southeastern margin 

of the San Joaquin basin.

Here excavata occurs commonly in rocks of Miocene and Pliocene age in California. Many of the 

occurrences are listed by Stewart (1930, p. 181). 

The species is one of the longest ranging Tertiary 

bivalves on the Pacific coast. Its earliest occurrence 

is in the middle Oligocene fauna of the San Emigdio 

Formation of Wagner and Schilling (1923) at the 

southern margin of the San Joaquin basin (Wagner 

and Schilling, 1923) where it occurs in the Acila 

shumardi Zone of the Refugian Stage of Schenck 

and Kleinpell (1936).

Localities. USGS 9432, M3280, M3578, M3579, 

M3978, M4466.

Genus LUCINOMA Dall, 1901

Lucinoma acutilineata (Conrad)

Plate 2, figure 6; plate 3, figures 3, 7

1849. Lucina acutilineata Conrad, U.S. Explor. Exped., 

Geology, v. 10, app. p. 725, atlas pi. 18, figs. 2, 

2a, 2b.

1849. Pectunculus patulus Conrad, U.S. Explor. Exped.,

Geology, v. 10, app. p. 726, atlas, pi. 18, figs. 8, 8a.

71857. Cyclas permacra Conrad, U.S. 33rd Cong., 2d sess.,

H. Ex. Doc. 91, no. 7, pt. 2, p. 192, pi. 6, fig. 6. 

1903. Lucina borealis Linnaeus. Yates, Southern Calif.

Acad. Sci. Bull., v. 2, no. 7, pi. 8, fig. 13. 

1909. Phacoides acutilineatus Conrad. Dall, U.S. Geol. Survey Prof. Paper 59, p. 116-117, pi. 12, fig. 6.

1909. Phacoides acutilineatus Conrad. Arnold, U.S. Geol. 

Survey Bull. 396, p. 122, pi. 8, fig. 4.

1910. Phacoides acutilineatus Conrad. Arnold and Anderson, U.S. Geol. Survey Bull. 398, p. 294, pi. 30, 

fig. 4.

1929. Phacoides acutilineatus (Conrad). Clark, Stratigraphy and faunal horizons of the Coast Ranges 

of California, pi. 23, fig. 7.

1931. Phacoides (Liicinoma) acutilineatus (Conrad). Etherington, California Univ. Pubs., Dept. Geol. Sci. 

Bull., v. 20, no. 5, p. 76-77, pi. 4, fig. 5.

1931. Lucina (Myrtea) acutilineata Conrad. Grant and 

Gale, San Diego Soc. Nat. History Mem., v. 1, 

p. 286-287 (in part), [not pi. 14, figs. 22a, 22b].

1932. Phacoides (Lucinoma} acutilineatus (Conrad). Loel

and Corey, California Univ. Pubs., Dept. Geol. Sci.

Bull., v. 22, no. 3, p. 211, pi. 36, fig. 3. 

1947. Lucinoma ac^ltilineata (Conrad). Stewart, U.S. Geol.

Survey Prof. Paper 205-C, pi. 15, fig. 9. [Imprint

1946.] 

1964. Lucinoma acutilineata (Conrad). Moore, U.S. Geol.

Survey Prof. Paper 419, p. 70-71, pi. 15, figs.

7-10, 12. [Imprint 1963.]

1969. Lucinoma acutilineata (Conrad). Hickman, Oregon 

Univ. Mus. Nat. History Bull. 16, p. 39-40, pi. 3, 

figs. 1, 4.

1972. Lucinoma acutilineata (Conrad). Addicott, Soc. Econ. 

Paleontologists and Mineralogists, Pacific Sec., 

Bakersfield, Calif. 1972, Proc., pi. 1, figs. 3, 15.

Type. USNM 3519 (designated by Woodring, 

1938).

Type locality. Astoria, Oreg. Astoria Formation, 

Miocene.

This is the species most characteristic of the basal 

sandstone member of the type Temblor Formation. 

It is very abundant at most localities, notably at 

USGS M3280. It was initially listed from the Wygal 

Sandstone Member by Anderson (1905, p. 170) as 

Lucina borealis.

Lucinoma acutilineata is characterized by regularly spaced, sharp concentric lamellae. The interspaces are packed with extremely fine concentric 

threads. The spacing of the primary lamellae is 

variable, as noted by Moore (1963). On a few specimens, these ribs are spaced twice as far apart as 

on others, almost as if alternate ribs had been 

omitted as the shell was being deposited (pi. 3, 

fig. 3).

Lucinoma acutilineata has its initial and lowest 

stratigraphic occurrence in rocks assigned to the 

middle Oligocene "Lincoln Stage" of western Oregon (Hickman, 1969). It ranges at least through 

the middle Miocene. Pliocene and Quaternary specimens that resemble L. acutilineata are generally 

identified as L. annulata (Reeve) on the basis of a 

somewhat longer posterior dorsal margin and a less 

strongly developed hinge which includes weaker 

anterior teeth (Tegland, 1933; Moore, 1963). The 

relative length of the posterior dorsal margin on 

specimens from USGS locality M3280 is variable 

(pi. 3, figs. 3, 7) owing, at least in part, to postburial deformation of the valves.

Localities. USGS 5149, 9432, M3280, M3578, 

M3579, M3636, M3772, M3978, M3979, M3984, 

M3985, M4466, M4468, M4469, M4470, M4471, 

M4472, M4473.

Genus M1LTHA Adams and Adams, 1857 

Miltha (Miltha) sanctaecrucis (Arnold)

Plate 3, figures 5, 10 

1910. Phacoides (Miltha) sanctaecrucis Arnold, U.S. Geol.

Survey Bull. 396, p. 57-58, pi. 6, fig. 6. [Imprint

1909.] 

1910. Phacoides (Miltha) sanctaecrucis Arnold. Arnold and

Anderson, U.S. Geol. Survey Bull. 398, pi. 28, fig. 6. 

1932. Phacoides (Miltha) sanctaecrucis Arnold. Loel and

Corey, California Univ. Pubs., Dept. Geol. Sci. Bull.,

v. 22, no. 3, p. 211, pi. 36, fig. 5.
SYSTEMATIC DESCRIPTIONS 29

1947. Miltha sanctaecrucis (Arnold). Stewart, U.S. Geol. 

Survey Prof. Paper 205-C, pi. 17, fig. 8. [Imprint 

1946.]

Type. USNM. 165569.

Type locality. USGS 4861. In "reef beds," ^ 

mile south and southeast of Barton's cabin, in the 

NWi/4 sec. 23, T. 25 S., R. 18 E., Devils Den district, 

Kern County, Calif. "Vaqueros" [Temblor] Formation, middle Miocene.

This large, very slightly inflated lucinid is characterized by very fine, somewhat irregular concentric sculpture. A network of extremely fine, 

irregular, radial riblets is evident on a few wellpreserved specimens (pi. 3, fig. 10). This species is 

very similar to the present-day Miltha xantusi 

(Dall) from the Cape San Lucas area at the tip of 

Baja California, Mexico. It is generally distinguished from the living species by its relatively 

longer shell: M. xantusi tends to be somewhat 

higher than long. The specimens at hand from the 

Wygal Sandstone Member of the Temblor Formation also seem to have a somewhat longer posterior 

dorsal slope.

Although the figured specimens are uniformly 

less inflated than Arnold's (1909) holotype (USNM 

165569), a suite of 10 specimens from USGS locality 

M3578 includes two individuals that are at least as 

inflated as the type; the degree of inflation seems 

to be a variable morphologic character.

The occurrence of Miltha in the basal sandstone 

of the type Temblor Formation marks the lowest 

stratigraphic occurrence of the genus in the California Tertiary. The genus ranges through the Miocene into the early Pliocene of the San Joaquin 

basin and the Ventura basin (Grant and Gale, 

1931). It is recognized in paleoclimatic analyses as 

a warm-water indicator because it occurs in the 

tropical Panamic molluscan province (Durham, 

1950; Addicott and Vedder, 1963).

Localities. USGS 5149, 9432, M3280, M3578, 

M3579, M3772, M3979, M4466, M4468, M4469.

Family UNGULINIDAE 

Genus FELANIELLA Dall, 1899

Felaniella harfordi (Anderson)

Plate 4, figures 2, 7

1905. Diplodonta harfordi Anderson, California Acad. Sci.

Proc., 3d ser., v. 2, no. 2, p. 197, pi. 17, figs. 88, 89.

71910. Diplodonta harfordi Anderson. Arnold, U.S. Geol.

U.S. Geol. Survey Bull. 398, pi. 39, fig. 6. [Imprint

1909.]

71910. Diplodonta harfordi Anderson. Arnold and Anderson,

U.S. Geol. Survey Bull. 396, pi. 39, fig. 6. 

1932. Diplodonta harfordi Anderson. Loel and Corey, California Univ. Pubs., Dept. Geol. Sci. Bull., v. 22, 

no. 3, p. 212, pi. 36, figs, lla, lib.

Types. GAS 62, 63 (syntypes).

Type locality. Three miles west of Coalinga, 

Fresno County, Calif. Coalinga Beds of Anderson 

(1905) [Temblor Formation], middle Miocene.

The valves of Felaniella harfordi from the basal 

sandstone member of the type Temblor Formation 

are somewhat variable in outline and are only 

slightly inflated. Generally, they are subquadrangular and have a distinctly flattened segment posteriorly (pi. 4, fig. 2). Although the interior of these 

specimens is unknown, assignment to Felaniella is 

indicated by the characteristic inequilateral profile 

of the valves and the prominent beaks.

The stratigraphic range of this species in the San 

Joaquin basin is from the upper Oligocene to the 

Pliocene. Prior to recent records from the Etchegoin Formation (Adegoke, 1969), this species has 

been recognized from only one locality of Pliocene 

age (Arnold, 1909, pi. 17, fig. 6), a record that had 

been considered doubtful by Grant and Gale (1931, 

p. 294).

Localities. USGS M3280, M3772, M4466, M4472.

Family MACTRIDAE 

Genus PSEUDOCARDIUM Gabb, 1866

Pseudocardium? sp. 

Plate 5, figure 5

An internal mold of a moderately large, inequilateral pelecypod from USGS locality M4466 near 

Zemorra Creek is doubtful identified as Pseudocardium on the basis of strongly inflated valves and 

deeply sunken muscle scars. 

Locality. USGS M4466.

Genus SPISULA Gray, 1837 

Spisula cf. S. albaria (Conrad)

Plate 4, figures 3, 4, 8

Several small, poorly preserved specimens (30 to 

50 mm long) resemble the Miocene and Pliocene 

species Spisula albaria (Conrad) more closely than 

any of the species described from the Oligocene of 

the Pacific coast. Although somewhat variable in 

outline, the valves have a trigonal outline and medially to slightly anteriorly situated beaks. They are 

relatively much higher than the elongate trigonal 

late Oligocene species S. ramonensis attenuata 

Clark (1918, p. 158-159, pi. 9, fig. 6) and S. pittsburgensis frustra Tegland (1933, p. 121, pi. 9, figs. 

9-12). Moreover, the posterior dorsal slope is relatively longer and less convex than on S. ramonensis 

attenuata. A figure of a specimen of S. albaria 

(Conrad) from the middle Miocene Astoria Formation of coastal Oregon is included for comparison 

(pi. 4, fig. 6).

Localities. USGS 5149, M3578, M3636, M3978,

493-696 O - 73 - 5
30 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

M3979, M4466?, M4468, M4469, M4470, M4471, 

M4472.

Spisula n. sp.? 

Plate 4, figure 1

1932. Spisula aff. hemphilli (Dall) n. sp.? Loel and Corey, 

California Univ. Pubs., Dept. Geol. Sci. Bull., v. 22, 

no. 3, p. 232, pi. 45, fig. 3.

Figured specimen. UCMP 31791.

Locality. UCMP A562. Pelecypod bed at about 

the 500-foot contour on the north wall of large eastwest bend of Malibu Canyon north of dam. Western 

Los Angeles County, Calif. Vaqueros Formation, 

early Miocene.

A large, inflated Spisula represented by single 

specimens from three localities is identical to the 

poorly known taxon from the Vaqueros Formation 

in the central Santa Monica Mountains. As recognized by Loel and Corey (1932, p. 232), this Spisula 

seems to be uniquely different from any of the 

described middle Tertiary species from the Pacific 

coast.

Localities. USGS M3579, M3772, M3979.

Spisula ramonensis Packard

Plate 4, figure 5

1916. Spisula albaria (Conrad) var. ramonensis Packard, 

California Univ. Pubs., Dept. Geology Bull., v. 9, 

no. 15, p. 291-292, pi. 23, fig. 5, pi. 25, figs. 1, 2. 

1918. Spisula ramonensis Packard. Clark, California Univ. 

Pubs., Dept. Geology Bull., v. 11, no. 2, p. 158, pi. 9, 

figs. 4, 5.

Type. UCMP 11118.

Type locality. UCMP 1687. One and one-half 

mile south of Walnut Creek in valley leading from 

San Ramon Valley to Tice Valley. On bank of Walnut Creek, % mile west of the point where it turns 

and flows west. Contra Costa County, Calif. Altitude 

225 feet. San Ramon Sandstone, early Miocene (?).

A few specimens from USGS locality M3280 have 

the long, nearly straight anterior dorsal slope and 

posteriorly located beaks characteristic of this 

species. Spisula ramonensis occurs in several formations of Oligocene age in California (Wagner and 

Schilling, 1923; Alien, 1945; Primmer, 1964; DeLise, 

1967) and has been recorded from the lower Miocene part of the Poul Creek Formation in the Gulf 

of Alaska Tertiary province (Clark, 1932).

Localities. USGS M3280, M4468 cf.

Spisula cf. S. rushi Wagner and Schilling 

Plate 4, figure 14

A few large Spisula from localities in the Wygal 

Sandstone Member of the Temblor Formation are 

similar to a species from the Oligocene formations 

exposed in the foothills of the San Emigdio Mountains, S. rushi Wagner and Schilling (1923, p. 256, 

pi. 47, fig. 2). These specimens are much larger than 

S. rushi. They are distinguished from Spisula n. sp., 

with which one specimen occurs in the collection 

from USGS locality M3979, by the subquadrate outline of the valves and by the anterior location of 

the beaks.

A similar species from the San Ramon Sandstone 

of the San Francisco Bay area to the north, Spisula 

occidentalis (Gabb) (Stewart, 1930, pi. 15, fig. 5), 

has a more oblique umbonal angle and has a prominent sulcus extending from near the beaks to the 

posterior dorsal extremity.

Spisula rushi ranges from the middle Oligocene 

into the late Oligocene in southern part of the San 

Joaquin basin. It occurs with the Refugian Stage 

(Schenck and Kleinpell, 1936) index fossil Acila 

sfiumardi in the upper part of the San Emigdio and 

the lower part of the Pleito Formations of Wagner 

and Schilling (1923) at the southern margin of the 

San Joaquin basin (Wagner and Schilling, 1923; 

DeLise, 1967).

Localities. -USGS M3280, M3636, M3978, M3979, 

M4470, M4471, M4472?.

Family SOLEN1DAE 

Genus SOLEN Linne, 1758

Solen aff. S. gravid us Clark 

Plate 4, figure 9

Fragments of a large Solen from USGS localities 

M3280 and M3578 are similar to S. gravidus Clark 

(1918, p. 156-157, pi. 10, fig. 7) from the San 

Ramon Formation of the Mount Diablo area, Contra 

Costa County, Calif. The anterior margin is gently 

rounded and is bordered by a weak, shallow sulcus 

that extends from near the beaks to the anterior 

ventral margin. The strength of the sulcus is variable in the few specimens available for study. The 

height of the valves is proportionately greater than 

that of the holotype of S. gravidus (UCMP 11133). 

There are additional fragments of a large Solen in 

the collections from USGS localities M3772 and 

M3979 that are specifically indeterminate but presumably represent this taxon.

Localities. USGS M3280, M3578, M4466 ?.

Family TELLINIDAE 

Genus TELLINA Linne, 1758

Subgenus OLCESIA Addicott, n. subgen.

Type. Tellina piercei (Arnold) [== T. nevadensis 

Anderson and Martin]. Middle Miocene, California.

Shell large and heavy. Posterior side longer than 

anterior side. Posterior portion of valves flexed to 

the right, flexing much stronger in right valve. Surface sculptured by fine concentric lines of growth
SYSTEMATIC DESCRIPTIONS 31

and very faint radial striae. Anterior dorsal margin 

broadly convex, posterior margin long and relatively 

straight. Hinge plate broad and very heavy. Right 

valve has a long anterior lateral, a weak anterior 

cardinal, a heavy, bifid main cardinal, and a weak 

posterior lateral. Left valve has a weak anterior 

lateral, a simple cardinal, a weak posterior cardinal, 

and a strong, slightly curved posterior lateral terminating near the base of the hinge plate. Left valve 

flattened in dorsal aspect, has slight convexity; anterior part of right valve convex, posterior part 

concave. Right valve has an elongate, weak lunule,. 

Pallial line deeply impressed, extending to base of 

the anterior muscle scar. Pallial sinus deep, has 

slight convexity dorsally, extending anteriorly to 

a prominent internal rib bordering the anterior 

muscle scar. Anterior muscle scar elongate, tear 

shaped; posterior scar subquadrate. Ligament 

elongate, sunken, base deeply set on hinge plate.

Olcesia seems to be most similar to the European 

Oligocene to Holocene genus Peronaea Poli (Afshar, 

1969, p. 30-31, pi. 5, figs. 6-10). The valves are of 

very similar shape and sculpture, but there are 

significant differences internally. The hinge of 

Olcesia is relatively much heavier, particularly anterior to the beaks, the pallial sinus is also lower 

and does not form a prominent peak, and the anterior margin of the posterior muscle scar is straight 

rather than highly contorted.

The shape of the valves and external sculpture 

also resemble the Eocene to Holocene northern Pacific subgenus Peronidia Dall (1900), but the deeply 

sunken ligamental groove, heavy hinge plate, and 

strong dentition of Olcesia are strikingly different.

Olcesia ranges from the upper Oligocene to the 

upper Miocene in California. It is named for the 

Olcese land holdings near the type locality of Tellina 

nevadensis. The name has also been applied to the 

middle Miocene Olcese Sand from which this species 

was described.

Tellina (Olcesia) piercei (Arnold)

Plate 4, figures 10, 12; plate 5, figures 12, 13

1910. Macoma piercei Arnold, U.S. Geol. Survey Bull. 396, 

p. 55-56, pi. 7, fig. 6. [Imprint 1909.]

1910. Macoma piercei Arnold. Arnold and Anderson, U.S. 

Geol. Survey Bull. 398, pi. 7, fig. 6.

1914. Tellina nevadensis Anderson and Martin, California 

Acad. Sci. Proc., 4th ser., v. 4, no. 3, p. 61-62, pi. 

2, figs. 3a-3c.

1929. Tellina nevadensis Anderson and Martin. Clark, Stratigraphy and faunal horizons of the Coast Ranges of 

California, pi. 24, fig. 3.

1932. Tellina ocoyana Conrad. Loel and Corey, California 

Univ. Pubs., Dept. Geol. Sci. Bull., v. 22, no. 3, p. 

148 (in part), pi. 43, fig. 4.

1932. Macoma nasuta (Conrad). Loel and Corey, California 

Univ. Pubs., Dept. Geol. Sci. Bull., v. 22, no. 3, p. 

228 (in part), pi. 43, fig. 7 (not fig. 8).

1965. Tellina nevadensis Anderson and Martin. Addicott, 

U.S. Geol. Survey Prof. Paper 525-C, fig. 4e.

Type. USNM 165595.

Type locality. USGS 4631, Turritella bed on 

east flank of high hill northeast of Oil City, in 

SE^NE14 sec. 16, T. 19 S., R. 15 E. Vaqueros 

[Temblor] Formation, middle Miocene.

This species has been generally identified as 

Tellina nevadensis Anderson and Martin (1914) 

from the middle Miocene Olcese Sand of the Kern 

River area on the southeast margin of the San 

Joaquin basin. Arnold's (1909, pi. 7, fig. 6) T. 

piercei has remained a poorly known taxon because 

the holotype is incomplete and poorly preserved. 

Moreover, it was originally compared with the 

Holocene species Macoma secta. The holotype, a left 

valve, clearly is not allied to M. secta. It lacks the 

convex posterior dorsal margin characteristic of 

that species and has an extremely long, deeply set 

ligamental groove. Although the hinge is not exposed 

on the holotype, there can be little doubt that it is 

idenical to T. nevadensis owing to the long, deeply 

excavated ligamental groove, the strong ridge below 

the posterior dorsal margin, the anteriorly located 

beak, and the surface sculpture of fine concentric 

ribs. The types of both species are from stratigraphic units referable to the "Temblor Stage."

Only four specimens of Tellina piercei from the 

Wygal Sandstone Member of the Temblor Formation are available for study. They are identical in 

all respects to well-preserved specimens from the 

upper part of the middle Miocene Olcese Sand from 

the Kern River area on the east side of the San 

Joaquin Valley (pi. 5, figs. 12, 13).

This large, thick-shelled species is characterized 

by a very heavy hinge plate that has well-developed 

lateral teeth. The valves are boat shaped and are 

pointed posteriorly. On the left valve, the sharp 

posterior dorsal margin is bordered by a weak 

ridge, below which is a narrow sulcus; on the right 

valve, it is bordered by a much stronger sulcus 

below which occurs a prominent ridge that extends 

to the posterior extremity.

Tellina piercei [as T. nevadensis^ has been confused with a poorly known middle Miocene species 

from the Kern River area, T. ocoyana Conrad 

(1857d, pi. 8, figs. 75, 75a). The identity of Conrad's species may never be satisfactorily determined 

because the type has apparently been lost (Keen 

and Bentson, 1944, p. 115) and the original figures 

appear to be somewhat stylized line drawings that
32 MOLLUSC AN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION. CALIF.

do not indicate the critical details of internal 

morphology. Conrad's description (1855, p. 19) and 

illustrations are of a more trigonal shell that has 

a pointed, rather than broadly rounded anterior 

extremity, and the hinge of T. ocoyana does not 

seem nearly so broad and heavy as that of T. piercei. 

Most subsequent records of T. ocoyana are presumed to be of T. piercei.

This species ranges from the upper Oligocene to 

the middle Miocene in the San Joaquin basin. It has 

not previously been recorded from strata of Oligocene age. A record of Tellina nevadensis from the 

upper Miocene Santa Margarita Formation near 

Coalinga, Calif. (Adegoke, 1969, p. 131), is not of 

this species. It is based on an internal mold (UCMP 

36765) that is much more acute posteriorly than 

T. piercei and that can only doubtfully be identified 

as a tellinid.

Localities. USGS 9432, M3578, M3978, M4471?.

Subgenus OUDARDIA Monterosato, 1884

Tellina (Oudardia) emacerata Conrad

Plate 4, figure 11

1848. Tellina oregonensis Conrad, Am. Jour. Sci., 2d ser., 

v. 5, p. 432, fig. 5 [nomen dubium, Moore, 1963, 

p. 79].

1849. Tellina emacerata Conrad, U.S. Explor. Exped.,

Geology, v. 10, app. p. 725, atlas pi. 18, fig. 4. 

1909. Tellina clallamensis Reagan, Kansas Acad. Sci. Trans.,

v. 22, p. 186-187, pi. 2, fig. 18. 

1918. Tellina oregonensis Conrad. Clark, California Univ.

Pubs., Dept. Geology Bull., v. 11, no. 2, p. 152-153,

pi. 13, fig. 1, 4. 

1923. Tellina bodegensis Hinds n. subsp.? Clark and Arnold,

California Univ. Pubs., Dept. Geol. Sci. Bull., v. 14,

no. 5, p. 149, pi. 22, figs. 7 and ?8. 

1931. Tellina (Peronidia) oregonensis Conrad. Etherington,

California Univ. Pubs., Dept. Geol. Sci. Bull., v.

20, no. 5, p. 83-84, pi. 10, figs. 6, 7. 

1942. Tellina emacerata Conrad. Weaver, Washington Univ.

[Seattle] Pubs. Geology, v. 5, p. 206, pi. 48, fig. 20,

[not pi. 48, fig. 18]. 

1964. Tellina emacerata Conrad. Moore, U.S. Geol. Survey

Prof. Paper 419, pi. 29, figs. 6, 7, 13, 14. [Imprint

1963.]

Type. USNM. 3494.

Type locality. Astoria, Oreg. Astoria Formation, 

Miocene.

This species is represented by three specimens 

from USGS locality M3578 that are identical to 

specimens of middle Miocene age from the Astoria 

Formation near Newport, Oreg. (USGS loc. M2604). 

It is characterized by a prominent ridge running 

from the beaks to the posterior extremity and a 

flattened area between this ridge and the convex 

posterior dorsal margin.

Tellina emacerata has been perhaps more commonly known as T. oregonensis Conrad (1848), a

poorly illustrated species that seems best regarded 

as a nomen dubium because the type has been lost 

(Moore, 1963, p. 79). T. emacerata is assigned to the 

subgenus Oudardia on the basis of the slanting internal rib near the anterior margin of the valves. 

This rib is only faintly discernible on the specimen 

from the Wygal Sandstone Member of the Temblor 

Formation, apparently because of poor preservation.

This is the first record of Tellina emacerata from 

strata of Oligocene age in the San Joaquin basin. 

It ranges from the late Oligocene to the late Miocene 

(Trask, 1922) in California but has a much shorter 

range in Oregon and Washington, having been reported only from strata of early and middle Miocene 

age (Durham, 1944; Moore, 1963).

Locality. USGS M3578.

Subgenus TELLINELLA Morch, 1853 

Tellina (Tellinella) tenuilineata Clark

Plate 5, figures 2, 8 

1918. Tellina tenuilineata Clark, California Univ. Pubs.,

Dept. Geology Bull., v. 11, no. 2, p. 153-154, pi. 10,

figs. 1, 3, 5. 

1929. Tellina tenuilineata Clark. Clark, Stratigraphy and

faunal horizons of the Coast Ranges of California,

pi. 16, fig. 1.

Types. Holotype, UCMP 31169; paratype, 

UCMP 11128.

Type locality. UCMP 1131, i/2 mile southwest of 

Walnut Creek, Contra Cosa County, Calif., in creek 

bed about 100 yards east of Oakland and Antioch 

bridge. Altitude 150 feet. San Ramon Sandstone, 

early Miocene (?).

Three specimens of this distinctive tellinid are 

in the collections from the lowest sandstone member 

of the Temblor Formation. They are relatively more 

elongate than Clark's type specimen from the San 

Ramon Sandstone, and one specimen (pi. 5, fig. 2) 

is much more strongly flexed posteriorly than the 

holotype. This condition is attributed to deformation because the other specimens are only very 

slightly flexed.

In addition to occurrences in the San Ramon 

Sandstone (Clark, 1918), Tellina tenuilineata has 

been reported from the San Juan Bautista Formation (Alien, 1945) and from middle Miocene localities in the Temblor Formation (Loel and Corey, 

1932).

Localities. USGS 5149, 9432, M3578, M4466?.

Subgenus? 

Tellina cf. T. townsendensis Clark

Plate 6, figure 7

Two poorly preserved specimens of an elongate 

tellinid from USGS locality M3578 seem to repre-
SYSTEMATIC DESCRIPTIONS 33

sent the Oligocene species Tellina townsendensis 

Clark (1925, p. 94, pi. 12, figs. 11, 12) from Washington. Records of this species from Washington 

(Durham, 1944; Clark, 1925) are from the lower 

part of the "Lincoln Stage": Durham's (1944) 

Molopophorus stephensoni and Molopophorus gabbi 

Zones. This taxon differs from the "Lincoln Stage" 

species Tellina aduncanasa Hickman (1969, p. 55- 

56, pi. 6, figs. 7-12) in being somewhat longer and 

in having a broadly convex posterior dorsal margin. 

Locality. USGS M3578.

Tellina? cf. T. vancouverensis Clark and Arnold 

Plate 4, figure 13

A very poorly preserved tellinid from USGS locality M3578 appears to be conspecific with Tellina 

vancouverensis Clark and Arnold (1923, p. 149-150, 

pi. 22, figs. 5, 6) from the Sooke Formation of 

southwestern Vancouver Island, British Columbia.

Locality. USGS M3578.

Genus MACOMA Leach, 1819

Macoma arctata (Conrad) 

Plate 5, figures 4, 7

1849. Tellina arctata Conrad, U.S. Explor. Exped., Geology, 

v. 10, app. p. 725, atlas pi. 18, figs. 3, 3a.

1909. Tellina arctata Conrad. Reagan, Kansas Acad. Sci. 

Trans., v. 22, p. 184, 186, pi. 2, figs. 16, 16a.

1909. Tellina arctata Conrad var. juana Reagan, Kansas 

Acad. Sci. Trans., v. 22, p. 186, pi. 1, fig. 17.

1912. Macoma wynootcheensis Weaver [in part], Washington Geol. Survey Bull. 15, p. 66, pi. 15, fig. 130 [not 

figs. 128, 129].

1929. Macoma arctata (Conrad). Clark, Stratigraphy and 

faunal horizons of the Coast Ranges of California, 

pi. 22, figs. 4, 6.

1931. Macoma (Psammacoma) arctata (Conrad). Etherington, California Univ. Pubs., Dept. Geol. Sci. Bull., 

v. 20, no. 5, p. 84-85, pi. 10.

71932. Macoma arctata (Conrad). Loel and Corey, California Univ. Pubs., Dept. Geol. Sci: Bull., v. 22, no. 

3, p. 227 (in part), pi. 43, fig. 2 [not fig. 1].

1942. Macoma arctata (Conrad). Weaver, Washington 

Univ. [Seattle] Pubs. Geology, v. 5, p. 208-209, pi. 

49, figs. 3, 5, 12, pi. 59, fig. 15.

1942. Macoma arctata (Conrad) var. wynoocheensis 

Weaver. Weaver, Washington Univ. [Seattle] 

Pubs. Geology, v. 5, p. 209, pi. 49, fig. 8.

1958. Macoma arctata (Conrad). Hall, California Univ. 

Pubs., Dept. Geol. Sci. Bull., v. 34, no. 1, p. 55, 

pi. 8, fig. 4.

1964. Macoma arctata (Conrad). Moore, U.S. Geol. Survey 

Prof. Paper 419, p. 81, pi. 28, figs. 6, 7, 10, 11, 13, 

pi. 29, fig. 8. [Imprint 1964.]

1972. Macoma arctata (Conrad). Addicott, Soc. Econ. 

Paleontologists and Mineralogists, Pacific Sec., 

Bakersfield, Calif., 1972, Proc., pi. 1, fig. 14.

Type. USNM 3489.

Type locality. Astoria, Oreg. Astoria Formation, 

Miocene.

This species is characterized by moderately large, 

elongated valves that have posteriorly situated beaks 

and a fairly strong posterior flexure. It is somewhat 

similar to the living species, Macoma nasuta (Conrad), which has a higher shell and more centrally 

located beaks and which is more acute and more 

strongly flexed posteriorly.

Specimens in the Wygal Sandstone Member of 

the Temblor Formation constitute a range extension 

of this species. The lowest previously known stratigraphic occurrence in California is from the early 

Miocene "Vaqueros Stage" (Loel and Corey, 1932, 

p. 227). Macoma arctata also occurs in strata of 

early Miocene age in northwestern Oregon where it 

is found in the Nye Mudstone of the Newport embayment in association with mollusks referable to 

the upper part of the "Blakeley Stage" (USGS loc. 

M3630). This species is widespread in strata of 

middle Miocene age from southern California to the 

Gulf of Alaska where there is an unrecorded occurrence in the lower part of the Yakataga Formation 

(Saburo Kanno, written commun., July 1970). It is 

not known to occur in the late Miocene.

This is one of the few stratigraphic records of 

large species of Macoma from pre-Miocene strata 

of the Pacific coast. None is recorded from the 

Oligocene of western Washington (Tegland, 1933; 

Durham, 1944) or western Oregon (Warren and 

others, 1945; Vokes and others, 1949). There is, 

however, a middle Oligocene record from the San 

Emigdio Mountains at the southern margin of the 

San Joaquin basin in California Macoma cf. M. 

nasuta (Conrad) by Wagner and Schilling (1923, 

p. 248). This taxon, which occurs with Acila shumardi in the lower part of the Pleito Formation of 

Wagner and Schilling (1923), could conceivably 

represent M. arctata.

The holotype of Weaver's Macoma ivynootcheensis (1912, p. 66, pi. 15, fig. 130) is M. arctata. The 

other specimens from thej. type locality (Weaver, 

1912, pi. 15, figs. 128, 129), which is in the Astoria 

Formation (Gower and Pease, 1965) in the vicinity 

of Montesano, Wash., have extremely elongate valves 

and beaks that are situated unusually close to the 

posterior margin. These may represent an extremely 

variable form of M. arctata, or an entirely different 

species.

Localities. USGS 5149, M3280, M3281, M3578, 

M3579 cf., M3772, M4466, M4468, M4469, M4471 

cf., M4472?.
34 MOLLUSC AN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

Genus HETEROMACOMA Habe, 1952 

Heteromacoma rostellata (Clark)

Plate 5, figures 1, 3, 6, 9-11; 

plate 6, figures 2, 4, 14

1918. Metis rostellata Clark, California Univ. Pubs., Dept.

Geology Bull., v. 11, no. 2, p. 154-155, pi. 9, fig. 7. 

1923. Metis vancouverensis Clark and Arnold, California

Univ. Pubs., Dept. Geol. Sci. Bull., v. 14, no. 5, p.

150, pi. 22, figs. 3, 4.

1932. Macoma sespeensis Loel and Corey, California Univ. 

Pubs., Dept. Geol. Sci. Bull., v. 22, no. 3, p. 228- 

229, pi. 43, figs. 10-12.

1933. Poromya n. sp. Tegland, California Univ. Pubs., Dept.

Geol. Sci. Bull., v. 23, no. 3, p. 92.

1942. Poromya teglandae Weaver, Washington Univ. [Seattle] Pubs. Geology v. 5, p. 121-122, pi. 25, fig. 23. 

1942. Apolymetis vancouverensis (Clark and Arnold).

Weaver, Washington Univ. [Seattle] Pubs. Geology,

v. 5, p. 221, pi. 50, fig. 17. 

1944. Apolymetis twinensis Durham, California Univ. Pubs.,

Dept. Geol. Sci. Bull., v. 27, no. 5, p. 150, pi. 13,

fig. 7. 

1951. Macoma sespeensis Loel and Corey. Lutz, California

Univ. Pubs., Dept. Geol. Sci. Bull., v. 28, no. 13,

p. 387-388, pi. 16, figs. 5, 6. 

1963. Apolymetis cf. A. sespeensis (Loel and Corey). Kleinpell and Weaver, California Univ. Pubs., Dept. Geol.

Sci. Bull., v. 43, p. 207, pi. 38, fig. 2. 

1966. Macoma (Heteromacoma) vancouverensis (Clark and

Arnold). Addicott, Jour. Paleontology, v. 40, no. 3,

p. 644-645, pi. 76, figs. 1, 4. 

1969. Macoma (Heteromacoma) vancouverensis (Clark and

Arnold). Hickman, Oregon Univ. Mus. Nat. History

Bull. 16, p. 58-59, pi. 7, figs. 3, 5, 7. 

1972. Heteromacoma rostellata (Clark). Addicott, Soc. Econ.

Paleontologists and Mineralogists, Pacific Sec.

Bakersfield, Calif., 1972, Proc., pi. 1, figs. 1, 6.

Type. UCMP 11120.

Type locality. UCMP 1131, 1/2 mile southwest of 

Walnut Creek, Contra Costa County, Calif., in creek 

bed about 100 yards east of Oakland and Antioch 

bridge. Altitude 150 feet. San Ramon Sandstone, 

early Miocene (?).

Heteromacoma rostellata is an unusually variable 

species, as suggested by the number of specific 

names included in the synonymy. A large population 

of mature individuals represented in the collection 

from USGS locality M3280 clearly demonstrates the 

range of variation in outline of the valves. The most 

common forms are of subquadrate (pi. 5, figs. 10 

and 11; pi. 6, fig. 2) and elongate shape (pi. 5, fig. 

9; pi. 6, fig. 4) ; a less common form is suborbicular 

in outline (pi. 5, figs. 1, 3, 6; pi. 6, fig. 14).

Some of the subquadrate specimens resemble the 

veneroid genus Pitar, particularly those in which 

the posterior part of the valve has been broken off. 

This form was originally described by Clark (1918, 

p. 154-155, pi. 9, fig. 7) as Metis rostellata from the

San Ramon Sandstone of Contra Costa County, 

Calif.

The elongate form was described by Loel and 

Corey (1932, p. 228-229, pi. 43, figs. 10-12) as 

Macoma sespeensis from the Vaqueros Formation 

of coastal California.

The suborbicular form that was named Metis 

vancouverensis by Clark and Arnold (1923, p. 150, 

pi. 22, figs. 3, 4) was based on specimens from the 

lower Miocene ( ?) Sooke Formation of southwestern 

Vancouver Island, British Columbia. An extreme 

variant of this form, almost suborbicular in outline, 

from the upper member of the Twin River Formation of western Washington (Addicott, 1966), was 

named Poromya teglandae by Weaver (1942, p. 

121-122, pi. 25, fig. 23).

Variation in this taxon was first recognized by 

Kleinpell and Weaver (1963, p. 207), who suggested 

that Poromya teglandae, Macoma sespeensis, and 

Apolymetis twinensis were synonyms. Subsequently, 

Addicott (1966) and Hickman (1969) extended this 

treatment to include the suborbicular species Metis 

vancouverensis Clark and Arnold in this taxon. The 

present concept of this species further includes 

Metis rostellata Clark.

Primmer (1965) first assigned Macoma sespeensis and Metis rostellata to Heteromacoma, a very 

shallow-water genus that is living off Japan and 

Korea (Kira, 1962, p. 172), and included these two 

species in a new subgenus, which he differentiated 

from Heteromacoma s. s. principally because of a 

somewhat shorter ligament and related hinge structure. In recognizing these as distinct species, he 

contrasted the elongate shape of H. sespeensis with 

the subquadrate shape of H. rostellata and further 

indicated minor differences in ligamental width and 

surface of the nymph plate. However, specimens 

from the middle Oligocene, lower part of the Pleito 

Formation of Wagner and Schilling (1923, their loc. 

3179) of the San Emigdio Mountains seemed to 

indicate that these differences were not constant 

and that the two taxa might intergrade (Primmer, 

1965, p. 137).

The genus Heteromacoma is characterized by a 

prominent sulcus extending from near the beaks to 

the posterior ventral region of the valves where it 

is reflected by a shallow indentation in the margin, 

an immersed ligament set on a deeply sunken ligamental groove, and a pseudolunule (Keen, 1962). 

Along the Pacific coast of North America the genus 

ranges from the middle Oligocene "Lincoln Stage" 

or Refugian Stage to the middle Miocene "Temblor 

Stage." Its geographic distribution during the 

Oligocene and the early Miocene extended from
SYSTEMATIC DESCRIPTIONS 35

southern California (Kleinpell and Weaver, 1963; 

Loel and Corey, 1932) to southwestern British Columbia (Clark and Arnold, 1923). The highest 

stratigraphic occurrence, in strata of middle Miocene age, is in northern California where it occurs 

in the Sobrante Sandstone of the San Francisco 

Bay area (Lutz, 1951).

Localities. USGS 5149, M3280, M3281, M3578, 

M3772, M3978, M3979, M3984, M4466, M4468, 

M4469, M4470, M4471, M4472, M4473.

Family VENERIDAE 

Genus AMIANTIS Carpenter, 1864

Amiantis mathewsoni (Gabb)

Plate 7, figures 1, 4, 8, 13, 14 

1866. Chione mathewsonii Gabb, California Geol. Survey,

Paleontology, v. 2, sec. 1, pt. 1, p. 23, pi. 5, fig. 39. 

1918. Antigona (Artena) mathewsonii (Gabb). Clark, California Univ. Pubs., Dept. Geology Bull., v. 11, no.

2, p. 143-144, pi. 15, figs. 5-7. 

71918. Antigona (Artena) neglecta Clark, California Univ.

Pubs., Dept. Geology Bull., v. 11, no. 2, p. 144,

pi. 8, figs. 3, 4, 6. 

71918. Antigona (Ventricola) undosa Clark, California

Univ. Pubs., Dept. Geology Bull., v. 11, no. 2, p.

145, pi. 8, figs. 1, 2, 5. 

1930. Amiantisl mathewsonii (Gabb). Stewart, Acad. Nat.

Sci. Philadelphia Spec. Pub. 3, p. 245-246, pi. 14,

fig. 2. 

1963. AmiantisC!) mathewsonii (Gabb). Kleinpell and

Weaver, California Univ. Pubs. Geol. Sci., v. 43,

p. 204, pi. 35, figs. 8, 9.

Lectotype. ANSP 4532 (designated by Stewart, 

1930).

Type locality. Miocene (?) Martinez, Calif. Presumably from the San Ramon Sandstone.

This species occurs abundantly in most of the collections from the Wygal Sandstone Member of the 

Temblor Formation. Well-preserved specimens are 

characterized by coarse, somewhat irregular concentric lamellae between which are very fine concentric threads. The coarse lamellae are sharp edged 

and closely spaced anteriorly, posteriorly, and ventrally. In the middle part of the valve, these lamallae 

terminate in a sharp edge that is reflected dorsally. 

There is a well-developed escutcheon that is bordered, on the left valve, by a strong cord. The pallial 

sinus is deep, and the apex reaches the anterior half 

of the valve.

Assignment to Amiantis has been questioned by 

some previous workers (Stewart, 1930, 1946; Kleinpell and Weaver, 1963), possibly because the nature 

of the pallial sinus and the dentition of the right 

valve were not known. The pallial sinus is similar 

to that of the type of Amiantis, A. callosa (Conrad) 

but differs in having a less sharply pointed apex. 

There are anterior lateral teeth in both valves; the

right anterior lateral, however, is rather weak. The 

right anterior cardinal and the middle cardinal are 

sharply bifid (pi. 7, fig. 13), differing from A. 

callosa.

A wide range of variation in the shape of the 

valves is exhibited by the specimens at hand. Most 

are subtrigonal to subquadrate depending on the 

convexity of the posterior dorsal slope. Specimens 

of Amiantis from USGS locality M3578 are especially variable. They can be segregated into two taxa, 

one of which is relatively much more elongated 

posteriorly than A. mathewsoni (pi. 7, figs. 6, 7) 

and may represent a new species.

The range of variation in shape and sculpture 

within individual collections seems sufficiently broad 

to regard dark's (1918) species Antigona neglecta 

and A. undosa as probable synonyms of A. mathewsoni with which they occur in the San Ramon Sandstone of Contra Costa County, Calif., the probable 

formation from which the latter species was described by Gabb (1866).

Records of this species from the middle Miocene 

"Temblor Stage" (Schenck and Keen, 1940; Stewart, 1946; Adegoke, 1969) are doubtful. Schenck 

and Keen's record from the Olcese Sand of the eastern margin of the San Joaquin basin are based on 

a relatively smooth, subquadrate taxon whose dentition is entirely different from Amiantis mathewsoni. 

The middle Miocene taxon (pi. 7, figs. 2, 3, 11) has 

a much narrower hinge plate and a broad, rather 

than bladelike middle cardinal in the right valve, 

and the right posterior cardinal is not sharply bifid 

as on A. mathewsoni. The specimens from the Olcese 

Sand are similar to A. diabloensis (Anderson, 1905) 

but seem to represent an undescribed species because of the much heavier middle and posterior 

cardinal teeth in the left valve and the more elongate, less tumid valves.

A doubtful record from the Temblor Formation 

on Reef Ridge, Fresno County, Calif. (Stewart, 

1946, USGS loc. 14402), is of a relatively smooth, 

quadrate specimen whose partially exposed hinge 

plate is much narrower anteriorly than on A. 

mathewsoni. Adegoke's (1969) unfigured hypotype 

from the Temblor Formation at Reef Ridge (UCMP 

32532) is a poorly preserved specimen that is 

generically indeterminate.

Amiantis mathewsoni ranges from the middle 

Oligocene to the late Oligoceine or early Miocene. 

Its lowest stratigraphic occurrences are in the middle part of the Gaviota Formation of Kleinpell and 

Weaver (1963) and the upper part of the San 

Emigdio Formation of Wagner and Schilling 

(1923). The highest occurrence is in the San
36 MOLLUSC AN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

Ramon Sandstone of Clark (1918), which may be 

as young as early Miocene in the sense of the Pacific megafaunal chronology of Weaver and others 

(1944). There are no authenticated records, however, in the lower Miocene Vaqueros Formation of 

Loel and Corey (1932).

Localities. USGS 5149, M3280, M3578, M3579, 

M3772, M3972, M3978, M3979, M3984 cf., M4466?, 

M4468 cf., M4469 cf.

Amiantis n. sp.? 

Plate 6, figure 6; plate 7, figures 6, 7

Several poorly preserved specimens in the collection from USGS locality M3578 have exceptionally elongate valves and a relatively long posterior 

dorsal slope. Although the valves appear to be somewhat decorticated and are clearly thinner than on 

A. mathewsoni, the sculptural pattern is similar as 

are details of the escutcheon, lunule, and pallial 

sinus. There are several other specimens in this 

collection that are clearly referable to A. mathewsoni. They are variable in outline but do not seem 

to be intergradational with the elongate specimens 

that are here doubtfully considered to represent a 

new species. The hinge of this taxon is not known, 

but the pallial sinus is typical of Amiantis; it is deep 

and consists of a linear dorsal limb and slightly 

concave ventral limb (pi. 7, fig. 6). The apex, as in 

A. mathewsoni, is not sharply pointed.

Localities. USGS M3578, M3772?, M4466.

Genus CLEMENTIA Gray, 1842 

Subgenus EGESTA Conrad, 1845

dementia (Egesta) pertenuis (Gabb)

Plate 7, figures 9, 12; plate 8, figures 1, 3, 19

1866. Venus kennerlyi Reeve?. Gabb, California Geol. Survey, Paleontology, v. 2, sec. 1, pt. 1, p. 22, pi. 5, 

fig. 37.

1869. Venus pertenuis Gabb, California Geol. Survey, Paleontology, v. 2, sec. 1, pt. 2, p. 55-56, pi. 5, fig. 37.

1910. Venus pertenuis Gabb. Arnold, U.S. Geol. Survey Bull. 

396, pi. 8, fig. 3. [Imprint 1909.]

1910. Venus pertenuis Gabb. Arnold and Anderson, U.S. 

Geol. Survey Bull. 398, pi. 30, fig. 3.

1926. dementia (Egesta) pertenuis (Gabb). Woodring, U.S. 

Geol. Survey Prof. Paper 147-C, p. 40-42, pi. 16, 

figs. 1-6.

1940. dementia pertenuis (Gabb). Schenck and Keen, California fossils for the field geologist, pi. 34, figs. 1, 2.

1958. dementia pertenuis (Gabb). Hall, California Univ. 

Pubs. Geol. Sci. Bull., v. 34, no. 1, p. 54, pi. 3, fig. 2.

Type. UCMP 12000.

Type locality. At Griswold's [Ranch] on road to 

New Idria, San Benito County, Calif. Temblor Formation, Miocene.

Specimens of dementia pertenuis from the Wygal 

Sandstone Member are subquadrate to subtrigonal

in outline. They are sculptured by broad concentric 

folds on the dorsal part of the valves that grade, 

ventrally, into fine, irregular lines of growth.

This is the initial record of the genus dementia 

from strata of Oligocene age along the Pacific coast 

of North America. The lowest previously recorded 

stratigraphic occurrence in this region is from 

strata assigned to the provincial lower Miocene 

(Woodring, 1926; Cushman and LeRoy, 1938). A 

late Oligocene occurrence from the Pacific coast of 

South America has been noted, however, by Woodring (1926, p. 31).

Localities. USGS 5149, 9432, M3280, M3578, 

M3579, M3772, M3978, M4466, M4468, M4469.

Genus DOS1N1A Scopoli, 1777 

Subgenus DOSINIA s. s.

Dosinia (Dosinia) whitneyi (Gabb)

Plate 6, figures 1, 3, 9, 12, 13; 

plate 7, figures 5, 10

1866. Chione whitneyi Gabb, California Geol. Survey, Paleontology, v. 2, sec. 1, pt. 1, p. 23-24, pi. 5, fig. 40.

1866. Dosinia mathewsonii Gabb, California Geol. Survey, 

Paleontology, v. 2, p. 57, pi. 15, fig. 16.

1918. Dosinia (Dosinidia) matheivsoni Gabb. Clark, California Univ. Pubs., Dept. Geology Bull., v. 11, no. 

2, p. 141-142, pi. 7, figs. 1, 2, 5, 6, 9.

1918. Dosinia (Dosinidia) whitneyi (Gabb). Clark, California Univ. Pubs., Dept. Geology Bull., v. 11, no. 

2, p. 143, pi. 7, figs. 3, 4.

1930. Dosinia mathewsonii Gabb. Stewart, Acad. Nat. Sci. 

Spec. Pub. 3, p. 230-232, pi. 14, fig. 7.

1951. Dosinia (Dosinidia) whitneyi (Gabb). Lutz, California 

Univ. Pubs., Dept. Geol. Sci. Bull., v. 28, no. 13, 

p. 389-390, pi. 16, figs. 1, 2.

1959. Dosinia (Dosinidia) mathewsonii Gabb. Durham, Veliger, v. 2, no. 2, pi. 4, figs. 2, 3.

1964. Dosinia (Dosinia) whitneyi (Gabb). Moore, U.S. Geol. 

Survey Prof. Paper 419, p. 73-74, pi. 24, figs. 1-10. 

[Imprint 1963.]

1972. Dosinia whitneyi (Gabb). Addicott, Soc. Econ. Paleontologists and Mineralogists, Pacific Sec., Bakersfield, 

Calif., 1972, Proc., pi. 1, fig. 4.

Tijpe. UCMP 11999.

Type locality. Near Martintez Creek, Contra 

Costa County, California. San Ramon Sandstone, 

early Miocene (?).

Types of Dosinia mathewsonii Gabb. ANSP 

4485 (syntypes).

Type locality. Probably from the San Ramon 

Sandstone near Walnut Creek, Contra Costa 

County, Calif. (Stewart, 1930, p. 231).

Discrimination of Dosinia matheivsoni Gabb 

(1866), also from the San Ramon Sandstone, from 

D. ivhitneyi principally on the basis of a more angular dorsal margin (Clark, 1918; Adegoke, 1969) 

seems to have been made on comparison of differently oriented figures. Moore's (1963) illustrations
SYSTEMATIC DESCRIPTIONS 37

of the type of D. whitneyi and of one of Clark's 

(1918) specimens of D. mathewsoni indicate that 

one, rather than two, species is represented.

Dosinia whitneyi is represented by poorly preserved specimens from the so-called Phacoides Sand. 

These vary somewhat in the degree of inflation of 

the valves and in the angularity of the dorsal margin. The exterior is well preserved only on a few 

of the smaller specimens (pi. 7, fig. 5).

This species ranges from the upper Oligocene to 

the middle Miocene in California. During the middle 

Miocene, it ranged as far north as northwestern 

Washington (Arnold and Hannibal, 1913).

Localities. USGS 9432, M3280, M3578, M3772, 

M3979, M4466, M4468?, M4469 cf., M4470?, M4471, 

M4472.

Genus PITAR Romer, 1857

Pitar sp.

Plate 6, figure 10

An internal mold from USGS locality M3978 may 

represent Pitar. It is very strongly inflated and has 

a subquadrate outline that is more nearly equidimensional than P. (Katherinella) cf. P. (K.) californica. It might represent P. lorenzana (Clark, 

1918, p. 147-148, pi. 10, figs. 2, 4), a comparably 

large species from the San Ramon Sandstone, but 

it appears to have a much less convex posterior 

dorsal slope and to be more produced anteriorly.

Locality. USGS M3978.

Submenus KATHERINELLA Tegland, 1929

Pitar (Katherinella) cf. P. (K.) californica (Clark) 

Plate 6, figures 8, 11

Several poorly preserved specimens from localities in the Wygal Sandstone Member are similar to 

Pitar californica (Clark, 1918, pi. 11, figs. 2, 3, 4, 

11) from the San Ramon Sandstone of Contra Costa 

County, Calif. The figured specimens differ, however, in being relatively more produced anteriorly. 

Both specimens are more elongate than any species 

described from the middle Tertiary of the Pacific 

Coast States.

Assignment of this species to Katherinella is suggested by the pouting lunule that is set off by an 

incised line (Clark, 1918, p. 148), a feature similar 

to that on specimens of Pitar (Katherinella} angustifrons (Conrad) from the Astoria Formation of 

coastal Oregon (USGS loc. M2116). A similar, 

faintly incised line occurs on one of the specimens 

from USGS locality M3280.

Localities. USGS 5149?, M3280, M3772?, M4466, 

M4472.

Genus SECURELLA Parker, 1949

Securella cf. S. cryptolineata (Clark)

Plate 6, figure 5

A poorly preserved specimen of Securella in the 

collection from USGS locality M3280 resembles, 

very closely, some of the topotypes of S. cryptolineata (Clark) described and figured by Parker 

(1949, p. 589-590, pi. 94, figs. 10, 11, 13) from the 

San Ramon Formation of the Mount Diablo area, 

California. The specimen is heavy shelled and has 

a relatively broad hinge plate. Although the surface 

is deeply eroded and the consequent pattern of 

widely spaced ribs does not appear to be that of 

Securella, there is a small area near the anterior 

margin of the shell on which the original surface 

sculpture of closely spaced concentric lamellae characteristic of this genus is preserved.

This species has been doubtfully identified from 

the presumably correlative upper part of the Pleito 

Formation of Wagner and Schilling (1923) of the 

San Emigdio Mountains at the southern margin of 

the San Joaquin basin (Wagner and Schilling, 1923, 

p. 245-246) as Chione cf. C. lineolata Clark.

Locality. USGS M3280.

Order MYOIDA

Family MYIDAE

Genus PANOPEA Menard, 1807

Panopea ramonensis (Clark)

Plate 8, figure 20 

1925. Panope ramonensis Clark, California Univ. Pubs.,

Dept. Geol. Sci. Bull., v. 15, no. 4, p. 106, pi. 10,

figs. 2, 3. 

1929. Panope ramonensis Clark. Clark, Stratigraphy and

faunal horizons of the Coast Ranges of California,

pi. 15, figs. 5, 7. 

1942. Panope ramonensis Clark. Weaver, Washington Univ.

[Seattle] Pubs. Geology, v. 5, p. 263-264, pi. 59,

fig. 11.

1969. Panopea (Panopea) ramonensis Clark. Hickman, Oregon Univ. Mus. Nat. History Bull. 16, p. 65-66, pi.

8, figs. 8, 12.

Types. Holotype, UCMP 30330; paratype, 

UCMP 30331.

Type locality. UCMP 1131, i/2 mile southwest of 

Walnut Creek, Contra Costa County, Calif, in creek 

bed about 100 yards east of Oakland and Antioch 

bridge. Altitude 150 feet. San Ramon Sandstone, 

early Miocene (?).

An elongate Panopea from the Wygal Sandstone 

Member of the Temblor Formation differs from the 

common middle and late Cenozoic species P. abrupta 

(Conrad) by having consistently longer valves. 

Some of the specimens have medially situated beaks 

as on the holotype from the San Ramon Sandstone. 

On other specimens (pi. 8, fig. 20), the beaks are

493-696 O - 73 - 4
38 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

located anterior to the middle of the valves. Specimens from USGS locality M3280 have a faint sulcus extending- from near the beaks to the posterior 

ventral margin similar to the sulcus on the paratype of P. ramonensis (Clark, 1925, pi. 10, fig. 2).

Panopea estrellana (Conrad, 1857b, p. 194, pi. 7, 

fig. 5), a late Miocene species from the California 

Coast Ranges, is less elongate than P. ramonensis. 

Although recognized by some workers as a separate 

and distinct species (Durham, 1944; Adegoke, 

1969), it seems to be best treated as a synonym of 

P. abrupta as concluded by Moore (1963).

This species ranges from strata of middle Oligocene (Primmer, 1964) to middle Miocene (Weaver, 

1942) age on the Pacific coast. It may be represented in the Pleito Formation of Wagner and 

Schilling (1923, check list 2) of the southern margin of the San Joaquin basin by their Panope cf. 

P. estrellana.

Localities. USGS 5149, M3280, M3578, M3772, 

M3978, M4466?, M4469, cf., M4473.

Class SCAPHOPODA

Family DENTALIIDAE

Genus DENTALIUM Linne, 1758

Dentalium laneensis Hickman 

Plate 8, figure 14

1969. Dentalium (IFissidentalium) laneensis Hickman, Oregon Univ. Mus. Nat. History Bull. 16, p. 74, pi. 

9, figs. 1-6.

1972. Dentalium laneensis Hickman. Addicott, Soc. Econ. 

Paleontologists and Mineralogists Pacific Sec., 

Bakersfield, Calif., 1972, Proc., pi. 1, fig. 9.

Types. Holotype, UO 27332; paratypes, UO 

27333-27339.

Type locality. UO 2538, roadcut at 30th Ave. 

and Agate St., Eugene, Oreg. (NW*4 sec. 8, T. 18 

S., R. 3 W., Eugene 15' quad.). Eugene Formation, 

Oligocene.

Dentalium laneensis is represented by a few incomplete specimens from the Wygal Sandstone 

~lember. They are characterized by a relatively 

arge, thick shell sculptured by numerous broad 

ongitudinal ribs between which are intercalated 

iner secondary ribs. D. radiolineata Clark (1918, 

p. 191, pi. 22, fig. 12) from the early Miocene (?) 

San Ramon Sandstone of central California differs 

from D. laneensis in having fewer radial ribs that 

are narrow and crested in cross section.

This is the only record of this species from California as well as the only record from strata of late 

Oligocene age, previous records being from the 

lower and middle Oligocene Eugene Formation of 

western Oregon. The species also occurs in the 

middle Oligocene Pittsburg Bluff Formation of

western Oregon (E. J. Moore, written commun., 

Oct. 1971).

Localities. USGS M3280, M3281, M3578, M3772, 

M3978.

FOSSIL LOCALITIES

USGS localities (Washington, D.C., register)

Locality Description

4941. Three-fourths of a mile north of Miller Brothers 

ranch house beside their grade road, 6 miles east 

of Annette [south side of road between Franciscan 

Creek and Miller Flats, about 200 ft south of 

ridge crest; SW^SW^ sec. 36, T. 26 S., R. 17 E., 

Packwood Creek 7%' quad.]. Vaqueros Sandstone 

[Carneros Sandstone Member (?) of the Temblor 

Formation, about 1,000 ft stratigraphically below 

the base of the Media Shale Member.] Same as 

USGS loc. M2633. Collected by Ralph Arnold, 

1905.

5149. Three-fourths of a mile southwest of Carneros 

Spring, SW% sec. 5, T. 29 S., R. 20 E. Vaqueros 

Sandstone [Wygal Sandstone Member of the 

Temblor Formation]. Same as USGS loc. M4469. 

Collected by Ralph Arnold, 1908.

6622. North bank of Kern River, 10-11 miles northeast of 

Bakersfield. Float rock at base of bluff below 

where fossils were collected at USGS loc. 6623. 

Middle part of lower Miocene. These fossils are 

unquestionably from beds in the cliffs at whose 

foot they lie and are from the same horizon as 

those of USGS loc. 6623 [lower part of the Round 

Mountain Silt, middle Miocene]. Collected by R. 

W. Pack and J. D. Northrop, October 1911.

6627. Twelve miles N. 30° E. of Bakersfield. In center 

W% sec. 36, T. 27 S., R. 28 E. In small arroyo 

tributary to Adobe Canyon from west. About 1 

mile above its mouth. In first arroyo upstream 

from 1,070-ft hill. Middle part of lower Miocene 

[lower part of the Olcese Sand, middle Miocene]. 

Collected by R. W. Pack, Sept. 2, 1911, and A. T. 

Schwennessen, Aug. 31, 1911.

9427. Basal beds of the Vaqueros [Temblor Formation], 

on hill slope just south of Carneros Spring near 

center of sec. 5, T. 29 S., R. 20 E. Collected by 

Walter English, 1916.

9432. On east side of creek near streambed, about 125 ft 

east of bluff of Point of Rocks Sandstone. Near 

center of west line of SE 1^ sec. 18, T. 29 S., R. 

20 E. Basal Vaqueros Sandstone [Wygal Sandstone Member of the Temblor Formation]. Collected by W. S. W. Kew, 1916.

USGS Cenozoic localities (Menlo Park, Calif., register) 

M1596. Pelecypod biostrome on east side of southerly trending canyon, 1,400 ft north, 100 ft west of SE. 

cor. sec. 24, T. 28 S., R. 28 E., Oil Center quad. 

(1954 ed.). Near the top of the Olcese Sand. Same 

as UCMP loc. 1603. Collected by W. O. Addicott, 

1962.

M1599. Bottom of southeasterly trending gully 900 ft south, 

150 ft east of NW. cor. sec. 33, T. 28 S., R. 29 E., 

Rio Bravo Ranch quad. (1954 ed.). Near the top 

of the Olcese Sand, 17 ft stratigraphically below 

USGS loc. M1600. Same as UCMP loc. B1599. 

Collected by W. O. Addicott, 1962.
FOSSIL LOCALITIES 39

Locality Description

M1802. Seacliff exposure north of Marine Gardens, a locally 

named point east of Gull Rock, 350 ft south, 3,900 

ft west of NE. cor. sec. 32, T. 9 S., R. 11 W., 

Cape Foulweather 15' quad. Oregon. Astoria 

Formation. Collected by W. 0. Addicott, 1963.

M2544. Intertidal and spray zone exposure at mouth of 

Kirby Creek about 7,200 ft west of provincial 

highway 14 bridge over Muir Creek, Sooke 92 

B/5 quad. Renfrew District, Vancouver Island, 

British Columbia. Sooke Formation. Collected by 

W. 0. Addicott, 1965.

M2631. About one-fourth of a mile south of the mouth of 

Cedar Canyon on east side of road, 1,800 ft south, 

1,550 ft east of NW. cor. sec. 28, T. 27 S., R. 18 

E., Packwood Creek 7%' quad. Agua Sandstone 

Member of the Temblor Formation, basal conglomeratic sandstone. Collected by W. 0. Addicott, 1965.

M2632. West-trending ridge south of Bitterwater Creek, 

600 ft south, 1,400 ft east of NW. cor. sec. 27, 

T. 27 S., R. 18 E., Packwood Creek 7%' quad. 

Alt. 1,820 ft. Buttonbed Sandstone Member of 

the Temblor Formation. Collected by W. 0. Addicott, 1965.

M2633. On south side of Franciscan Creek-Miller Flats 

road, 600 ft north, 1,000 ft east of SW. cor. sec. 

36, T. 26 S., R. 17 E., Packwood Creek 7%' quad. 

Carneros(?) Sandstone Member of the Temblor 

Formation, about 1,000 ft stratigraphically below 

the base of the Media Shale Member. Same as 

USGS loc. 4941. Collected by T. W. Dibblee, Jr., 

and W. 0. Addicott, 1965.

M3280. Minor saddle in northeast-trending ridge on south 

side of Media Agua Creek, 900 ft south, 500 ft 

east of NW. cor. sec. 23, T. 28 S., R. 19 E., Las 

Yeguas Ranch 7%' quad. Wygal Sandstone Member of the Temblor Formation, 6-ft-thick fossiliferous sandstone uriconformably overlying the 

Eocene Point of Rocks Sandstone. Collected by 

Howard Sonneman and W. 0. Addicott, 1967; 

H. C. Wagner, Saburo Kanno, and W. 0. Addicott, 

1969; W. 0. Addicott, 1971.

M3281. On south side of hill 2259 just below summit, 2,200 

ft north, 1,000 ft west of SE. cor. sec. 22, T. 28 

S., R. 19 E., Las Yeguas Ranch 7%' quad. Base 

of Wygal Sandstone Member of the Temblor 

Formation. Collected by Howard Sonneman and 

W. 0. Addicott, 1967.

M3511. 8,900 ft south, 2,900 ft west of lat 35°00' N., long 

119°32'30" W. East of Cuyama Ranch 7%' quad,. 

Alt about 3,250 ft. Quail Canyon Sandstone Member of the Vaqueros Formation. Collected by J. G., 

Vedder, 1960.

M3578. About 30-40 ft above unnamed stream flowing southwestward through the SW% sec. 15, T. 29, S., 

R. 20 E., 1,100 ft north, 2,200 ft west of SE. 

cor. sec. 15, T. 29 S., R. 20 E., Carneros Rocks 

7%' quad. Wygal Sandstone Member of the Temblor Formation, collection from about 200 ft 

along strike in southwest-trending gullies. Collected by W. 0. Addicott, May 1967.

M3579. Northeast bank of southeast-flowing stream about 

15 ft above bottom, 2,200 ft south 850 ft east of

Locality Description

NW. cor. sec. 15, T. 29 S., R. 20 E., Carneros 

Rocks 7%' quad. Wygal Sandstone Member of the 

Temblor Formation. Collected by W. 0. Addicott, 

1967.

M3636. North side of Chico Martinez Creek, approximately 

2,100 ft west, 250 ft south of NE. cor. sec. 8, 

T. 29 S., R. 20, E., Carneros Rocks iVz' quad. 

Wygal Sandstone Member of the Temblor Formation. Collected by R. L. Pierce and T. W. Dibblee, 

Jr., 1967; W. 0. Addicott, 1971.

M3747. East-west-striking pelecypod biostrome on hillside 

west of Salt Creek, 850 ft north, 1,850 ft east of 

SW. cor. sec. 21, T. 10 N., R. 20 W., Pleito Hills 

IVz' quad. Pleito Formation of Wagner and Schilling (1923). Collected by W. 0. Addicott, J. G. 

Vedder, and T. W. Dibblee, Jr., 1966.

M3772. On southeast side of ridge paralleling Media Agua 

Creek about 200 feet above dirt road, 1,025 ft 

south, 200 ft east of NW. cor. sec. 23, T. 28 S., 

R. 19 E., Las Yeguas Ranch 7%' quad. Wygal 

Sandstone Member of the Temblor Formation. 

Same as USGS loc. M3280. Collected by W. 0. 

Addicott, 1968.

M3978. In bed of Temblor Creek, 1,000 ft south, 1,900 ft 

east of NW. cor. sec. 25, T. 29 S., R. 20 E., 

Carneros Rocks 7%' quad. Alt about 1,350 ft. 

Fossiliferous concretions at the top of the Wygal 

Sandstone Member of the Temblor Formation. 

Collected by H. S. Sonneman and W. 0. Addicott, 

1968.

M3979. Top of prominent ledge above southeast-trending 

segment of first creek south of Zemorra Creek, 

750 ft north, 2,750 ft west of SE. cor. sec. 16, 

T. 29 S., R. 20 E., Carneros Rocks 1%' quad. 

Alt about 2,450 ft. Wygal Sandstone Member of 

the Temblor Formation, collection from about 

300 ft along the strike of a concretionary stratum 

about 20 ft above base of the Wygal. Collected 

by H. S. Sonneman and W. 0. Addicott, 1968.

M3981. On southwest side of northwest-trending ridge, 

2,300 ft north, 800 ft west of SE. cor. sec. 25, 

T. 28 S., R. 19 E., Carneros Rocks iVz' quad. 

Alt about 1,460 ft. Lower part of the Carneros 

Sandstone Member of the Temblor Formation. 

Collected by H. S. Sonneman and W. 0. Addicott, 1968.

M3982. In bottom of north fork of Santos Creek, 1,300 ft 

north, 300 ft west of SE. cor. sec. 25, T. 28 S., 

R. 19 E., Carneros Rocks 7%' quad. Alt about 

1,300 ft. Agua Sandstone Member of the Temblor 

Formation. Collected by H. S. Sonneman and 

W. 0. Addicott, 1968; W. 0. Addicott, 1971.

M3984. Southwest side of small knoll encircled by 1,400-ft 

contour, 1,600 ft north of SE. cor. sec. 23, T. 28 S., 

R. 19 E., Las Yeguas Ranch 7 1/6' quad. Alt about 

1,330 ft. Basal 10 ft of the Wygal Sandstone 

Member of the Temblor Formation; collection 

from along 300 to 400 feet of strike of beds. 

Collected by H. S. Sonneman and W. 0. Addicott, 

1968.

M3985. On south side of Stone Corral Creek, 600 ft south, 

1,900 ft east of NW. cor. sec. 25, T. 28 S., R. 19 

E., Las Yeguas Ranch 1%' quad. Alt about 1,330
40 MOLLUSC AN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

Locality Description

ft. Wygal Sandstone Member of the Temblor 

Formation, basal 6-10 ft. Collected by H. S. Sonneman and W. 0. Addicott, 1968.

M3986. In bottom of gulch northeast of old side of MacDonalds Ranch (see USGS Bull. 406), 2,600 ft 

north 750 ft east of SW. cor. sec. 32, T. 27 S., 

R. 19 E., Shale Point 7%' quad. Alt about 1,235 

ft. About 40 ft stratigraphically above the base 

of the Buttonbed Sandstone Member of the Temblor Formation. Collected by H. S. Sonneman and 

W. O. Addicott, 1968.

M3987. Hillside west-southwest of stream junction, 500 ft 

north, 2,700 ft east of SW. cor. sec. 30, T. 27 S., 

R. 19 E., Shale Point 7%' quad. Alt about 1,350 

ft. Buttonbed Sandstone Member of the Temblor 

Formation, brown sandstone concretions occurring 

about 30 ft above the base of the member. Collected by H. S. Sonneman and W. O. Addicott, 

1968.

M3988. Hillside west-southwest of stream junction, 550 ft 

north, 2,600 ft east of SW. cor. sec. 30, T. 27 S., 

R. 19 E., Shale Point IVz' quad. Alt about 1,375- 

1,950 ft. Buttonbed Sandstone Member of the 

Temblor Formation, basal 5 ft. Collection from 

about 150 ft along strike of beds. Collected by 

H. S. Sonneman and W. 0. Addicott, 1968.

M4060. Abundantly fossiliferous conglomeratic sandstone 

exposed in low sea cliff and isolated rock on east 

side of mouth of Kirby Creek, in land parcel 52, 

Sooke 92 B/5 quad., Renfrew District, Vancouver 

Island, British Columbia. Sooke Formation. Collected by W. 0. Addicott, 1968.

M4464. On northwest plunge of small northwest-trending 

ridge, 1,250 ft north, 1,350 ft east of SW. cor. 

sec. 24, T. 28 S., R. 19 E., Las Yeguas Ranch 

IVz' quad. Agua Sandstone Member of the Temblor Formation, Crassostrea bed. Collected by 

H. S. Sonneman and W. 0. Addicott, 1968.

M4466. East wall of north-northwest-trending tributary to 

Zemorra Creek, about 50 ft above gully bottom, 

400 ft north, 1,200 ft west, of SE. cor. sec. 9, 

T. 29 S., R. 20 E., Carneros Rocks 7%' quad. 

Wygal Sandstone Member of the Temblor Formation, about 10-30 ft above the base. Collected by 

W. 0. Addicott, 1971.

M4467. In north-northwest-trending tributary to Zemorra 

Creek, 250 ft south, 950 ft west of NE. cor. sec. 

16, T. 29 S., R. 20 E., Carneros Rocks IVz' quad. 

Wygal Sandstone Member of the Temblor Formation, basal 3 ft. Collected by W. 0. Addicott, 1971.

M4468. Southwest-facing hillside on east flank of Carneros 

Rocks anticline, 3,100 ft north, 800 ft west of 

SE. cor. sec. 5, T. 29 S., R. 20 E., Carneros Rocks 

7%' quad. Wygal Sandstone Member of the Temblor Formation, lowest 20 ft. Collected by W. 0. 

Addicott, 1971.

M4469. Crest of east-trending ridge on north side of Chico 

Martinez Creek, 350 ft north, 1,200 ft east of 

SW. cor. sec. 5, T. 29 S., R. 20 E., Carneros Rocks 

IVz' quad. Alt about 1,960 ft. Wygal Sandstone 

Member of the Temblor Formation. Same as 

USGS loc. 5149. Collected by W. 0. Addicott, 1971.

Locality Description

M4470. East-northeast-trending ridge about one-fourth mile 

northwest of Carneros Creek, 450 ft north, 2,500 

ft west of SE. cor. sec. 31, T. 28 S., R. 20 E., 

Carneros Rocks 7%' quad. Alt about 1,580 ft. 

Wygal Sandstone Member of the Temblor Formation. Collected by W. 0. Addicott, 1971.

M4471. South side of road along Carneros Creek, 2,200 ft 

south, 150 ft west of SE. cor. sec. 36, T. 28 S., 

R. 19 E. [in sec. 6, T. 29 S., R. 20 E.], Carneros 

Rocks 7%' quad. Wygal Sandstone Member of the 

Temblor Formation. Collected by W. 0. Addicott, 

1971.

M4472. Near crest of 1,480-ft knoll on north side of Santos 

Creek, 550 ft north, 1,100 ft west of SE. cor. sec. 

25, T. 28 S., R. 19 E., Carneros Rocks 7%' quad. 

Wygal Sandstone Member of the Temblor Formation. Collected by W. 0. Addicott, 1971.

M4473. Crest of south-trending ridge on north side of 

Media Agua Creek (about 200 ft south of hill 

1814), 550 ft north, 2,750 ft east of SW. cor. sec. 

15, T. 28 S., R. 19 E., Las Yeguas Ranch 7%' 

quad. Wygal Sandstone Member of the Temblor 

Formation, basal 2-3 ft. Collected by W. 0. Addicott, 1971.

California University Museum of Paleontology (Berkeley) 

localities (UCMP)

B1598. At mouth of short Y-shaped gully approximately 

200 yds north of abandoned sand and gravel 

plant, 1,200 ft south, 300 ft west of of NE. cor. 

sec. 5, T. 29 S., R. 29 E., Oil Center quad. (1950 

ed.). Gray clean fine to very fine sand. Upper 

part of the Olcese Sand. Collected by W. 0. Addicott, 1953, 1954.

B1599. In second southeast-trending gully due east of hill 

933 (Bakersfield quad.), NW%NW% sec. 33, T. 

28 S., R. 29 E., Caliente quad. (1914 ed.). Upper 

part of the Olcese Sand, approximately 80 ft 

stratigraphically below the base of the Round 

Mountain Silt. Same as USGS loc. M1599. Collected by W. 0. Addicott, 1953, 1954. 

California University, Riverside, localities (UCR) 

1106. About 150 ft east of creekbed on east side of small 

shoulder which forms a bend in the creek, NE. 

cor. SWVi sec. 15, T. 29 S., R. 20 E. Dark-brownweathering, blue-gray limestone concretions in 

soft siltstone [Cymric Shale Member of the Temblor Formation], About 10-30 ft stratigraphically 

below the "basal Miocene" [Wygal Sandstone 

Member of the Temblor Formation]. Collected by 

Eric Craig (field loc. EC 89A), 1931.

1235. 150 ft north, 50 ft east of SW. cor. sec. 14, T. 29 

S., R. 20 E. Wygal Sandstone Member of the 

Temblor Formation. Collection from a 50-ft stratigraphic interval directly overying soft gray siltstone of the Cymric Shale Member. Collected by 

Eric Craig (field loc. EC 89), 1931.

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42 MOLLUSCAN BIOSTRATIGRAPHY, PALEONTOLOGY, TYPE TEMBLOR FORMATION, CALIF.

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U. S. GOVERNMENT PRINTING OFFICE : 1973 O - 493-6
INDEX

[Italic page numbers indicate major references and descriptions] 

Page

abnipta, Panopea __________________ 37, 38

Acila ___________ ___ _ ___________ 14,22

conradi _ ______________ _ _____ 3, 22

gettysburgensis _ _ ______________ 13

muta _________________________ 22

markleyensis _ ____________ 22

shumardi ____________ 4, 12, 23, 28, 30, 33

Zone ___________________ 8 

(Truncacila) muta ___________ 22; pi. 1

Acknowledgments _ 

Acrilla dickersoni ___ 

acuminata, Bruclarkia 

acutilineata, Lucina _ 

Lucina (Myrtea)

3

12

21

4

28

Lucinoma ________ 3, 4, 6, 14, 28; pis. 2, 3

acutilineatus, Phacoides _____ _ ______ 3, 28

Phacoides (Lucinoma) ___________ 28

aduncanasa, Tellina __________ _ ____ 33

Aforia ___________ _ ______________ 13

Age, Agua Sandstone Member _______ 14

Cymric Shale Member __________ 8

Temblor Formation __ _ _ ____ 1

molluscan evidence for ______ 9

Wygal Sandstone Member _ _ ___ 2,8,10

Agua Sandstone Member ___ 2, 7, 10, 13, 14 

albaria, Spisula __ ____ 29, 30; pi. 4

Alegria Formation _ ______________ 13

alexclarki, Vertipecten _ 4, 10, 17, 26; pis. 1, 2, 3 

Amiantis ______________ _ 16, 17, 35, 36; pi. 6

callosa ________________________ 35

diabloensis ____________________ 35

mathewsoni ___________ _ __ 35, 36; pi. 7

Amussiopecten sp _____________ _ ___ 3

Anadara _______________________ 16, 23, 24

strongi _______________________ 23,24

submontereyana ________________ 23, 24

(Anadara) mediaimpressa

montereyana ____________ 23

mediaimpressa submontereyana- 23 

submontereyana ____ _ _____ 23; pi. 1

(Anadara) mediaimpressa

montereyana, Anadara ___ 23 

mediaimpressa submontereyana,

Anadara _ __ _ _ _ ____ 23

submontereyana, Anadara ______ 23; pi. 1

Ancistrolepis ______________________ 13

andersoni, Leptopecten ___ _ ________ 26

Neverita _____________ _ _______ 19

angustifrons, Pitar (Katherinella) ____ 37

annulata, Lucinoma ________________ 14, 28

Antigona neglecta __________________ 35

undosa ________________________ 35

(Artena) mathewsonii __________ 35

neglecta ___________________ 35

(Ventricola) undosa _ __ __ _ _ __ 35

Antropora ________________________ 17

sp _ ______ ____ ______ _ 21

Apolymetis sespeensis __________ _ ___ 34

twinensis _____________________ 34

vancouverensis __________________ 34

Area (Scapharca) submontereyana ____ 23

Archaeogastropoda _________________ 17

Arcidae ___ __ _ __ _____ . _ __ _ _ 23

Arcoida _____________ ________ _ 23

Page

arctata, Macoma ____________ 14, 33; pi. 5

Macoma (Psammacoma) _______ 33

Tellina _______________________ 33

wynoocheensis, Macoma _________ 33

arnoldi, Crenomytilus ___________ 24; pi. 1

(Artena) matheivsonii, Antigona _____ 35 

neglecta, Antigona ____________ 35

attenuata, Spisula ramonensis _______ 29

B

barkeriana, Bruclarkia __________ 3, 4, 21, 22

santacruzana, Bruclarkia _____ 10, 21, 22

"Barren" shale member of

Temblor Formation __ __ 8 

Bathybembix _ __ ________ _ ____ _ __ 13

bodegensis, Tellina _________________ 32

borealis, Lucina ____________ _ _____ 28

branneri, Calicantharus ___________ 20; pi. 9

Chlamys _____ -___ ___________ 26

Pecten ____ _ __________________ 4

(Chlamys) _________________ 26

Bruclarkia ___________________ 9, 10, 14, 21

acuminata __________ _________ 21

barkeriana _ ___ _____ __ __ 3,4,21,22

santacruzana ____________ 10, 21, 22

columbiana __ _______ 8,10,12,21,22 

gravida _ _ ____________________ 21

oregonensis __________ _ ________ 22

santacruzana ___________________ 21

seattlensis _ _____ 3, 4, 10, 13, 21, 22; pi. 9

Buliminella curta 

Bullia clarki ___

C

Calicantharus _______________ _ ___ ZO

branneri __________________ _ 20; pi. 9

dalli _______________________ 20; pi. 9

kernensis __________ _ _________ 20

woodfordi __________ _ _________ 20

California, Oliva ____________ _ _____ 3

californica, Pitar __________________ 37

Pitar (Katherinella) _ _____ 37; pi. 6 

Plectofrondicularia ______________ 15

callosa, Amiantis __________________ 35

Calyptraea ___ _ _ ____ ___ ___ 14, 17

coreyi _ _ _____ _ _____ __ 18

diegoana ____________________ 17; pi. 8

mammilaris vancouverensis ______ 18

washingtonensis ________________ 17, 18

Calyptraeidae ___________________ _ 17

canalis, Polinices __________ _ ______ 19

Cancellaria _______________________ 14

carnarosensis, Yoldia _____________ _ 23

Carneros Sandstone Member ___ _ _ 7, 14, 15

Cerithiid _____________________ 17; pi. 8

Cerithiidae ____

Chionc lineolata

mathewsonii

panzana __

inhitneyi __

Chlamys ______

branneri __ 

hertleini __ 

sespeensis _

17

37

35

3

36

26

26

13

3

Page 

26 

10 

15 

25 

32 

12

(Chlamys) branneri, Pecten _ ___ 

sespeensis, Pecten _____ _______

Cibicides floridanus _________ ____

pseudoungerianus evolutus _______

clallamensis, Tellina ______ _______

clarki, Bullia ----------------------

dementia __________ _ - - _ 16, 36

pertenuis _____________ _____ 36

(Egesta) pertenuis _____ 36; pis. 7, 8

coalingensis, Crenomytilus ____ _____ 24

cocoaensis, Uvigcrina _ ___________ 9

columbiana, Bruclarkia ______ 8, 10, 12, 21, 22

condoni, Epitonium ________________ 19, 12

conradi, Acila ______________ _____ 3, 22

cooperi tenuissima, Yoldia ___ ___ _ 22 

cooperii, Yoldia ____________________ 22

supramontereyensis, Yoldia _______ 22

coreyi, Calyptraea __________ _____ 18

Correlation of Cymric Shale Member__ 9 

crassicardo, Lyropecten _______ ____ 3

Crassostrea ______________ 6,14,16,25,27

cldridgei ynezana _____________ 27; pi. 2

sookensis ______________________ 27

vagucrosensis _____ ___________ 14

sp ______________________ 13,27 

Crenomytilus ___________________ 14, 16, 24

arnoldi ____________________ 24; pi. 1

coalingensis ___________________ 24

expansus ___________________ 24; pi. 4

loeli ____________ _ __ __ _______ 24

Crepidula ____________________ ___ 18

princeps __________ __________ 18

sookensis _____________________ 18

unga.no, __________ _______ 18; pi. 8

cryptolineata, Securella ___________ 37; pi. 6

curta, Buliminella _________________ 9

Cyclamina incisa __________ ______ 15

Cyclas permacra __________________ 28

Cymric oil field __________________ 6

Cymric Shale Member _______ 2, 6, 7, 8, 15

dalli, Calicantharus _______________ 20; pi. 9

Molopophorus - _______________ 12

Searlesia ____________________ 20

Dentaliidae ___________________ 38 

Dentalium ______________________ 38

laneensis ____________________ 38; pi. 8

radiolineata ___________________ 38

(Fissidentalium) laneensis _______ 38

diabloensis, Amiantis ______________ 35

dickersoni, Acrilla ________________ 12

Pecten ___________________ 25

(Pecten) ______________ 25

diegoana, Calyptraea _____________ 17; pi. 8

Trochita ___________________ 17

diegoensis, Lucina ________________ 10

Diplodonta harfordi ________________ 29

disjuncta, Thyasira ________________ 10

Dosinia _________________________ 16,36

mathewsonii ___________________ 36, 37

ponderosa ____________________ 15

whitneyi ____________________ 36,37

(Dosinia) whitneyi ________ 36; pis. 6, 7

45
46 INDEX

Page

Dosinia Continued

(Dosinidia) mathewsoni ________ 36

whitneyi ________________ 36

(Dosinia) whitneyi, Dosinia,- ____ 36; pis. 6, 7

(Dosinidia) mathewsoni, Dosinia ____ 36

whitneyi, Dosinia ____________ 36

E

Echinophoria ___________________ 13

apta zone ____________________ 13

rex ______________________ 19,22

Zone ________________ 12,13,16

Egesta __________________ 36

(Egesta) pertenuis, dementia _ 36; pis. 7, 8 

eldridgei, Ostrea ________________ 27

ynezana, Crassostrea _______ 27; pi. 2

Ostrea __________ __ 27

emacerata, Tellina _________________ 32

Tellina (Oudardia) ________ 32; pi. 4 

Epistomina ramonensis __________ 9

Epitonium condoni ______________ 10, 12

estrellana, Panopea ______________ 38

evolutus, Cibicides pseudoungerianus-_ 25 

excavata. Here ______________ 27; pi. 3

Here (Here) __________________ 27

Lucina ____________________ 27

(Here) ___________________ 27

excentricus, Galerus _____________ 17

expansus, Crenomytilus _________ 24; pi. 4

Mytilus __________________ 24

mathewsoni ____________ 24

Fauna, Wygal Sandstone Member-_ 2, 5, 6, 15 

Favites _______________________ 16, 17

Felaniella _____________________ 29

harfordi __________________ 29; pi. 4

Ficidae _____________________ 20

Ficus _______________________ 16,20

modesta ___________________ 20; pi. 9

pyriformis __________________ 20

(Trophosycon) gesteri ________ 20

Fish scales, Cymric Shale Member ___ 9

Santos Shale Member _______ 9

Temblor Formation _____________ 9

(Fissidentalium) laneensis, Dentalium-- 38 

floridanus, Cibicides _______________ 15

Foraminifera, biostratigraphic study of_ 1 

Cymric Shale Member _________ 9

depth range for ________ 15

Santos Shale Member, depth

range for __ __ _ 15 

Temblor Formation _____________ 9

frustra, Spisula pittsburgensis _______ 29

G

gabbi, Molopophorus _______________ 33

Galerus excentricus ______________ 17

Gastropoda ____________ _____ 17

Gastropods ________ _________ 6, 14

Gaviota Formation __ _ 10 

gesteri, Ficus (Trophosycon) _________ 20

gettysburgensis, Acila ___________ 13

Glossaulax ________________________ 19

(Glossaulax) thomsonae, Neverita __ 19; pi. 9 

gravida, Bruclarkia ______________ 21

gravidus, Solen __________________ 30; pi. 4

Gyroidina soldanii _________________ 15

H

harfordi, Diplodonta _______________ 29

FelanieUa ______________ 29; pi. 4

hemphilli, Spisula _________________ 30

Page

Here ___________ _ - 16,27 

excavata __ ___ -- _____ 27; pi. 3

(Here) excavata ______ 27

(Here) excavata, Here _____________ 27

excavata, Lucina ________ __ 27

Richthofeni, Lucina ___ 27 

richthofeni, Phacoides ___________ 27

hertleini, Chlamys ____ _-- - 13

Heteromacoma ______ _ 34

rostellata _______ 6, 34; pis. 5, 6

sespeensis ___ ____ - - 34

( Heteromacoma) vancouverensis,

Macoma _ _ ________ 34

incisa, Cyclamina _ _______ _ 15

inezana, Turritella ___ ____ ___ 3, 4, 8

Introduction _ 1 

Invertebrates, depth ranges of ______ 14

jacksonensis, Uvigerina 

Jewett Sand _________

K

Kalayoldia _______________ 22,23

(Kalayoldia) tenuissima, Yoldia ___ 22; pi. 1 

Katherinella _______________ _ 37

(Katherinella) angustifrons, Pitar ____ 37

calif or nica, Pitar ______ __ 3 7; pi. 6

Kelletia _________________ __ ______ 16,21

sp ___________________ 21 

kennerlyi, Venus ___________ ____ 36

kernensis, Calicantharus ___________ 20

kernianum, Trophosycon _________ _ 3

laevis, Tegula ___ _ - 17 

laneensis, Dentalium ____________ 38; pi. 8

Dentalium (Fissidentalium) ___ 38 

Leptopecten ______________________ 14, 26

andersoni __ _______ _____ 26

sp ____________________ 26; pi. 1

lincolnensis, Perse ________________ 12

lineolata, Chione __ ____ _________ 37

Liracassis ____________________ 13

Lithology, Temblor Formation __ 1, 4

Wygal Sandstone Member 5, 6

Locality, Wygal Sandstone Member ___ 4

loeli, Crenomytilus ____________ _ 24

lorenzana, Olequahia __________ 8, 10, 12

Pitar _________________________ 37

Turritella _____________________ 10

Lucina acutilineata ________ ______ 4

borealis __________________ __ 28

diegoensis ______________ _____ 10

excavata _____________________ 27

richthofeni ___________________ 27

(Here) excavata ________ _____ 27

Richthofeni ________________ 27

(Myrtea) acutilineata ____ 28

Lucinidae ______ __ 27

Lucinoma ___________________ 14,15,28

acutilineata ______ 3, 4, 6, 14, 28; pis. 2, 3

annulata ______________________ 14, 28

(Lucinoma) acutilineatus, Phacoides __ 28 

Lyropecten crassicardo _____________ 3

M

Macoma _________________________ 33

arctata ______________ 14, 33; pi. 5

wynoocheensis _____________ 33

nasuta _______________________ 31,33

Macoma Continued 

piercei ___ _. 

secta _____ . 

sespeensis ____. 

wynootcheensis .

Page

_________ 31

_________ 31 

_________ 34 

_________ 33

(Heteromacoma) vancouverensis--- 34 

(Psammacoma) arctata _________ 33

Macrocattista pittsburgensis _ _ 12 

Macrochlamis magnolia ___ _____ 14

Mactridae _____ 29 

magnolia, Macrochlamis ____ -- 14

malibuensis, Tegula __ __ ____ 17

mammilaris vancouverensis, Calyptraea- 18 

markleyensis, Acila muta ____________ 22

mathewsoni, Amiantis _______ 35, 36; pi. 7

Dosinia (Dosinidia) ___________ 36

expansus, Mytilus __ ______ _- 24

mathewsonii, Antigona (Artena) _ __ 35 

Chione _______ - _ - 35

Dosinia ______________________ 36, 37

mediaimpressa montereyana, Anadara

(Anadara) ___ _ _ 23 

submontereyana, Anadara

(Anadara) _________ 23

merriami, Siphonalia ________ _____ 12

Mesogastropoda ___ _ - 17 

Metis rostellata _________________ 34

vancouverensis --____--_____--- 34

Miltha ___________________ 14,15,16,28,29

sanctaecrucis ___ _ _ _ 29 

xantusi __________________ 29

(Miltha) sanctaecrucis ________ 28; pi. 3

(Miltha) sanctaecrucis, Miltha _____ 28; pi. 3

sanctaecrucis, Phacoides ________ 28

modesta, Ficus ______________ 20; pi. 9

Mollusks ______________________ 8 

Agua Sandstone Member ___ _ 14 

biostratigraphic study of ________ 1

Cymric Shale Member _ 9 

provinces _ 16 

Santos Shale Member 13 

Temblor Formation __________ 1, 6

annotated references to ____ 3

tuff member of Kirker Formation __ 13

Wygal Sandstone Member _____ 7, 10, 15

Molopophorus _____________________ 13

dalli _________________________ 12

gabbi ____________________ 33

stephensoni ________________ 33

Monterey Shale _ 4 

montereyana, Anadara (Anadara)

mediaimpressa _________ 23

muta, Acila _____ ____ ____ 22

Acila (Truncacila) ________22; pi. 1

markleyensis, Acila ____________ 22

Myidae _______________________ 37 

Myoida _______________________ 37 

(Myrtea) acutilineata, Lucina ______ 28

Mytilidae ___________________ 24

Mytiloida ___________________ 24

Mytilus ________ _____________ 14

expansus ____________________ 24

mathewsoni expansus __________ 24

N

na&uta, Macoma ________________ 31, 33

Natica ____________________16, 18, 19; pi. 8

posuncula _________________ 19

teglandae ________________ 19

vokesi __________________ 19

(Natica) ______________________ 17, 19

(Natica), Natica ___________________ 17, 19

Naticidae __________________ 18

neglecta, Antigona ____________ 35

Antigona (Artena) ____________ 35

Neogastropoda ____ ___________ 20

Neptuneidae __ _____ _ 20
INDEX 47

Page 

nevadensis, Tellina __________ 30, 31, 32

Neverita _________________________ 16, 19

andersoni _________________ 19

recluziana _________________ 19

thomsonae __________________ 19

(Glossaulax) thomsonae ________ 19; pi. 9

nodifera, Siphogenerina ______________ 9,15

Nuculanidae ___ ____________ 22 

Nuculidae ___ ______ 22 

Nusuloida _ ______ 22

O

obliquum, Sinum __________________ 19

occidentalis, Spisula _____________ 30

ocoyana, Tellina _____ ________ 31, 32

Olcesia ________________ ___ 16,17,30

(Olcesia) piercei, Tellina _____ 31; pis. 4, 5

Olequahia ___________________ 8

lorenzana ________________ 8, 10, 12

Oligocene vertical oscillation of San

Joaquin basin _______ 15

Oliva California _ _ _______ 3 

oregona, Yoldia _ ______ 23

Yoldia (Portlandia) _____________ 22

oregonensis, Bruclarkia __________ 22

Tellina _______________________ 32

(Peronidia) _ ______ 32 

Ostrea ___________ _ ______ 3

eldridgei __________________ 27

ynezana ______________ 27

sp 4 

Ostreidae ___ ___ ________ 27 

Oudardia _______________________ 32

(Oudardia) emacerata, Tellina ____ 32; pi. 4

Paleobathymetry _ 14 

Panope ramonensis ______________ 37

Panopea ____________________ 37

abrupta ___ _ _ _ ______ 37, 38 

estrellana ____ __ _______ 38

ramonensis _________________ 37; pi. 8

(Panopea) ramonensis _________ 37

(Panopea) ramonensis, Panopea _____ 37

panzana, Chione _______________ 3

patulus, Pectunculus ____________ 28

Pecten ________________________ 24,25

branneri ___________________ 4

dickersoni __________________ 25

sanctaecruzensis _____ 6, 10, 24, 25

(Chlamys) branneri ___________ 26

sespeensis _____ _________ 10

(Pecten) dickersoni _ _______ 25 

sanctaecruzensis _________24; pi. 2

sp 26 

(Pecten) dickersoni, Pecten _________ 25

sanctaecruzensis, Pecten _____ 24; pi. 2

Pectinidae ____ _____- 24

Pectunculus patulus ______________ 28

Pelecypoda ___ _ 22 

Pelecypods _________________ 6,10,14 

permacra, Cyclas _____________ ___ 28

Peronaea _______________ ____ 31

Peronidia _____ 31

(Peronidia) oregonensis, Tellina ______ 32

perrini, Vertipecten _____________ 10, 14, 26

Perse lincolnensis __________________ 12

pertenuis, dementia _____ _____ __ 36

dementia (Egesta) ________ 36; pis. 7, 8

Venus ________________________ 36

Phacoides ____________________ 3,4,21

acutilineatus _________________ 3, 28

richthofeni ____________________ 27

(Here) richthofeni ___ 27 

(Lucinoma) acutilineatus _________ 28

(Miltha) sanctaecrucis _________ 28

Page

Phacoides reef ___ _______________ 4

Phacoides sand ____________________ 2,4,8

piercei, Macoma __________________ 31

Tellina _________________ 30,31,32 

(Olcesia) _______________ 31; pis. 4, 5

Pitar ____________________________ 34,37

californica ______ __ _ 37

lorenzana __________________ 37

(Katherinella) angustifrons ______ 37

californica ____________ 37; pi. 6

sp ______________________ 37; pi. 6 

pittaburgensis, Macrocattista ________ 12

frustra, Spisula ___ ____ _ 29 

Plectofrondicularia californica ________ 15

 vaughani ___________________ 9, 15

Pleito Formation ____________ 9, 11, 12, 13 

Point of Rocks Sandstone ___________ 4, 6

Polinices __________________ 17, 18, 19; pi. 9

canalis ____________________ 19

victoriana _________ _________ 19

ponderosa, Dosinia ________________ 15

Poromya _ _ _____ 34

teglandae ____________________ 34

(Portlandia) oregona, Yoldia _________ 22

posuncula, Natica ________________ 19

princeps, Crepidula _______________ 18

(Psammacoma) arctata, Macoma ____ 33

Pseudocardium ___________________ 29

sp __ __________________ 29; pi. 5 

pseudoungerianus evolutus, Cibicides __ 25 

Pterioida ____________________ 24 

pyriformis, Ficus _______________ 20

Q

Quail Canyon Sandstone Member of

Vaqueros Formation ____ 13

R

radiolineata, Dentalium ____ 

ramonensis attenuata, Spisula 

Epistomina _____________

Panope _____________

38

__ 29 

9

37 

Panopea ________________ 37; pi. 8

(Panopea) ____ _____ 37

Spisula _________ __ _ 30; pi. 4

recluziana, Neverita _____________ 19

rex, Echinophoria _____________ 19, 22

Richthofeni, Lucina. (Here) ________ 27

richthofeni, Lucina ______ _______ 27

Phacoides ___ ___ 27 

(Here) ____________________ 27

rostellata, Heteromacoma _____ 6, 34; pis. 5, 6

Metis _____________________ 34

rushi, Spisula ___ _ ______ 30; pi. 4

S

Salt Creek Shale ______

San Emigdio Formation 

San Lorenzo Formation 

San Ramon Sandstone _ 

sanctaecrucis, Miltha __

_______ 6 

_______ 9

_______ 10

_______ 13 

_______ 29

Miltha (Miltha) _____________ 28; pi. 3

Phacoides (Miltha) -________ 28 

sanctaecruzensis, Pecten _______ 6, 10, 24, 25

Pecten (Pecten) ______________ 24; pi. 2

santacruzana, Bruclarlcia ___________ 21

Bruclarkia barkeriana ________ 10, 21, 22

Santos Shale Member ________ 2, 9, 13, 15

(Scapharca) submontereyana, Area ___ 23 

Scaphopoda ______________ ______ 38

scopulosum, Sinum _____________ 19; pi. 9

Searlesia ___ __ __ __ 20

dalli _________________________ 20

seattlensis, Bruclarkia- 3, 4, 10, 13, 21, 22; pi. 9

Page

secta, Macoma __________ _______ 31

Securella ___ ___ _- _______ 37

cryptolineata _________ _____ 37; pi. 6

Sespe Formation __ - _____ 6

sespeensis, Apolymetis ______________ 34

Chlamys ____ 3

Heteromacoma _______ _ 34

Macoma ______ ____ 34

Pecten (Chlamys) ______________ 10

shumardi, Acila _________ 4,12,23,28,30,33

Sinum ___ _________ ____ _ 19

obliquum _______ __ ___ 19

scopulosum _____ __ ____ 19; pi. 9

Siphogenerina nodifera _ _______ _ 9, 15

transversa ____ ______ ____ 9

Siphonalia ________ _____ 16, 21

merriami ____ _____________ _ 12

sp ___________ 21; Pi- 9 

Soda Lake Sandstone Member 13 

soldanii, Gyroidina _________________ 15

Solen _________ _ _ - 30

gravidus _ 30; pi. 4 

Solenidae ___ 30 

sookensis, Crassostrea ______ ___ 27

Crepidula _____ __ 18

South Belridge oil fields ___ 4 

Spisula __________ 17, 29, 30; pi. 4

albaria __________________ 29, 30; pi. 4

hemphilli ____________________- 30

occidentalis _______ ____ _ _ 30

pittsburgensis frustra ____ ____ 29

ramonensis ______ ___ ____30; pi. 4

attenuata ___________- _ 29

rushi ______________________30; pi. 4

sp _______________________ 14 

stephensoni, Molopophorus _________ 33

strongi, Anadara ______-______ 23, 24

submontereyana, Anadara __________ 23, 24

Anadara (Anadara) _______ _ 23; pi. 1

(Anadara) mediaimpressa _____ 23

Area (Scapharca) ______________ 23

supramontereyensis, Yoldia _______ 23

Yoldia cooperii ____________ 22

Systematic descriptions 16

teglandae, Natica ___ _ _____ 19 

Poromya ____________ ________ 34

Tegula _________ 14, 17; pi. 8

laevis ______ ____ _ _______ 17

malibuensis ___________________ 17

Tellina _________________-_______ 30

aduncanasa ________ _______ 33

arctata _______ _ _________ 33

bodegensis ____ __________ _ 32

clallamensis ______ ________ _ 32

emacerata ____ ____ _____ 32

nevadensis __________ 30, 31, 32

ocoyana ____________________ 31, 32

oregonensis ___________________ 32

piercei _____________________ 30,31,32

tenuilineata ___________________ 32

townsendensis _ __ _____ 32; pi. 6

vancouverensis _______________ 33; pi. 4

(Olcesia) piercei ___ _____ 31; pi. 4, 5

(Oudardia) emacerata ________ 32; pi. 4

(Peronidia) oregonensis ________ 32

(Tellinella) tenuilineata ____ 32; pi. 5

Tellinella __________.._________ 16,32

(Tellinella) tenuilineata, Tellina-__ 32; pi. 5

Tellinidae ______________________ 30

Temblor Formation, microfaunal

sequence 6 

provinicial age and correlation___ 6 

stages of _ 7 

stratigraphy _ 4
48 INDEX

Page

Temblor Range 4 

Temblor Stage _ 1 

Temblor Zone __________________ 1 

temblorensis, Yoldia _______ ____ 23

tenuilineata, Tellina __ ____ ___ 32

Tellina (Tellinella) ___________ 32; pi. 5

temiissima, Yoldia ____________ 22, 23

Yoldia cooperi _ 22 

(Kalayoldia) __________ 22; pi. 1

Thickness, Cymric Shale Member ____ 9

Temblor Formation __________ 1, 4

Wygal Sandstone Member _____ 5 

thomsonae, Neverita _____________ 19

Neverita (Glossaulax) _____ _ 19; pi. 9

Thyasira disjuncta ________ ____ 10

Tivela ____________________________ 15

townsendensis, Tellina __________ 32; pi. 6

transversa, Siphogencrina ________ 9

Trochidae ______________________ 17 

Trochita diegoana _ ______ __ 17 

Trophosycon kernianum ___________ 3

(Trophosycon) gesteri, Ficus ________ 20

Truncacila ________________ 22

(Truncacila) muta, Acila ______ 22; pi. 1

tumeyensis, Uvigerina ___________ 9

Turcicula ____________________ 13

Turritella ______________________ 11, 13, 31

inezana ______ _ _____ 3, 4, 8

zone __ ___ ____ 12

lorenzana ________________ 10

twinensis, Apolymetis __________ 34

Type area, Temblor Formation _______ 1

Type locality, Temblor Formation ___ 4

U

Unconformity, Temblor Formation __ 4 

Wygal Sandstone Member ____ 6, 15

Page

undosa, Antigona __ __ __ 35 

Antigona (Ventricola) _______ 35

ungana, Crepidula _________ 18; pi. 8

Ungulinidae __ _- 

Uvigerina cocoaensis

jacksonensis ___.

tumeyensis ___.

vicksburgensis

Vancouver'ensis, Apolymetis _________

Calyptraea mammilaris __ 

Macoma (Heteromacoma) _______

Metis ______ _ _____

Tellina _________ __ 3S

Vaqueros Formation _______________

Vaqueros Sandstone ________________

Vaqueros Stage _______- _ 

vaquerosensis, Crassostrea ___ ___ 

vaughani, Plectofrondicularia ______

Veneridae _______ _ - ______

Veneroida _ _ _________________

(Ventricola) undosa, Antigona _____

Venus kennerlyi _________ __

perteniiis __________________

Vertipecten _________ ___ 10,

alexclarki ________ 4, 10, 17, 26; pis.

perrini ______________ 10,

yneziana _______ ___ ____

vicksburgensis, Uvigerina _________

victoriana, Polinices _______ _____

vokesi, Natica ____ _____ _____

W

29

9

9

34 

18 

34 

34

; pi. 4

10, 14

10

8,10 

14

9, 15 

35 

27

35

36

36

16,26

1,2,3

14,26

10

9

19

19

Wagonwheel Formation _ 10 

washingtonensis, Calyptraea _______ 17, 18

Page

whitneyi, Chione _ __ 36 

Dosinia _____________________ 36, 37

(Dosinia) ___________ 36; pis. 6, 7

(Dosinidia) _____ _ _____ 36

woodjordi, Calicantharus ____ _____ 20

Wygal Sandstone Member __ __ 2, 4,10

corals _ ____ ___ ___ 16

genera of tropical aspect __ 14

Lucinoma-Heteromacoma bed __ 6

wynoocheensis, Macoma arctata ______ 33

wynootcheensis, Macoma _________ 33

xantusi, Miltha _______________ 29

ynezana, Crassostrea eldridgei ____ 27; pi. 2 

Ostrea eldridgei ____________ 27

yneziana, Vertipecten ___________ 10

Yoldia _______________________ 22 

carnarosensis _____________ 23

cooperi tenuissima __________ 22

cooperii __________________ 22

svpramontereyensis __________ 22

oregona _ _ 23 

supramontereyensis _________ 23

temblorensis _____________ 23

tenuissima ________________ 22, 23

(Kalayoldia) tenuissima _____ 22; pi. 1

(Portlandia) oregona __ _____ 22

Zoogeography and paleoclimatology___ 15
PLATES 1-9

[Contact photographs of the plates in this report are available, at cost, from U.S. 

Geological Survey Library, Federal Center, Denver, Colorado 80225]
PLATE 1

[Specimens are from the Wygal Sandstone Member of the Temblor Formation unless otherwise indicated]

FIGURES 1, 18. Crenomytilusl cf. C.? arnoldi (Clark) (p. 24).

1. Length 83 mm, height 35 mm. USNM 646511. USGS loc.

M3578. 

18. Length 120 mm, height 68 mm. USNM 646512. USGS loc.

M3979. 

2, 3, 5, 8. Yoldia (Kalayoldia) tenuissima Clark (p. 22).

2. Length 45 mm, height 24.5 mm, USNM 646513. USGS loc. 

M3578.

3. Length 48 mm, height 25.5 mm. USNM 646514. USGS loc.

M3578. 

5. Length 43 mm, height 23.5 mm. USNM 646515. USGS loc.

M3578.

8. Length 31 mm, height 16 mm. USNM 646516. USGS loc. 

6622. Round Mountain Silt, Kern River area, California, 

middle Miocene. 

4, 15. Acila (Truncacila) muta Clark (p. 22).

4. Length 12 mm, height 10.5 mm. USNM 646517. USGS loc.

M4471. 

15. Length 12.2 mm, height 10.5 mm. USNM 646518. USGS loc.

M4466. 

6, 7, 11, 16, 17. Anadara (Anadara) submontereyana (Clark) (p. 23).

6. Length 30 mm, height 20 mm. USNM 646519. USGS loc. 

M3978.

7. Length 32 mm, height 22.5 mm. USNM 646520. USGS loc.

M3978. 

11. Length 20 mm, height 13 mm. USNM 646521. USGS loc.

M3978. 

16, 17. Length 26 mm, height 17 mm. USNM 646522. USGS

loc. M3772. 

9, 10, 13. Vertipecten alexclarki Addicott, n. sp. (p. 26).

9. Length 24 mm, height 28 mm. USNM 646523. USGS loc.

M3280. 

10. Height 42 mm, thickness 13.5. USNM 646524. USGS loc.

M3636. 

13. Height of fragment 33 mm. USNM 646525. USGS loc.

M3280. 

12. Yoldia (Kalayoldia) cf. Y. (K.) cftrnarosensis Clark (p. 23).

Length 32 mm. USNM 646526. USGS loc. M1596. Olcese Sandstone, Kern River area, California, middle Miocene. 

14. Leptopectenl sp. (p. 26).

Height 24 mm. USNM 646527. USGS loc. M3280.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 1

.-£i

v wre

, CRENOMYTILUSt, LEPTOPECTEN, VERTIPECTEN, YOLDIA
PLATE 2

[All specimens are from the Wygal Sandstone Member of the Temblor Formation]

FIGURES 1, 3, 5, 8, 9. Vertipecten alexclarki Addicott, n. sp. (p. 26).

1. Length 89 mm, height 80 mm. USNM 646528. USGS

loc. M3285. 

3. Length 63 mm, height 82 mm. USNM 646529. USGS

loc. M3772. Specimen deformed. 

5. Height 40 mm. USNM 646530. USGS loc. M3579.

8. Length 66 mm, height 69 mm. USNM 646531. USGS 

loc. M3281.

9. Height 68 mm. USNM 646532. USGS loc. M3280. 

2, 10. Crassostrea eldridgei ynezana (Loel and Corey) (p. 27).

2. Immature specimen. Length 41 mm, height 45 mm.

USNM 646533. USGS loc. M3280. 

10. Length 60 mm, height 101 mm. USNM 646534. USGS

loc. M3280. 

4, 7. Pecten (Pecteri) sanctaecruzensis Arnold (p. 24).

4. Length 65 mm. USNM 646535. USGS loc. M4467. 

7. Height 36 mm. USNM 646536. USGS loc. M4467. 

6. Lucinoma acutilineata (Conrad) (p. 28).

Length 35 mm, width 33 mm. USNM 646537. USGS loc. 

M3280.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 2

 !_ 

t

CRASSOSTREA, LUCINOMA, PECTEN, VERTIPECTEN
PLATE 3

[All specimens are from the Wygal Sandstone Member of the Temblor Formation]

FIGURES 1, 4. Vertipecten alexclarki Addicott, n. sp. (p. 26).

1. Height 84 mm. USNM 646538. USGS loc. M3281. 

4. Length of fragment 66 mm. USNM 646539. USGS loc. M3985. 

2. Crenomytilust cf. C.? arnoldi (Clark) (p. 24).

Length 81 mm, height 37.5 mm. USNM 646540. USGS loc. M3978. 

3, 7. Lucinoma acutilineata (Conrad) (p. 28).

3. Length 33 mm, height 31.5 mm. USNM 646541. USGS loc.

M3280. 

7. Length 34 mm, height 29.5 mm. USNM 646542. USGS loc.

M3280. 

5, 10. Miltha (Miltha) sanctaecrucis (Arnold) (p. 28).

5. Length 65 mm, height 64 mm. USNM 646543. USGS loc.

M3579. 

10. Length 68 mm, height 65 mm. USNM 646544. USGS loc.

9432. 

6, 8, 9. Here excavata (Carpenter) (p. 27).

6. Length 16 mm, height 15.5 mm. USNM 646545. USGS loc. 

M3578.

8. Length 17 mm, height 17 mm. USNM 646546. USGS loc. 

M3578.

9. Length 17.5 mm, height 17.5 mm. USNM 646547. USGS loc. 

M3578.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 3

9 10 

CRENOMYTILUS1, HERE, LUCINOMA, MILTHA, VERTIPECTEN
PLATE 4

[Specimens are from the Wygal Sandstone Member of the Temblor Formation unless otherwise indicated]

FIGURE 1. Spisula n. sp.? (p. 30).

Length 91 mm, height 68 mm. USNM 646548. USGS loc. M3579. 

2, 7. Felaniella harfordi (Anderson) (p. 29).

2. Length 19.5 mm, height 17.5 mm. USNM 646550. USGS loc.

M3280.

7. Length 24 mm, height 21.5 mm. USNM 646551. USGS loc. M3280. 

3, 4, 8. Spisula cf. S. albaria (Conrad) (p. 29).

3. Length 47 mm, height 35.5 mm. USNM 646552. USGS loc. M3578.

4. Length 37 mm, height 28.5 mm. USNM 646553. USGS loc. M3578. 

8. Length 36 mm, height 28 mm. USNM 646554. USGS loc. M3979.

5. Spisula ramonensis Packard (p. 30).

Length 49 mm, height 37 mm. USNM 646555. USGS loc. M3280.

6. Spisula albaria (Conrad) (p. 29).

Length 46.5 mm, height 36.5 mm. USNM 646556. USGS loc. M1802,

Astoria Formation, middle Miocene, Oregon. 

9. Solen aff. S. gravidus Clark (p. 30).

Height 25.5 mm. USNM 646557. USGS loc. M3280. 

10, 12. Tellina (Olcesia) piercei (Arnold) (p. 31).

10. Height 49 mm. USNM 646558. USGS loc. M3978. 

12. Length 63 mm, height 43.5 mm. USNM 646559. USGS loc. M3578. 

11. Tellina (Oudardia) emacerata Conrad (p. 32).

Length 35 mm, height 20 mm. USNM 646560. USGS loc. M3578.

13. Tellinal cf. T. Vancouverensis Clark and Arnold (p. 33). 

Height 19 mm. USNM 646561. USGS loc. M3578.

14. Spisula cf. S. rushi Wagner and Schilling (p. 30).

Length 83 mm, height 63.5 mm. USNM 646562. USGS loc. M3979.

15. Crenomytilus expansus (Arnold) (p. 24).

Length 116 mm, height 60 mm. USNM 646549. USGS loc. 9427.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 4

15

CRENOMYTILUS, FELANIELLA, SOLEN, SPISULA, TELLINA, TELLINAt
PLATE 5

[Specimens are from the Wygal Sandstone Member of the Temblor Formation unless otherwise indicated]

FIGURES 1, 3, 6, 9-11. Heteromacoma rostellata (Clark) (p. 34).

1. Suborbicular form. Length 55.5 mm, height 47 mm.

USNM 646563. USGS loc. M3280. 

3. Suborbicular form. Length 51 mm, height 46 mm.

USNM 646564. USGS loc. M3280. 

6. Suborbicular form. Length 53.5 mm, width 45 mm.

USNM 646565. USGS loc. M3281. 

9. Elongate form. Length 57.5 mm, height 42 mm. USNM

646566. USGS loc. M3772.

10. Subquadrate form. Length 65 mm, height 44 mm. 

USNM 646567. USGS loc. M3280.

11. Subquadrate form. Length 67 mm, height 55 mm.

USNM 646568. USGS loc. M3280. 

2, 8. Tellina (Tellinella) tenuilineata Clark (p. 32).

2. Length 53.5 mm, height 29 mm. USNM 646569. USGS

loc. M3578. 

8. Length 53 mm, height 28.5 mm. USNM 646570. USGS

loc. 9432. 

4, 7. Macoma arctata (Conrad) (p. 33).

4. Length 56.5 mm, height 37 mm. USNM 646571. USGS

loc. M3280. 

7. Length 56 mm, height 38 mm. USNM 646572. USGS

loc. M3280. 

5. Pseudocardiuml sp. (p. 29).

Length 45 mm, height 42.5 mm. USNM 646573. USGS loc.

M4466. 

12, 13. Tellina (Olcesia) piercei (Arnold) (p. 31).

12. Length 74.5 mm, height 55 mm. USNM 646574. USGS 

loc. M1599. Olcese Sand, Kern River area, California, 

middle Miocene.

13. Length 76 mm, height 51 mm. USNM 646575. USGS 

loc. M1599. Olcese Sand, Kern River area, California, middle Miocene.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 5

12 13 

HETEROMACOMA, MACOMA, PSEUDOCARDIUMt, TELLINA
PLATE 6

[All specimens are from the Wygal Sandstone Member of the Temblor Formation]

FIGURES 1, 3, 9, 12, 13. Dosinia (Dosinia) whitneyi (Gabb) (p. 36).

1. Length 71 mm, height 61 mm. USNM 646576. USGS

loc. 9432. 

3. Length 44.5 mm, height 48.5 mm. USNM 646577.

USGS loc. M3280. 

9. Length 48 mm, height 46 mm. USNM 646578. USGS

loc. M3280. 

12, 13. Length 58 mm, height 58.5 mm. USNM 646579.

USGS loc. M3280. 

2, 4, 14. Heteromacoma rostellata (Clark) (p. 34).

2. Subquadrate form. Height 54 mm. USNM 646580.

USGS loc. M3280. 

4. Elongate form. Length 74 mm, height 47 mm. USNM

646581. USGS loc. M3280.

14. Suborbicular form. Length 74 mm, height 60 mm. 

USNM 646582. USGS loc. M3280.

5. Securella cf. S. cryptolineata (Clark) (p. 37).

Length 40 mm, height 32 mm. USNM 646583. USGS loc. 

M3280.

6. Amiantis n. sp.? (p. 36).

Length 50 mm, height 38.5 mm. USNM 646584. USGS loc. 

M3578.

7. Tellina cf. T. townsendensis Clark (p. 32).

Length 32 mm, height 17.5 mm. USNM 646585. USGS loc.

M3578.

8, 11. Pitar (Katherinella) cf. P. (K.) californica (Clark) (p. 37). 

Length 67 mm, height 41.5 mm. USNM 646586. USGS

loc. M3280. 

10. Pitar sp. (p. 37).

Length 58 mm, height 45.5 mm. USNM 646587. USGS loc. 

M3978.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 6

13 14

AMIANTIS, DOSINIA, HETEROMACOMA, PITAR, SECURELLA, TELLINA
PLATE 7

[Specimens are from the Wygal Sandstone Member of the Temblor Formation unless otherwise indicated]

FIGURES 1, 4, 8, 13, 14. Amiantis mathewsoni (Gabb) (p. 35).

1. Length 54 mm, height 61.5 mm. USNM 646588. USGS

loc. M3280.

4, 8. Length 64.5 mm, height 60.5 mm. USNM 646589. 

USGS loc. M3978.

13. Hinge, natural size. USNM 646590. USGS loc. M3978.

14. Length 67 mm, height 60.5 mm. USNM 646591. USGS

loc. M3772. 

2, 3, 11. Amiantis n. sp.? aff. A. diabloensis (Anderson) (p. 35).

2, 3. Length 54.5 mm, height 46.5 mm. USNM 646592. 

USGS loc. 6627. Olcese Sand, Kern River area, 

California, middle Miocene.

11. Hinge, natural size. UCMP 14090. UCMP loc. B1599. 

Olcese Sand, Kern River area, California, middle 

Miocene. 

5, 10. Dosinia (Dosinia) whitneyi (Gabb) (p. 36).

5. Length 45.5 mm, height 42 mm. USNM 646593. USGS

loc. M3280.

10. Hinge, natural size. USNM 646594. USGS loc. M3772. 

6, 7. Amiantis n. sp.? (p. 36).

6. Length 59 mm, height 43 mm. USNM 646595. USGS 

loc. M3578.

7. Length 54 mm, height 41 mm. USNM 646596. USGS

loc. M3578. 

9, 12. dementia (Egesta) pertenuis (Gabb) (p. 36).

9. Length 65.5 mm, height 54 mm. USNM 646597. USGS

loc. M3280.

12. Length 72.5 mm, height 53.5 mm. USNM 646598. 

USGS loc. 9432.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 7

AMIANTIS, CLEMENTIA, DOSINIA
PLATE 8

[All specimens are from the Wygal Sandstone Member of the Temblor Formation] 

FIGURES 1, 3, 19. dementia (Egesta) pertenuis (Gabb) (p. 36).

1. Length 70.5 mm, height 62 mm. USNM 646599. USGS

loc. M4466. 

3. Length 71 mm, height 62.5 mm. USNM 646600. USGS

loc. M4466. 

19. Length 71.5 mm, height 60 mm. USNM 646601. USGS

loc. M3578. 

2, 4. Tegula n. sp. (p. 17).

2. Height 17 mm, width 19.5 mm. UCR 1235. UCR loc. 1235. 

4. Height 20.5 mm, width 21.5 mm. USNM 646602. USGS

loc. M3578. 

5. Cerithiid? (p. 17).

Height 19 mm. USNM 646603. USGS loc. M3578. 

6, 7, 9, 11, 15, 16. Crepidula cf. C. ungana Dall (p. 18).

6. 15. Width 25.5 mm. USNM 646604. USGS loc. M3280.

7. Length 28.5 mm, width 20 mm. USNM 646605. USGS loc.

3979. 

9, 11, 16. Length 37.5 mm, width 20 mm. USNM 646606.

USGS loc. M3281. 

8, 10, 17, 18. Calyptraea diegoana (Conrad) (p. 17).

8, 10. Height 10.5 mm, width 22 mm. USNM 646607. USGS

loc. M3280. 

17, 18. Height 19 mm, diameter 48 mm. USNM 646608. USGS

loc. M3281. 

12, 13. Natica (Natica) n. sp. (p. 19).

12. Height 21 mm, width 20.5 mm. USNM 646609. USGS loc. 

M3280.

13. Height 28 mm, width 25.5 mm. USNM 646610. USGS loc.

M3280. 

14. Dentalium laneensis Hickman (p. 38).

Length 23.5 mm, width 8 mm. USNM 646611. USGS loc.

M3772. 

20. Panopea ramonensis (Clark) (p. 37).

Length 92 mm, height 52.5 mm. USNM 646612. USGS loc. 

M3280.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 8

19 20 

CALYPTRAEA, CERITHIW?, CLEMENTIA, CREPWULA, DENTALIUM, NATICA, PANOPEA, TEGULA
PLATE 9

[Specimens are from the Wygal Sandstone Member of the Temblor Formation unless otherwise indicated]

FIGURES 1, 2, 8, 9, 14. Bruclarkia seattlensis Durham (p. 21).

1. Height 46 mm, width 33 mm. USNM 646613. USGS 

loc. M3979.

2. Height 45.5 mm, width 30.5 mm. USNM 646614. USGS

loc. M3772. 

8, 9. Height 30.5 mm, width 24.5 mm. USNM 626615.

USGS loc. M3772. 

14. Height 33 mm, width 26 mm. USNM 646616. USGS

loc. M3280.

3. Bruclarkia barkeriana forma sanctacruzana (Arnold) (p. 21). 

Height 46 mm, width 28.5 mm. UCMP 36556. UCMP loc. 

B1598. Olcese Sand, Kern River area, California, 

middle Miocene.

4. Neverita (Glossaulax) thomsonae Hickman (p. 19).

Height 32.5 mm, width 38.5 mm. USNM 646617. USGS loc.

M3978. 

5, 6. SiphonaHa! sp. (p. 21).

Height 25 mm, width 18 mm. USNM 646618. USGS loc.

M3280. Specimen deformed. 

10. Polinices n. sp.? (p. 19).

Height 29 mm, width 29 mm. USNM 646619. USGS loc.

M3280. Specimen deformed. 

7, 11, 12. Kelletial sp. (p. 21).

7. Height 32 mm, width 30 mm. USNM 646620. USGS

loc. M3280.

11, 12. Width 28 mm. USNM 646621. USGS loc. M3772. 

13. Calicantharus cf. C. branneri (Clark and Arnold) (p. 20).

Height 31.5 mm, width 23 mm. USNM 646622. USGS loc.

M4471. 

15, 20, 21. Bruclarkia gravida (Gabb) (p. 21).

15. Lectotype. Height 32 mm, width 21 mm. ANSP 4345. 

San Ramon Sandstone, Contra Costa County, Calif., 

early Miocene ( ?).

20, 21. Height 42 mm, width 29 mm. ANSP 4345a. San 

Ramon Sandstone, Contra Costa County, Calif., early 

Miocene (?). 

16, 17. Sinum cf. S. scopulosum (Conrad) (p. 19).

16. Height 20 mm, width 22 mm. USNM 646623. USGS 

loc. M3578. Specimen deformed.

17. Height 17 mm, width 20 mm. USNM 646624. USGS

loc. M3578. 

18, 19. Ficus cf. F. modesta (Conrad) (p. 20).

18. Height 32 mm, width 22 mm. USNM 646625. USGS 

loc. M3578. Specimen deformed.

19. Height 33.5 mm, width 28.5 mm. USNM 646626. USGS

loc. M3978. Specimen deformed. 

22, 23. Bruclarkia columbiana (Anderson and Martin) (p. 8).

Height 43.5 mm, width 32.5 mm. UCR 1106. UCR loc. 1106. 

Cymric Shale Member of the Temblor Formation, Oligocene. 

24. Calicantharus dalli (Clark) (p. 20).

Height 53.5 mm, width 36 mm. USNM 646628. USGS loc. 

M3772.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 791 PLATE 9

10

11

13

20 21 22 23 24 

BRUCLARKIA, CALICANTHARUS, FICUS, KELLETIAINEVERITA, POLINICES, SINUM, SIPHON ALIA?