Zoogeography of Holocene Ostracoda 

off Western North America and 

Paleoclimatic Implications 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 

Zoogeography of Holocene Ostracoda 

off Western North America and 

Paleoclimatic Implications 

By PAGE C. VALENTINE 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 

Holocene ostracode distribution related 

to marine climatic conditions off the 

coasts of the United States and Baja 

California) Mexico; paleoclimatic 

interpretation) Pliocene and Pleistocene 

marine deposits" southern California 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1976 
UNITED STATES DEPARTMENT OF THE INTERIOR 

THOMAS S. KLEPPE, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress Cataloging in Publication Data 

Valentine, Page C 

Zoogeography of Holocene Ostracoda off western North America and paleoclimatic implications. 

(Geological Survey professional paper ; 916) 

Bibliography: p. 

Supt. of Docs. no.: I 19.16:916 

1. Ostracoda, Fossil. 2. Paleontology-Recent. 2. Paleobiogeography-Pacific coast. I. Title. II. Series: United 

States. Geological Survey. Professional Paper ; 916. 

QE817.08V29 565' .33'091643 74-34076 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 

Stock Number 024-001-02760-7 
Abstract ________________ ------- ___ ------- ______ _ 

Introduction ____________________________________ _ 

Acknowledgments _______________________________ _ 

Ostracode zoogeography off the west coast of the 

United States and Baja California, Mexico ------- Previous studies _____________________________ _ 

Holocene collections ---------------------------

Distribution of marine organisms --------------

Marine climate off the west coast of the United 

States and Baja California, Mexico _________ _ 

Holocene ostracode distribution patterns --------

Shelf assemblages defined by cluster analysisFaunal character of provinces and provincial boundaries -------------------------

Marine paleoclimates of selected Pliocene and Pleistocene units of southern California -----------------· Fossil collections ____________________________ _ 

Stratigraphy and age of Pliocene and Pleistocene 

units _____ --- __ ---------------------------

San Diego Formation ---------------------

San Pedro Formation and Palos Verdes Sand_ 

CONTENTS 

Page 

1 Marine paleoclimates-Continued 

1 Stratigraphy and age of Pliocene and Pleistocene, 

1 units-Continued 

Santa Barbara Formation -----------------

~ Foxen Mudstone and Careaga Sandstone ----

2 Comparison of Holocene and fossil assemblages --

3 Faunal composition of fossil units ----------

3 Cluster analysis of Holocene and fossil 

samples ------------------------------- 11 Paleotemperature determinations based on 

12 zoogeographic evidence ----------------------

19 Paleoclimatic implications of fossil assemblages 

from southern California --------------------

21 San Diego Formation ---------------------

Foxen Mudstone and Careaga Sandstone -----

27 Lomita Marl and Timms Point Silt Members 

27 of the San Pedro Formation --------------

Santa Barbara Formation -----------------

29 Palos Verdes Sand ---------------""--------

29 Discussion ---------------------------------------

29 References cited ----------------------------------

ILLUSTRATIONS 

PLATE 1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

FIGURES 1-4. 

Ambostracon. 

A mbostracon. 

[Plates follow index] 

Ambostracon, Buntonia, Coquimba, new genus F, and Puriana. 

"Cytheretta," Cytheropteron, H ermanites, Pulmilocytheridea, and Sahnia. 

Kangarina, "Kangarina," Paracytheridea, and Pontocythere. 

Hemicytherura, "Loxoconcha," and Loxocorniculum. 

Aurila, "Aurila," and Loxoconcha. 

Aurila. 

Cytheromorpha, Radimella, and "Radimella." 

Munseyella, Palmenella, and Pectocythere. 

Caudites, Orionina, Palaciosa, and Triebelina. 

Basslerites, Cythere, and Hemicythere. 

Cativella, Costa?, Neocaudites?, "Paijenborchella," and "Trachyleberis." 

"H emicytkere." 

Locality maps for Holocene shelf samples and fossil units from 

Page 

30 

30 

31 

31 

31 

32 

36 

36 

37 

37 

42 

43 

43 

45 

Page 

1. Cape Flattery, Wash., to the California-Oregon border ---------------------------------- 3 

2. California-Oregon border to Point Aii.o Nuevo, Calif ----------------------------------- 4 

3. Point Aii.o Nuevo, Calif., to San Diego, Calif____________________________________________ 5 

4. San Diego, Calif., to south of Cabo San Lucas, Baja California, Mexico ------------------- 6 

5. Map showing ostracode faunal provinces and areas of upwelling off the Pacific coasts of the United 

States and Baja California --------------------------------------------------------------- 13 

6. Map of yearly minimum sea temperatures off the Pacific coasts of the United States and Baja California --------------------------------------------------------------------------------- 14 

7. Map of yearly maximum sea temperatu!"es off the Pacific coasts of the United States and Baja California --------------------------------------------------------------------------------- 15 

III 
IV CONTENTS 

Page 

FIGURE 8. Dendrogram of Holocene ,sample clusters ------------------------------------------------------- 20 

TABLE 

9. Map showing ostracode faunal provinces and climatic zones of the eastern Pacific ---------------- 21 

10. Dendrogram of Holocene and fossil sample clusters --------------------------------------------- 33 

11. Diagram showing interactiolljs of temperature limits of a cryophile and a thermophile --------------- 35 

12. Diagram showing modern temperatures tolerances for ostracode species occurring in the San Diego 

Formation ----------------------------------------------------------------------------- 38 

13. Diagram showing yearly temperature ranges in ostracode faunal provinces of the eastern Pacific and 

possible yearly tempetrature ranges in fossil units------------------------------------------- 39 

14-19. Diagrams showing modern temperature tolerances for ostracode species occuTring in: 

14. Foxen Mudstone --------------------------------------------------------------------- 40 

15. Careaga Sandstone ------------------------------------------------------------------ 41 

16. Timms Point Silt Member of the San Pedro Formation ---------------------------------- 41 

17. Lomita Marl Member of the San Pedro Formation ------------------------------------- 42 

18. Santa Barbara Formation _________________ -- __ ----- _________ --- ____________________ -- 44 

19. Palos Verdes Sand ------------------------------------------------------------------- 45 

TABLES 

1. Location and source of Holocene and foss.il samples __ -------------------------------------------

2. Latitudinal ranges of 15-minute samples ------------------------------------------------------

3. Alphabetical list of ostracode species included in cluster analyses --------------------------------

4. Holocene geographic ranges and fosstil occurrences of ostracode species in the study area -----------

5. Distribution of inner sublittoral ostracode species and their occurrence in faunal provinces of the eastern Pacific ----------------------------------------------------------------------------- 6. Register of fossil localities ------------------------ ________________________ -------------------

7. Faunal diversity of fossil units and percentage of fauna having living representatives -------------

Page 

7 

16 

17 

22 

2'5 

28 

32 
ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF 

WESTERN NORTH AMERICA AND PALEOCLIMATIC IMPLICATIONS 

By pAGE C. vALENTINE 

ABSTRACT 

Holocene shelf samples (255) from off the west coasts of 

the United States and Baja California, Mexioo, yielded 341 

spe·cies of ostracodes. The distributions of biogeographically 

diagnostic specie.s are established. Sp,ecies pre,sent within 

each 15-minute segment of latitude constitute samples which 

are compared on the basis of their faunal composition. Cluster 

analysis of 110 samples containing 192 ostracode species 

from the continental shelf between 21 o 43' N. and 48 o 24' N. 

permits recognition of four faunal provinces which are similar to modern molluscan provinces of the eastern Pacific. The 

existence of subprovinces is also evident from this analysis. 

Faunal distributions and faunal province•s are principally 

controlled by marine climate, especially water temperature. 

8e.asonal climatic changes and the influence of the California 

Current, in conjunction with intense seasonal upwelling, are 

responsible for the configuration of marine isotherms off 

the·se coasts. The faunal discontinuity at the Oregonian-Californian provincial boundary (35°30' N.) is characterized by 

range terminations of many northward ranging thermophile·s, 

and nine important southern genera do not occur north of 

this boundary; many southward ranging cryophiles terminate 

their ranges at the Galifornian-Surian boundary (28°15'N.). 

Large, well-pres·erved fossil ostracode assemblages were 

studied from six Pliocene or Pleistocene formations from 

southern California. These are the San Diego Formation, 

San Pedro Formation (Lomita Marl and Timms Point Silt 

Members), Palos Veres Sand, Santa Barbara Formation, 

Foxen Mudstone, and the Care.aga Sandstone. Of 123 diagnostic species found in these units, only 19 are not known 

to be living today. Although mo·st fossil species, therefore, 

have living representative•s, a cluster analysis reveals no 

marked similarity between living and fossil assemblages, and 

this disagreement is probably the result of an alteration in 

the marine climate. Comparison of the temperature tolerance's 

of species common to the Holocene and to fossil assemblages 

yields yearly temperature maxima and minima that could 

have occurred during deposition of the fossil units. These paleotemperature determinations indicate that all fo,ssil assemblages are repre,sentative of a warm temperate marine climate which was broadly similar but not neceSISarily identical 

to that present today in the Californian faunal province 

offshore of the fossillocaliHes. 

INTRODUCTION 

The first part of this study is an investigation of 

the zoogeography of the modern podocopid Ostracoda found on the shelf off the west coasts of the 

United States ~and Baja California, Mexico. The 

ostracodes of the west coast of North America are 

not well known, and this report is ·an attempt to 

establish the geographic distribution of important 

ostracode species, to identify distributional patterns, 

and to determine factors influencing these patterns. 

The results of this study are intended to aid in establishing a basis for future studies involving ostracode 

zoogeography, paleocology, biostratigraphy, and 

taxonomy. 

The second part of this report seeks to apply the 

results of the zoogeographic study to an interpretation of the paleoclimates of selected Plioc:ene and 

Pleistocene marine deposits of southern California 

which contain large, well-preserved ostracode ass~embla.ges. The large size of the total fauna (373 species), only a fraction of which have been described, 

precludes a taxonomic study at this time. Many important species are illustrated, however, and illustrated specimens have been deposited in the collections o[ the U.S. National Museum, Washington, 

D.C. 

ACKNOWLEDGMENTS 

I wish to exp·res~s my appreciation to J. W. Valentine, University of California, Davis, and to W. 0. 

Addicott and J. E. Hazel of the U.S. Geological Survey for their constructive criticism of the 

man useri:pt. 

Many penple have assisted me in obtaining samples., 1and ·sample sources a.re listed in table 1. I 

would like to thank in particular G. A. Fowler, 

formerly of Oregon 8tate University; R. L. Kolpack, 

University of Southern Californi~a; F. B Phleger, 

Scripps Institution of Oceanography; E. E. Welday, 

California Division of Mines and Geology; and the 

Departm·ent of Oceanography, University of Washington, for generously providing me with samples 

from their collections and for allowing me to use 

1 
2 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

their laboratories during my visits. I also wish to 

thank R. J. Enrico and G. S. Zumwalt of the Department of Geology, University of California at Davis 

for furnishing me with many valuable samples. I am 

grateful to both J. C. Ingle, Stanford University, for 

permitting me to examine L. W. LeRoy's type specimens, and to Dustin Chivers of the California Academy of Sciences for allowing me to examine T. Skogsberg' s types. 

The scanning electron micrographs were taken by 

R. W. Wittkopp and R. L. Gertman of the Department of Geology at Davis and printed by Kenji Sakamoto of the U.S. Geological Survey, and their assistance is greatly appreciated. I am indebted to Lanci 

Valentine who assisted in processing many of the 

samples and drafted the original illustrations. 

OSTRACODE ZOOGEOGRAPHY OFF THE WEST 

COAST OF THE UNITED STATES AND 

BAJA CALIFORNIA, MEXICO 

PREVIOUS STUDIES 

In contrast to other groups, notably the Mollusca 

and the Foraminifera which have been intensively 

studied on the west coast, few investigations of the 

ostracode assemblages of this region have been undertaken. Most studies of Holocene forms are of a 

local nature, restricted to assemblages of bays and 

estuaries, chiefly in Baja California and Central 

America. 

The following papers have listed or described ostracode species from off the west coasts of Mexico 

and Central America. Benson (1959) reported on 

the fauna (46 species) of Todos Santos Bay, Baja 

California, and Benson and Kaesler (1963) on that 

(16 sp,ecies) of an estuary and a lagoon in the northeastern Gulf orf California. Swain (1967) treated 

the os,tracodes (91 species) of the Gulf of California; McKenzie and Swa,in (1967) described the 

fauna (52 species) of Scammon Lagoon, Baja California, and Swain and Gilby (1967) the fauna (37 

species) of Corinto Bay, Nicaragua. Hartmann 

(1953, 1956, 1957, 1959) studied ostracodes (55 species) from estuaries and coastal regions of El Salvador, and Ishizaki and Gunther (1974) reported on 

31 species from the Gulf of Panama. 

As a result of these studies, the fauna of the 

southern regions is bette1r known than that to the 

north off the United States and Canada. Juday 

(1907) described two species from the San Die,go 

area. LeRoy (1943a, b; 1945) reported on 27 species 

found in Pliocene and Pleistocene deposits of southern California and also living along that coast. 

Skogsberg (1928, 1950) studied seven species of the 

Monterey Peninsula, and Watling (1970) two species from Tom1ales Bay. Lucas (1931) and Smith 

( 1952) recorded 32 species from the Vancouver 

Island region of British Columbia. 

With the exception of Swain's (1967) Gulf of 

California paper, the studies cited above all deal 

with local asse~mblages, and while they are a valuable contribution to an understanding of elements of 

the west coast fauna, no zoogeographic study of 

broad areal extent had been conducted until Swain 

(1969) analyzed samples from off the west coasts of 

the United States and Baja California. Swain's report, however, is based on only 40 samples ( 94 species) and is of a preliminary nature. In a recent 

paper, Swain and Gilby (1974), using essentially the 

same samples studied by Swain in 1969, have described 80 species (16 of them new) and indicated 

their distribution off the west coasts of the United 

States, Baja California, and Nicaragua. 

Fossil ostracode species have been listed or described only from California and Alaska. In addition 

to LeRoy's papers, mentioned above, Crouch (1949) 

repnrted on 29 species from the Pliocene (and Pleistocene) of southern California; Triebel (1957) deseribed five new species and Hazel (1962) two new 

species from the Pleistocene of that region. Hazel 

(in Addicott, 1966) listed 15 species from the late 

Pleistocene of central California. Swain (1963) 

treated 43 species from the Pleistocene of the Arctic 

Coas,tal Plain of Alaska, and Schmidt (~963, 1967) 

and Schmidt and Sellmann (1966) also reported on 

several forms from the Pleistocene of Alaska. 

In the area presently under study, which includes 

the shelf off the west coasts of the United States and 

Baja California and a coastline of about 2,000 miles, 

only 141 species have been described from the Holocene, Pleistocene, and Pliocene, the total fauna of 

which is approxima~ely 400 species. 

The following investigations of Holocene and fossil ostracode assemblages from the eastern Pacific 

and coasts of North, Central, and South America, 

the Caribbean Sea, and the coasts of Japan were 

used in identifying the species found during this 

study: Benson (1959) ; Benson and Kaesler (1963) ; 

Bold (1963) ; Coryell and Fields (1937); Crouch 

(1949) ; Hanai (1957a, b, c, 1959a, b, 1961, 1970) ; 

Hartmann (1953, 1956, 1957, 1959, 1962, 1965) ; 

Hazel (1962) ; Ishizaki (1966, 1968, 1969, 1971) ; 

Ishizaki and Gunther, 1974; Juday (1907); Leroy 

(1943 a, b; 1945) ; Lucas (1931) ; McKenzie and 

Swain (1967) ; Morkhoven (1963) ; Ohmert (1968, 
HOLOCENE COLLECTIONS 3 

1971) ; Pokorny (1968, 1969, 1970) ; Schmidt (1963, 

1967) ; Schmidt and Sellmann (1966) ; Skogsberg 

(1928, 1950) ; Smith (1952) ; Swain (1963, 1967, 

1969) ; Swain and Gilby (1967, 1974) ; Triebel 

(1957) ; and Watling (1970). 

HOLOCENE COLLECTIONS 

Holocene samples for this study were collected 

from the continental shelf off the west coasts of the 

United States and Baja California from about 21 °43' 

N. to 48°24' N. (figs. 1-4). The size of the area 

under study made it impossible to procure uniform, 

original samples for this report. Consequently, the 

s~amples were assembled from many sources and 

were collected and processed in various ways. It is 

felt that the large number of samples (255) from 

which ostracodes were identified provides adequate 

coverage for the purpose of this study. The collections are chiefly from the inner sublittoral, although 

several samples we.re collected from greater depths, 

and some are from tide pools, intertidal areas, and 

beach swash zones. The source, geographic location, 

and depth of the samples used in this study are presented in table 1. 

The number of Holocene species distinguished is 

341. Many of these species are rare, however, and 

their distributions are not well known. As this study 

is conce·rned with and based on species distributions, 

the inclusion of poorly known sp·ecies would distort 

any distributional patterns which exist. Therefore, 

192 well-known species, all of which are living off 

the coast today, are utilized in the zoogeographic 

study. Living or recently dead specimens were found 

in most s~amples examined. Groups not treated in the 

study include xestoleberids, paradoxostomatids, 

Cypridacean ostracodes, and the genus Cytherura. 

DISTRIBUTION OF MARINE ORGANISMS 

Studies of the distribution patterns of shallowwater organisms (chiefly Mollusca, but also other 

marine invertebrates) indicate that distinctive assemblages are characteristic of particular re.gions of 

the shelf. These regions, or faunal provinces, have 

been identified on continental shelves throughout the 

world. Those of the northeastern Pacific have recently been reviewed and analyzed by J. W. Valentine (1966, 1973). Hazel (1970) traces the historical 

development orf the faunal p·rovince concept and 

treats the provinc,es of the North Atlantic in detail. 

Provincial boundarie•s are recognized where shelf 

assemblages, diagnostic over a broad geographic 

area, alter their composition because of the termina126° 

=>-. 

JOB VICTORIA 

-

107 ... : .. ·.· · ..106 

-

105 

-

104 

-

103 

- ,::·::-::: 

102 

-

101 

•=·== <j_j •••. ·····= ==. < } / ll L =·=·· VA, H: N\~Tl),N ::: >> ...... < 

-

100 

99 

I ·=·.··•u=····=,· < ........ ::··. ::-::-::.::::: 

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.---------------~---1· :·:=.::· .·.·: ~£'. -l 

98 ,. 

PACIFIC 1•-= .... ,·:: 

':·:: ····~ 97 .···· ... · .. 

··· .. ·{·8.-20 . ·,.:,,· 96 

{ ! y 21~23 .... , 

::: 

.·.·.·. 95 OCEAN ; 

••••• 

24• ·.':•·• 

94 :::::. 

1:·:1: : ·: -::.·.:.·.:>.<: ( it{'F,( rt ~· 

.. 93 .. 25 · ..... 26 '·:: 

92 

91 27 ••.•• 

90 ·· ...... ····· .. . 

89 28 ... 29• •••• ,N ~ ON 

I 87 15-minute sam.ple ::::::JJ 

30::_32 , .... ··•·•• 16. Holocene sample 

33-36.. number 

88 

,..-· .. : f '=·=: ······,·····•:=': ···. · 100::fathom! 

.3H L ·=· :,.:,::=,-=: ::., :: 

.

4j:(tape Blanco 

87 

86 

.43• ~ A A -:·:::::·::··:•.·:··::::>::::-::::>>:11 

6 ' ~Ill!::: 

jj~~~==~ 49:·lllllli'llll'l~l~~l~~iiiiill 84 50,.~~· 01111

:' .t<:I•M.t:..~ 

83 

42° 

85 

FIGURE !.-Locations of Holocene sample stations, Cape Flattery, Wash., to the California-Oregon border. For exact 

location see table 1. 

tion of species ranges and the app,earance of forms 

ranging in frnm neighboring provinces. These boundarie·s mark distributional dis~continuities which are 

controlled by environmental factors. 

Ma.rine invertebrates cannot control their body 

temperature, and the rates of their physiological 

processes are directly influenced by the ambient 
4 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

126° 

82 

81 

80 

79 

78 

77 

76 

75 

74 

73 

72 

71 

70 

69 

------- 68 

67 

'"'t\ 

';!;;-

Cl 

-~ 

-Cl 

0 

Cl 

t:1 

';!;;-

z 

124° 122° 

42° 

40° 

mony in which the processes operate. Water temperature is considered the fundamental factor limiting species distribution (Gunter, 1957; Kinne, 1963; 

J. W. Valentine, 1973); its importance is demonstrated by the fact that marine sublittoral province 

boundaries are often located where isotherm convergence causes a steep temperature gradient to occur seasonally or annually within a short geographic 

distance. Such a temperature gradient may act as a 

survival harrier if it incorporates the lethal temperature of a species. Water temperature may also 

act as a repopulation barrier to organis.ms whose 

reproduction and larval development must occur in a 

temperature range which lies within the range of 

their maximum temperature tolerances (Hutchins, 

1947). 

Other environmental factors also influence the distribution of marine organis.ms and especially the 

composition, structure, and function of marine co·mmunities (Margalef, 1968; J. W. Valentine, 1971, 

1973). These factors include salinity, turbulence, 

turbidity, substrates, light intensity, and nutrient 

supply. Since these determinants are developed to 

differing degrees along the shelves, it follows that 

community attributes should also vary in this direc66 ,...".,.,'""" "'""'"··==···::.;.;;..,. 3s· tion ; therefore, faunal provinces could be charac0 

I I I I 

0 

65 

64 

63 

62 

I I· 

50 MILES 

I 

50 KILOMETRES 

EXPLANATION 

72 15-minute sample 

60. Holocene sample 

number 

100 fathoms 

terized by their community types as well as by their 

faunal assemblages, which are really collections of 

communities (J. W. Valentine, 1968, 1973). This 

ideal has not been achieved, however, perhaps because few quantitative _determinations of community 

composition and response to environmental factors 

have been made. Indeed, faunal province assemblages are at present not readily characterized by 

their relation to any of the physical factors mentioned above with the exception of water temperature. Other factors have less direct influence on most 

r----------+------------1 36• species ranges over the broad areas and diverse 

habitats of the continental shelves. 

FIGURE 2.-Locations of Holocene sample stations, CaliforniaOregon border to Point Afio Nuevo, Calif. For exact location, see table 1. Dashed lines between 15-minute samples 

indicate ostracode faunal (sub) province boundaries. 

wat.er tempe·rature. An increase in temperature of 

10° C can c1ause a twofold to threefold increase in the 

~ates of these processe·s in marine poikilotherms. 

And as the rates of different metabolic processes 

may not increas:e or decrease in concert, a marked 

change in water temperature can disrupt the harThe role of the marine climate in influencing the 

establishment of faunal provinces is evident in that 

each geographic faunal province is associated with a 

climatic term expressing in a qualitative way the 

nature of the ma.rine climate in that province. From 

south to north the northern hemisphe.re climatic 

zones are: tropical, subtropical, warm-temperate, 

Jnild-temperate, cold-temperate, subfrigid, and 

frigid. Depending on the interactions of factors controlling the marine environment, one or more of 

these zones (and provinc,es) may not be developed. 

Seemingly a,s a result of the influence of marine temperature, then, distributional patterns of marine 
122° 

58 

57 

------- .... 56 

111,112,1 ~.5 

55 

54 

53 

52 

51 

50 

PACIFIC 

49 

48 

OCEAN 

47 

46 

45 

44 

43 

DISTRIBUTION OF MARINE ORGANISMS 

120° 

·. 

'·····. 

(~\· ....... ~~:·:~·.-.:: 

0 

118• 

4

5 

15

Holocene -minute sample sample : ! I illl!lli ~[~~~······ number 

)( Fossil locality 

100 fathoms 

157-1 

168,169, 173 •. 180,18h .182 °

0 

···~~.! 

193,1 

San Diego Formation : 

195-200 

50 MILES .... · 

50 KILOMETRES 

1

1 I 

201-20~ .. ~ ... 

38• 

36° 

34° 

.. 

FIGURE 3.-Locations of Holocene sample stations, Point Aiio Nuevo, Calif., to San Diego, Calif. For exact location, see 

table 1. Dashed lines between 15-minute samples indicate ostracode faunal (sub) province boundaries. 

5 
6 

I 

ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

42 

41 

40 

39 

38 

--

111° 

' .. ·· .. 

32 

31 

30 - 29 

28 

27 

___ r~:r;-221 . 26 

25 

24 

23 

224 227'i> Qc. 

228- \4fun· ~ <'~ 

~ 1.5.' ;.;.::•=·=•·•=•· 0 

233 ·236. . .::·::.: 0 b,-.. ~0 · .... 22 

237, 238 , f < . =•===• 7<'- .... 21 239 242r "" 

I 

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··....... \<~ t ~ .. ··> . ~\ ~' 7 

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..... · .. 

18 

17 

16 

15 

Cabo San Lazaro ..: I •. '"\\. --- 14 13---

ll_ 

77 

.. 

243-

10 

9 

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7 

6 ------- 5 

4 

3 

2 

·· ... _e~ 

... :· ... · ... ; . · .. •,,' ··.:: -.. 

·. \ 

=···· .. ' ·=·=·· 

( 

\? 

--

. ' 

108° 

-

} 

.... ·. 

· . 

=·:-· 

25~~ 

:···· .. ····255 . '\) ·. . . 

30° 

27" 

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n------1-------~------L--~-.. ~: _=j21" 

...... 

I 

0 

I I I I I 

I 200 MILES ~~-L~--~~~--L~----~1 

0 2po KILOMETRES 

I 

I 

EXPLANATION 

32 15-minute sample 

253. Holocene sample 

number 

.......... 100 fathoms 

FIGURE 4.-Locations of Holocene sample stations, San Diego, Calif., to south of Cabo San Lucas, Baja California, Mexico. 

For exact location, see table 1. Dashed lines between 15-minute samples indicate ostracode faunal (sub) province boundaries. 
DISTRIBUTION OF MARINE ORGANISMS 7 

TABLE 1.-Location and source of Holocene samples from the shelf off the west coast of the United States and Baja California, Mexico, and 16 Pliocene or Pleistocene samples from southern CaliforniaSource.- UW: 

SB: 

F: 

CQR: 

FP: 

EZ, RE, ZUM: 

BHL: 

CDM: 

USC: 

Samples obtained from the collections of the Univ. 

Washington through the courtesy of the Dept. 

Oceanography. Collections made in 1967 on Oceaneer Cruise No. 14 by T. L. Burrett (1967). 

Sample obtained from Sarah Barnes, Dept. Oceano- graphy, Univ. Washington. 

Samples obtained from the collections of G. A. Fow- ler, Dept. Oceanography, Oregon State Univ. 

Samples obtained from W. N. Orr, Dept. Geology, 

Univ. Oregon. 

Sample obtained from F. B Phleger, Scripps In- stitution of Oceanography. 

Samples collected in 1972-73 by R. J. Enrico and G. S. Zumwalt, Dept. Geology, Univ. California, 

Davis. 

Samples obtained through the courtesy of Pat Wilde and Ken Leslie from the collections of the Hy- draulic Engineering Lab, Univ. California, Berk- eley. 

Samples obtained through the courtesy of E. E. Welday from the collections of the California Di- vision of Mines and Geology. 

Samples obtained from the collections of the Univ. 

Southern California through the courtesy of R. L. Kolpack, Dept. Geological Sciences. Collections were 

made in 1970-71 on cruises of the Velcro IV sup- ported by National Science Foundation Grant GB- 8206, the National Sea Grant Program, U.S. Dept. Commerce Grant GH-89, and the Western Oil and Gas Association. 

M, V, Z: Samples collected in 1972-73 by Page Valentine and Lanci Valentine. 

TZ, C: Samples obtained from the collections of the Scripps Institution of Oceanography through the courtesy of F. B Phleger, Geo ogical Rnsearch Div;sion. TZ samples were collected in 1962 by R. R. Lank- ford (1962), and C samples were collected by J. R. Curry, Scripps Institution of Oceanography. JH: Samples collected by John Holden, N.O.A.A. Re- search Laboratory and obtained from J. E. Hazel, U.S. Geological Survey. 

USGS Cenozoic sample localities Mf2165-2180=Pliocene and Pleisto- cene of southern California collected in 1971 by Page Valentine and J. W. Valentine, Department of Geology, University of California, 

Davis; J. H. Lipps of the same department provided sample Mf2170. 

Depth.-

B=beach swash zone. 

IT=intertidal. 

TP =tide pool. 

Sample Location 

No. Source 

l_ __ _ 2 ___ _ 3 ___ _ 4 ___ _ 5 ___ _ 6 ___ _ 

7 ___ _ 8 ___ _ 

9 ___ _ 10 ___ _ 

11_ __ _ 12 __ , __ 13 ___ _ 

14 ___ _ 15 ___ _ 16 ___ _ 17 ___ _ 

18 ___ _ 19 ___ _ 20 ___ _ 21_ __ _ 22 ___ _ 23 ___ _ 24 ___ _ 25 ___ _ 

26 ___ _ 27 ___ _ 

28 ___ _ 29 ___ _ 30 ___ _ 

31_ __ _ 32 ___ _ 33 ___ _ 34 ___ _ 35 ___ _ 36 ___ _ 

37 ___ _ 38 ___ _ 

39 ___ _ 40 ___ _ 41_ __ _ 

42 ___ _ 43 ___ _ 

44 ___ _ 45 ___ _ 46 ___ _ 47 ___ _ 

48 ___ _ 49 ___ _ 50 ___ _ 

51_ __ _ 52 ___ _ 

uw 146 uw 136 uw 150 uw 153 uw 154 uw 125 uw 162 uw 163 

uw 112 uw 165 

UW111 

uw 109 uw 197 

SB 1 

v 22 

F 6508-58 

v 20 

F 6508-14 

F 6508-15· 

F 6508-16 

F 6405-37 

F 6405-38 

F 6405-39 

TZ 86 

v 18 

v 16 

v 17 

F 6410-21 

F 6410-22 

v 19 

CQR 382 

CQR 462 

F 6505-49 

F 6505-50 

F 6505-51 

F 6505-53 

F 6505-83 

F 6505-84 

F 6505-91 

v 21 

F 6505-92 

F 6505-103 

F 6505-104 

F 6505-117 

F 6505-118 

F 6505-119 

F 6505-134 

F 6505-135 

F 6505-137 

F 6505-152 

F 6505-153 

F 6511-39 

Geographic 

Cape Flattery, Wash -------------------------

____ do -------------------------------------- ____ do -------------------------------------- Waatch Point -------------------------------- Mukkaw Bay -------------------------------- Point of the Arches --------------------------

____ do --------------------------------------

Cape Alava ----------------------------------

____ do -------------------------------------- ____ do --------------------------------------

____ do -------------------------------------- ____ do -------------------------------------- Destruction Island --------------------------- Blakely Rock -------------------------------- South of Pacific Beach -----~----------------­

Columbia River ------------------------------ Tillamook Head, Ore --------------------------

Netarts Bay --------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Nestucca Bay -------------------------------

____ do -------------------------------------- ____ do -------------------------------------- Depoe Bay ---------------------------------- Newport ------------------------------------ ____ do -------------------------------------- Heceta Head --------------------------------

Umpqua River ------------------------------

____ do -------------------------------------- Coos Head _________________________________ _ Sunset Bay _________________________________ _ 

____ do -------------------------------------- Cape Arago ---------------------------------- ____ do --------------------------------------

____ do -------------------------------------- ____ do -------------------------------------- Cape Blanco --------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do --------------------------------------

South of Cape Blanco -------------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- California-Oregon border ---------------------

Lat 

north 

48°24' 

48°21' 

48°21' 

48°20' 

48°19' 

48°15' 

48°14' 

48°10' 

48°06' 

48°06' 

48°05' 

48°04' 

47°41' 

47°35' 

47°12' 

46°10' 

45°58' 

45°25' 

45°25' 

45°25' 

45°10' 

45°10' 

45°10' 

44 °48' 

44 °40' 

44 °35' 

44°09' 

43°40' 

43°40' 

43°20' 

43°20' 

43°20' 

43°16' 

43°16' 

43°16' 

43°16' 

42°53' 

42°53' 

42°50' 

42°50' 

42°47' 

42°44' 

42°41' 

42°38' 

42°38' 

42°35' 

42°32' 

42°32' 

42°29' 

42°23' 

42°23' 

4r59' 

Long 

west 

124°40' 

124 °45' 

124°32' 

124 °42' 

124 °41' 

124°42' 

124 °43' 

124°45' 

124 °42' 

124°42' 

124°43' 

124°44' 

124 °47' 

122°28' 

124°12' 

124°01' 

123°56' 

124°00' 

124°02' 

124°04' 

124°04' 

124 °01' 

123°59' 

124°04' 

124°04' 

124 °04' 

124°06' 

124°14' 

124°14' 

124°22' 

124°22' 

124 °22' 

124°24' 

124°25' 

124°27' 

124°29' 

124 °35' 

124°34' 

124°37' 

124°33' 

124°37' 

124 °31' 

124°27' 

124°27' 

124°25' 

124°24' 

124°31' 

124°28' 

124°29' 

124°26' 

124°28' 

124 °14' 

Depth 

(metres) 

80 

47 

17 

20 

17 

17 

28 

16 

23 

11 

13 

30 

11 

15 

B 

18 

B 

37 

55 

73 

64 

29 

15 

21 

B 

B 

B 

27 

52 

B 

TP 

TP 

22 

40 

52 

74 

47 

18 

43 

B 

65 

30 

21 

55 

28 

23 

50 

39 

35 

22 

39 

18 
8 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

TABLE 1.-Location and source of Holocene samples from the shelf off the west coast of the United States and Baja California, Mexico, and 16 Pliocene or Pleistocene samples from southern California-Continued 

Sample 

No. 

53 ___ _ 54 ___ _ 

55 ___ _ 56 ___ _ 

57 ___ _ 58 ___ _ 59 ___ _ 

60 ___ _ 6L __ _ 

62 ___ _ 63 ___ _ 64 ___ _ 65 ___ _ 

66 ___ _ 67 ___ _ 

68 ___ _ 69 ___ _ 

70 ___ _ 7L __ _ 72 ___ _ 73 ___ _ 74 ___ _ 75 ___ _ 76 ___ _ 

77 ___ _ 78 ___ _ 79 ___ _ 

80 ___ _ 8L __ _ 82 ___ _ 83 ___ _ 

84 ___ _ 85 ___ _ 86 ___ _ 

87 ___ _ 88 ___ _ 89 ___ _ 90 ___ _ 9L __ _ 

92. ___ _ 93 ___ _ 94 ___ _ 95 ___ _ 

96 ___ _ 97 ___ _ 98 ___ _ 99 ___ _ 

100 ___ _ 

lOL __ _ 102 ___ _ 

103 ___ _ 104 ___ _ 105 ___ _ 106 ___ _ 107 ___ _ 108 ___ _ 109 ___ _ 

110 ___ _ 

11L __ _ 112 ___ _ 113 ___ _ 114 ___ _ 

115 ___ _ 116 ___ _ 117 ___ _ 

118 ___ _ 119 ___ _ 120 ___ _ 

12L __ _ 122 ___ _ 123 ___ _ 124 ___ _ 

Source 

F 6511-40 

F 6511-41 

F 6511-42 

F 6511-43 

v 15 

FP 1 

V5 

V4 

F 7002-26 

ZUM 1 

ZUM 2 

ZUM 3 

V2 

V3 

RE 3 

RE 2 

BHL 1165 

BHL 1166 

BHL 1168 

BHL 1164 

BHL 802 

BHL 804 

BHL 805 

BHL 806 

BHL 782 

BHL 785 

BHL 786 

BHL 800 

BHL 1182 

F 7002-29 

BHL 1191 

BHL 1190 

BHL 640 

BHL 642 

BHL 643 

BHL 644 

BHL 645 

BHL 648 

BHL 651 

BHL 658 

BHL 1420 

BHL 1454 

BHL 1469 

BHL 1473 

BHL 1476 

BHL 1478 

F 7002-55 

V6 

V9 

V8 

M4 

M3 

M5 

M2 

Ml 

ZUM4 

Vl 

z 52 

z 50 

z 51 

z 53 

z 54 

TZ 54 

v 10 

v 11 

usc 16175 

usc 13833 

v 12 

usc 13824 

usc 13826 

v 13 

usc 13825 

Location 

Geographic 

California-Oregon Border ---------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Crescent City, CalH --------------------------

____ do -------------------------------------- Patrick's Point __________________________ ----

Laguna Point -------------------------------- Point Arena --------------------------------- Salt Point -----------------------------------

____ do -------------------------------------- ____ do -------------------------------------- Bodega Head -------------------------------- ____ do -------------------------------------- Horseshoe Cove ------------------------------ Bodega Harbor ------------------------------ Bodega Bay ---------------------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Tomales Point ------------------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Bodega Bay ---------------------------------

____ do -------------------------------------- ____ do -------------------------------------- South of Tomales Point ----------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Point Reyes Beach ---------------------------

Drakes Bay ---------------------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Point Reyes ---------------------------------- Halfmoon Bay -------------------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Point Afi.o Nuevo ----------------------------

Greyrock ------------------------------------ Soquel Cove --------------------------------- Seacliff Beach _________ ----------------------

Monterey Bay -------------------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Partington Point -----------------------------

Point Piedras Blancas ------------------------

Morro Bay ---------------------------------- Estero Bay ---------------------------------- ____ do -------------------------------------- Morro Bay ---------------------------------- ____ do -------------------------------------- Estero Bay ---------------------------------- Avila State Beach ----------------------------

Surf ---------------------------------------- Point Conception _______ - --------------------

_ ___ do -------------------------------------- El Capitan State Park ------------------------ Gaviota ___________ --------------------------

Gato ---------------------------------------- Goleta State Beach ---------------------------

Gato ----------------------------------------

Lat Long Depth 

north west (metres) 

41 °59' 124°16' 24 

41 °59' 124°17' 27 

41 °59' 124°18' 37 

41 °59' 124°20' 43 

41 °44' 124°10' B 

41 °44' 124°10' B 

41 °08' 124°10' IT 

39°30' 123°48' TP 

39°01' 123°43' 37 

38°34' 123°20' 12 

38°34' 123°20' 9 

38°34' 123°20' 9 

38°19' 123°04' TP 

38°19' 123°04' TP 

38°19' 123°04' 6 

38°18' 123°03' IT 

38°18' 123°03' 5 

38°18' 123°02' 5 

38°18' 123°02' 5 

38°17' 123°03' 10 

38°15' 123°00' 20 

38°15' 122°59' 18 

38°15' 122°59' 13 

38°15' 122°58' 11 

38°15' 122°57' IT 

38°14' 122°58' IT 

38°14' 122°58' IT 

38°13' 123°01' 49 

38°11' 122°59' 38 

38°10' 122°59' 35 

38°10' 123°00' 61 

38°09' 122°59' 51 

38°01' 122°56' 13 

38°00' 122°56' 18 

38°00' 122°56' 20 

38°00' 122°56' 22 

38°00' 122°55' 29 

37°59' 122°57' 9 

37° 59' 122°56' 13 

37°59' 122°59' 14 

37°34' 122°35' 39 

37°28' 122°27' 9 

37°30' 122°29' 11 

37°36' 122°30' IT 

37°36' 122°30' IT 

37°36' 122°31' IT 

37°07' 122°21' 36 

37°06' 122°17' B 

36°58' 121 °56' B 

36°57' 121 °53' B 

36°54' 121° 51' 12 

36°53' 12P50' 10 

36°51' 121 °50' 18 

36°50' 121 °49' 11 

36°48' 12P48' 18 

36°12' 121 °44' 11 

35°40' 121 °15' TP 

35°22' 120°51' 5 

35°21' 120°52' 12 

35°21' 120°52' 14 

35°21' 120°51' 5 

35°21' 120°50' IT 

35°21' 120°53' 31 

35°10' 120°43' B 

34°41' 120°36' B 

34°31' 120°33' 37 

34°30' 120°31' 67 

34 °29' 120°01' B 

34°26' 120°15' 117 

34°26' 120°21' 84 

34°25' 119°50' B 

34°25' 120°21' 100 
DISTRIBUTION OF MARINE ORGANISMS 9 

TABLE !.-Location an~ sourc.e of Holocene samples from the shelf off the west coast of the United States and Baja Califorma, Mexwo, and 16 Pliocene or Pleistocene samples from southern California-Continued 

Sample Location 

No. Source Lat Long Depth Geographic north west (metres) 

125 ____ usc 13827 Gato 126 ____ ---------------------------------------- 34 °25' 120°23' 114 usc 13828 ____ do 127 ____ -------------------------------------- 34 °25' 120°23' 88 usc 13830 Government Point 128 ____ --------------------------- 34°25' 120°25' 117 usc 13832 Point Conception 129 ____ ----------------------------- 34°25' 120°29' 148 usc 13821 Capitan 130 ____ ------------------------------------- 34°24' 120°01' 108 CDM 16322 Point Mugu 131_ ___ --------------------------------- 34 °04' 119°03' 33 CDM 16323 ____ do 132 ____ -------------------------------------- 34°03' 119°00' 40 v 14 Malibu Beach ------------------------------- 34 °02' 118°40 B 133 ____ usc 15709 Point Mugu --------------------------------- 34°02' 119°01' 119 134 ____ CDM 16318 Anacapa Island 135 ____ ------------------------------ 34°01' 119°26' 64 CDM 16319 ____ do -------------------------------------- 34 °01' 119°27' 64 136 ____ CDM 16325 Point Dume --------------------------------- 34 °01' 118°51' 37 137 ____ usc 15462 Santa Monica Bay --------------------------- 138 ____ 34 °01' 118°36' 37 usc 15464 ____ do -------------------------------------- 139 ____ 34°01' 118°34' 27 usc 15466 ____ do -------------------------------------- 34 °01' 118°33' 20 140 ____ CDM 16308 Santa Cruz Island ---------------------------- 33°59' 119°32' 22 141_ ___ CDM 16309 ____ do -------------------------------------- 33°59' 119°33' 31 142 ____ usc 15476 Santa Monica Bay --------------------------- 33°59' 118°29' 15 143 ____ usc 15478 ____ do -------------------------------------- 33°59' 118°31' 37 144 ____ usc 15482 ____ do -------------------------------------- 33°59' 118°35' 57 145 ____ CDM 16311 Santa Cruz Island ---------------------------- 33°58' 119°36' 46 146 ____ CDM 16311B ____ do -------------------------------------- 33°58' 119°36' 46 147 ____ CDM 16292 Santa Cruz Island ---------------------------- 33°58' 119°35' 83 148 ____ CDM 16293 ____ do -------------------------------------- 33°58' 119°39' 55 149 ____ CDM 16295 ____ do -------------------------------------- 33°57' 119°40' 55 150 ____ CDM 16297 ____ do -------------------------------------- 33°57' 119° 43' 51 151_ ___ usc 15456 Santa Monica Bay ---------------------------- 33°56' 118°28' 34 152 ____ CDM 16300 Santa Rosa Island ---------------------------- 33°55' 120°00' 26 153 ____ CDM 16298 ____ do -------------------------------------- 33°54' 119°59' 37 154 ____ usc 15440 Santa Monica Bay --------------------------- 33°53' 118°32' 70 155 ____ usc 15443 ____ do -------------------------------------- 33°53' 118°28' 46 156 ____ usc 15424 ____ do -------------------------------------- 33°50' 118°31' 97 157 ____ usc 15552 San Pedro Bay ------------------------------- 33°42' 118°12' 22 158 ____ usc 15068 ____ do -------------------------------------- 33°41' 118°16' 31 159 ____ usc 15131 ____ do ---------------~---------------------- 33°41' 118°12' 24 160 ____ CDM 16338 ____ do -------------------------------------- 33° 41' 118°11' 22 161_ ___ CDM 16346 ____ do -------------------------------------- 33°40' 118°08' 24 162 ____ usc 15064 ____ do -------------------------------------- 33°39' 118°15' 46 163 ____ CDM 16330 ____ do -------------------------------------- 33°38' 118°10' 33 164 ____ usc 15142 ____ do -------------------------------------- 33°38' 118°11' 33 165 ____ CDM 16329 ____ do -------------------------------------- 33°36' 118°11' 35 166 ____ z 41 Balboa -------------------------------------- 33°35' 117°52' 30 167 ____ z 43 _ ___ do -------------------------------------- 33°35' 117°52' 8 168 ____ usc 15155 San Pedro Bay ------------------------------ 33°35' 118°12' 60 169 ____ usc 15158 _ ___ do -------------------------------------- 33°35' 118°07' 62 170 ____ z 48 Balboa -------------------------------------- 33°34' 117°50' 14 171_ ___ z 45 ____ do -------------------------------------- 33°33' 117°49' 8 172 ____ z 47 ____ do -------------------------------------- 33°33' 117°49' 18 173 ____ usc 15166 San Pedro Bay ------------------------------- 33°33' 118°13' 247 174 ____ z 34 Dana Point ---------------------------------- 33°28' 117°43' 12 175 ____ z 35 ____ do -------------------------------------- 33°28' 117°44' 20 176 ____ z 31 ____ do -------------------------------------- 33°27' 117°41' 12 177 ____ z 33 ____ do -------------------------------------- 33°27' 117°43' 14 178 ____ z 37 ____ do -------------------------------------- 33°27' 117°43' 12 179 ____ z 40 ____ do -------------------------------------- 33°27' 117°41' 6 180 ____ CQR 318 Santa Catalina Island ------------------------ 33°27' 118°30' 61 181_ ___ TZ 100 ____ do -------------------------------------- 33°26' '118°29' 6 182 ____ usc 15272 ____ do -------------------------------------- 33°26' 118°23' 247 183 ____ usc 15260 ____ do -------------------------------------- 33°23' 118°20' 64 184 ____ usc 15255 ____ do -------------------------------------- 33°21' 118°18' 91 185 ____ z 30 Oceanside --------------------------------- 33°12' 117°23' 7 

186 ____ z 29 ____ do -------------------------------------- 33°12' 117°23' 8 

187 ____ z 20 ____ do -------------------------------------- 33°11' 117°24' 14 

188 ____ z 21 ____ do -------------------------------------- 33°11' 117°24' 16 

189 ____ z 27 ____ do -------------------------------------- 33°11' 117°23' 6 

190 ____ z 22 ____ do -------------------------------------- 33°10' 117°24' 18 

191_ ___ z 24 ____ do -------------------------------------- 33°10' 117°23' 14 

192 ____ CDM 15800 ____ do -------------------------------------- 33°09' 117°17' 64 

193 ____ v 7 Pacific Beach -------------------------------- 32°48' 117°16' B 

194 ____ z 10 ____ do -------------------------------------- 32°45' 117°16' 14 

195 ____ z 7 San Diego ----------------------------------- 32° 41' 117°13' 12 

196 ____ z 6 ____ do -------------------------------------- 32°40' 117°13' 5 
10 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

TABLE !.-Location an~ sourc~ of Holocene samples from the shelf off the west coast of the United States and Baja Calitorma, Mextco, and 16 Pliocene or Pleistocene samples from southern California-Continued 

Sample 

No. 

197 ___ _ 198 ___ _ 199 ___ _ 

200 ___ _ 201_ __ _ 202 ___ _ 203 ___ _ 

204 ___ _ 205 ___ _ 206 ___ _ 

207 ___ _ 

208 ___ _ 209 ___ _ 210 ___ _ 

211_ __ _ 212 ___ _ 213 ___ _ 214 ___ _ 

215 ___ _ 216 ___ _ 217 ___ _ 218 ___ _ 219 ___ _ 

220 ___ _ 221_ __ _ 222 ___ _ 

223 ___ _ 224 ___ _ 22.5 ___ _ 

226 ___ _ 227 ___ _ 

228 ___ _ 

229 ___ _ 230 ___ _ 

231_ __ _ 232 ___ _ 233 ___ _ 234 ___ _ 235 ___ _ 236 ___ _ 237 ___ _ 

238 ___ _ 239 ___ _ 240 ___ _ 

241_ __ _ 242 ___ _ 243 ___ _ 244 ___ _ 

245 ___ _ 246 ___ _ 247 ___ _ 

248 ___ _ 249 ___ _ 250 ___ _ 

251_ __ _ 252 ___ _ 

253 ___ _ 254 ___ _ 

255 ___ _ 

Mf2180 

Mf2179 

Mf2178 

Mf2177 

Mf2176 

Mf2175 

Mf2174 

Source 

Z2 

Z3 

Z4 

Z1 

TZ 97 

TZ 98 

TZ 99A, B 

TZ 117 

TZ 118 

TZ 119 

TZ 120 

TZ 121 

TZ 122 

TZ 113 

TZ 114 

TZ 115 

TZ 116 

TZ 18 

TZ 19 

TZ 20 

TZ 21 

TZ 22 

CQR 12 

TZ 23 

TZ 24 

TZ 2 

TZ 4 

TZ 26 

TZ 48-Z 

TZ 48-7 

TZ 25 

TZ 45 

TZ 46 

TZ 43 

TZ 44 

TZ 47 

TZ 41 

TZ 42 

TZ 40A 

TZ 40B 

TZ 27 

TZ 28 

TZ 38A 

TZ 38B 

TZ 39 

TZ 37 

TZ 30 

TZ 29 

TZ 31 

EZ 4 

EZ 3 

JH 3 

JH 2 

TZ 35 

TZ 32 

TZ 33 

c 376 

c 327 

c 300 

Location 

Geographic 

San Diego ----------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- COironados Island, B.C ------------------------

____ do -------------------------------------- ____ do -------------------------------------- Bahia de Todo.s Santos -----------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do --------------------------------------

____ do -------------------------------------- ____ do -------------------------------------- Punta Banda -------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Isla San Martin ------------------------------

____ do -------------------------------------- Isla San Geronimo ----------------------------

____ do -------------------------------------- ____ do -------------------------------------- Islas San Benitos ----------------------------

____ do -------------------------------------- ____ do -------------------------------------- Bahia Vizcaino ______________________ ---- ___ -

____ do -------------------------------------- Punta Eugenia ________________ --- ________ - __ _ 

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Puerto S. Bartolome -------------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Bahia Asuncion ____ -- ___ ---------------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Bahia San Hipolito --------------------------

____ do -------------------------------------- Punta Abreojos ___________ -- _----------------

____ do -------------------------------------- ____ do -------------------------------------- ____ do -------------------------------------- Punta Huches __________ ---------------------

____ do --------------------------------------

____ do -------------------------------------- Punta Pescadores -- ___ -----------------------

Cabo Pulmo --------------------------------- Los Frailes ---------------------------------- _ ___ do -------------------------------------- Cabo San Lucas ------------------------------ ____ do -------------------------------------- _ ___ do -------------------------------------- West Coast Mexico ---------------------------

_ ___ do -------------------------------------- ____ do --------------------------------------

Santa Maria district 

Careaga Sandstone _ --------------------------

____ do -------------------------------------- Foxen Mudstone ----------------------------- ____ do --------------------------------------

Santa Barbara 

Santa Barbara Formation ---------------------

____ do ------------------------------------ ____ do --------------------------------------

Lat Long Depth 

north west {metres) 

32°39' 117°11' 12 

32°39' 117°10' 12 

32°39' 117°09' 8 

32°38' 117°13' 12 

32°25' 117°15' 11 

32°25' 117°15' 18 

32°24' 117°14' 18 

31° 45' 116°41' 31 

31 °44' 116°40' 24 

31 °44' 116° 41' 18 

31° 44' 116°40' 13 

31 °43' 116°40' 9 

31 °43' 116°40' 5 

31 °42' 116° 41' 32 

31 °42' 116°41' 24 

31 °42' 116° 41' 15 

31° 42' 116°41' 6 

30°29' 116°06' 9 

30°28' 116°06' 1 

29° 47' 115° 47' 11 

29°47' 115°47' 8 

29°47' 115°47' 8 

28°18' 115°34' 165 

28°18' 115°34' 17 

28°18' 115°34' 6 

28°08' 114 °17' ?48 

28°06' 114°15' ?48 

27°52' 115°02' 9 

27°52' 115°02' 8 

27°52' 115°02' 8 

27°51' 114°51' 35 

27°41' 114°52' 6 

27°41' 114°53' 1 

27°40' 114 °53' 9 

27°40' 114°53' 9 

27°39' 114 °52' 11 

27°08' 114°17' 9 

27°08' 114°17' 6 

27°07' 114°17' 9 

27°07' 114 °17' 9 

26°58' 113°58' 9 

26°58' 114°00' 6 

26°42' 113°39' 6 

26°42' 113'!39' 6 

26°42' 113°38' 10 

26°41' 113°39' 16 

24 °46' 112°16' 17 

24°45' 112°16' 6 

24°45' 112·0

15' 20 

23°45' 109°44' 3 

23°27' 109°25' 2 

23°24' 109°25' 29 

23°24' 109°25' 23 

22°53' 109°53' 10 

22°52' 109°53' 24 

22°52' 109°53' 7 

22°45' 105°59' 15 

22°10' 106°07' 58 

21 °43' 105° 40' 31 

34°54' 120°19' 

34 ° 52' 120°31' 

34°52' 120°31' 

34°52' 120°31' 

34°25' 119° 41' 

34°25' 119°41' 

34°25' 119°41' 
MARINE CLIMATE 11 

TABLE 1.-Location an~ sourc.e of Holocene samples from the shelf off the west coast of the United States and Baja Califo'rnta, Mextco, and 16 Pliocene or Pleistocene samples from southm"n Califo1·nia-Continued 

Sample Location 

No. Source Geographic Lat 

north 

Long 

west 

Depth 

(metres) 

San Pedro 

Mf2173 

Mf2172 Palos Verdes Sand --------------------------- Timms Point Silt Member of 

33°44' 

33°44' 

118°17' 

118°17' 

San Pedro Formation. 

Mf2171 

Mf2170 ____ do -------------------------------------- 33°44' 

33°44' 

118°17' 

Lomita Marl Member of San Pedro 118°17' 

Formation. 

Mf2169 

Mf2168 ____ do -------------------------------------- ____ do --------------------------------------

33°44' 

33°44' 

118°17' 

118°17' 

Pacific Beach 

Mf2167 

Mf2166 

Mf2165 

San Diego Formation ------------------------ 32°48' 

32°48' 

32°48' 

117°16' 

117°16' 

117°16' ____ do -------------------------------------- ____ do --------------------------------------

organisms are developed on the continental shelves, 

and these patterns are recognized as faunal 

provinCies. 

Provinc.es are unique. Climatic changes, faunal 

migrations, and evolutionary events militate a.gains.t 

duplication of successive provinces through time. 

Even if only the climate is altered, species will be 

found in new associations and thus constitute different provinces. Hazel (1970) showed that modern 

amphiatlantic ostracode species exhibit different 

latitudinal ranges and form different species associations because the marine climates differ on opposite 

sides of the same ocean basin. 

Six provinces based on mollu~~an distributions 

(J. W. Valentine, 1966, 1973) can be identified on 

the west coast of North America. These a.re: the 

Bering province extending from Point Barrow to 

the Aleutian Island arc area ; the Aleutian province 

south to Dixon Entrance; the Oregonian extending 

to Point Conception ; the Californian south to Punta 

Eugenia-Cedros I·sland; the Surian which reaches 

Cabo San Lucas; and finally the tropical Pana.manian province which extends southward. Prior to the 

present study, no ostracode provinces have been delineated along this coast, although they have been 

established off the east coast of North America 

(Hazel, 1970; P. C. Valentine, 1971). 

MARINE CLIMATE OFF THE WEST COAST OF THE 

UNITED STATES AND BAJA CALIFORNIA, MEXICO 

A marine climate is expressed primarily in temperature, andJ to a far lesser degree, salinity configurations which result from the interactions of many 

factors. Latitudinal position (especially along northsouth coastlines) , worldwide s1easonal climatic patte·rns, and major oceanic current patterns impart a 

fundamental character to the marine climate. Other 

factors such as s:easonal wind-driven currents, upwelling, and current interactions produce local temperature anomalies and steep te.mperature gradients 

which form thermal barriers that restrict the distributions of many species. 

The pattern of the earth' atmosphe·ric winds is responsible for the configuration of major oce,anic current system·s. The North Pacific Ocean exhibits an 

anticyclonic current pattern, which results in the 

transport of water from north to south along the 

coasts· of the ewstern Pacific, westward in equatorial 

latitudes toward the Asian mainland, and then 

northward along the coast of Japan, and finally eastward to North America. The waters of this North 

Pacific gyre are affected by mixing of waters from 

neighboring regions which, along with the effects of 

solar radiation, de1termine the overall temperature 

and salinity of the system. 

The west coast of North America, from British 

Columbia to the southern tip of Baja California, is 

bathed by cold northern waters of the California 

Current, the south-southeast-flowing arm of the 

No,rth Paeific gyre, whieh is the major influence on 

the marine clima~te along the coasts of the the United 

States and Baja California. Reid and others (1958) 

have discussed the characte.ristics of this current 

system, and the following summary is based mainly 

on their report. 

The California Current is a permanent stream orf 

cold water about 560 km wide and 300 m de1ep which 

moves southeastward at about 0.5 knot. It transports approximately one-tenrth the volume of water 

e·arried by the Gulf S.trea.m of the western Atlantic 

Ocean. Near Gabo San Lucas, Baja California, the 

current turns west to become part of the weJstward-
12 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

flowing North Equa.torial Current. The waters of the 

current system are a mixture of four water masses. 

Subarctic water enters fro-m the north (relatively 

low temperature and salinity and high phosphate and 

dissolved-oxygen content) and maintains its character throughout the length of the current. Central 

North Pacific water (relative,ly higher temper-ature 

and salinity and lower nutrient content) lies to the 

west of the Subarctic Water Ma.ss and mixes with it 

at the surface. Equatorial Pacific water (still higher 

temperature, salinity, and phosphate content but 

low dissolved-oxygen content) flows northward in a 

countercurrent below 200 m along the Baja California and California coasts to about Cape Mendocino. 

Finally, upwelled water, which is colder, more saline, 

and higher in nutrients than the surrounding water 

masses, originates from Subarctic and Equatorial 

Pacific water at depth. Although the California Current is the dominant oceanic flow off these coasts, a 

complex system of transient seasonal currents and 

eddies occurs between the main current and the 

coast. They are the result of the interaction of seasonal winds, the main current, the deep countercurrent, and upwelled waters. 

Winds influencing the system are principally from 

the north and northwest, and they are strongest 

fro-m spring to fall. During the winter months these 

winds weaken or revers1e direction, which results in 

the surfacing of the northwest-flowing countercurrent (often caHed the Davidson Current) along Baja 

California to north of Point Conception. The Southern California Countercurrent is a permanent but 

weak cyclonic eddy located south of Point Conception in the Channel Island region. The eas.tern arm 

of this eddy flows slowly north adj-acent to the coastline and becom·es warmer than the western arm 

which is expo-sed to the California Current. In the 

late fall and early winter, when the deep countercurrent surfaces, warm southern W'ater augments this 

gyre and northward surface flow takes plac.e around 

Point Conception where at othe1r times of the year 

the flow is southward. 

Interaction of northerly winds, the Coriolis effect, 

and the configuration of the coasts and the sea bottom causes movem:ent of the surface waters away 

from the shore and establishes areas of upwelling 

along the coast from Cape Mendocino south to Cabo 

San Lazaro. Upwelling occurs chiefly in the spring 

and summe'r when the northerly winds are strongest. These winds increase in strength along the 

coasts from south to north as the year progresses. 

Consequently, upwelling is most pronounced off Baja 

California in April and May, off southern and central California in May and June, off northern California in June ·and July, and off Oregon in August 

and September. Upwelling is common to some extent 

all along these coasts. It is, however, intensified in 

some regions (fig. 5), especially s.outh of coastal 

promontories. These regions include: Cape Mendocino ·and Cape Blanco ; off the central California 

coast south of Monterey Bay; and off the southern 

California coast north of Santa Monica Bay. To the 

south the area from north of San Diego to south of 

Punt:a Baja is characterized by upwelling, as is the 

coast s.outh of Punta Eugenia and south of Cabo 

San Lazaro. 

The upwelling of cold, nutrient-rich water is, in 

particular, a phenom·enon which has profound effects 

on the marine environment along these coasts. It is 

an important mechanism for the recycling of nutrients from deep oceanic wate.rs into the shallow marine ecosystem, and its effect on the marine climate 

influences the distribution of organisms along the 

shelf. The minimum and maximum water temperatures off the west coasts of the United States and 

Baja California are illustrated in figures 6 and 7. 

From Cabo San Lucas north to San Francisco the 

maps are based on tempei'ature determinations at 

-10 m (Lynn, 1967) ; from San Francisco north to 

Gape Flattery they are based on surface temperatures (Robinson, 1957). Areas of intense upwelling 

are easily discrernible on these maps. 

In the region from Punta Baja to Cape Blanco, 

upwelling has the effect of reducing the annual temperature range to 3° to 5o C and retarding the seasonal warming produced by solar radiation. South of 

Punta Baja, the contras.t between pronounced spring 

upwelling and summer warming caused by both intense radiation and warm, northward-flowing surface waters produces annual temperature ranges 

great'e·r than 10° C. Upwelling, rather than current 

interactions (such as those in existence off the east 

coast of North America) , causes the most pronounced te,mperature gradients along this coast. 

HOLOCENE OSTRACODE DISTRIBUTION PATTERNS 

Although Swain (1966) and Swain and Gilby 

(1974) noted an ostracode faunal discontinuity at 

Point Conception, the present s.tudy is the first attempt to define faunal provinces in the eastern 

Pacific on the basis of ostracode distributions. From 

biogeographic studies on this and other coasts, it is 

apparent that provincial s~chemes based on different 

invertebrate and plant groups (Mollusca, Crustacea, 
OREGON 

0 

I 

0 

CALIFORNIAN 

I 

SUR IAN 

300 MILES I 

300 KILOMETRES 

DISTRIBUTION PATTERNS 

30° 

25° 

22°45' --+----------+ 

PANAMANIAN 

~---~~-------------~----------------~----------------._ _____________ ~20° 

13 

FIGURE 5.-0stracode faunal provinces and the distribution of areas of intense upwelling (stippled pattern) along the Pacific 

coasts of the United States and Baja California (after Manar, 1953, and Lynn, 1967). 
14 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

PACIFI~ 

OCEAN 

---..,.,......1 .s"-

::: .••••... =:.•.=·· 

< 

... .., .... 

· .. :•··,···. . . . . 

·:.:· 

....... ·.=-=: 

/ . . : .. ·· ... 

. ..· 

. . · ....... "'. ::• 

(l;c1pe Biarc~ ·•= • 

(:: .· .. · •• (-= ····:::.····· ..... \: ·. 

. . · .... 

. .. · ..... . ... . · ..... r-; .. ' ... ·· 

9 

6 I 

' 

I 

' '~ 

I 

I·: : .· 

ls pe :r IUUI,.;IriU > . 

..... .. ..... 

.;;.·.·. ....... 

-

...... 

. · ....... 

< 

······· 

.. .· ....... . 

,,: ... . 

..... 

. .:·· .. 

. · ... 

. ..... . 

.... 

. < > •. 

. ····•·· . . ...... 

······ ··.••·•·. 

.... ····· 

. : ..... 

•········· 

((··········. 

....... 

.. .......... · . 

····· .· ...... 

·················· .. • .. .• • . ..... >> : · .. 

. · ... · ..... . ·. : ..... : .. :. 

. ..... 

. ······.; .. 

·····•·· .... · ...... < . •••··· •. · . .. ....... . ..... 

. :.:.:=:· 

••• 

FIGURE 6.-Sea-temperature map (in degrees Celsius) for the shelf off the Pacific coasts of the United States and Baja California. Yearly minimum temperatures at -10 m from San Francisco south are after Lynn, 1967, and yearly minimum 

surface temperatures :£rom San Francisco north are after Robinson, 1957. 
130° 

' ' 

DISTRIBUTION PATTERNS 

0 300 MILES 

~~--~~~--~,~~----~' 

0 300 KILOMETRES 

15 

45° 

FIGURE 7.-Sea-temperature map (in degrees Celsius) for the shelf off the Pacific coasts of the United States and Baja California. Yearly maximum temperatures at -10 m from San Francisco, south are after Lynn, 1967, and ye....rly maximum 

surface temperatures :firom San Francisco north are after Robinson, 1957. 
16 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

Ostracoda, Foraminifera, and intertidal flora and 

fauna) are fairly coincident. (See references in J. 

W. Valentine, 1966; in Hazel, 1970; and in Lankford 

and Phleger, 1973.) This result lends weight to the 

hypothesis (J. W. Valentine, 1968, 1973) that 

provinces are composed of communities, the aspects 

(structure, composition, function) of which are 

characteristic of the provinces in which they occur. 

As expected, the ostracode provinces in the area under investigation mimic those based on the Mollusca. 

Subprovinces exist, however, which are new or 

which deviate from those of the Mollusca. 

In order to delineate the provinces, a cluster analysis of similarity coefficients was made. I conside~r this 

method to be the most expeditious and efficient 

means o.f comparing the faunal compositions of shelf 

areas. This tool has been utilized in previous studies 

(J. W. Valentine, 1966; J. W. Valentine and Peddicord, 1967; P. C. Valentine, 1971). The samples for 

this investigation were assembled from various 

sourees and are not evenly dis,tributed over the shelf 

area. The study, however, is based on the latitudinal 

ranges of ostracode species, and these ranges are 

adequately delineated by the samples analyzed. It is 

considered that samples composed of assemblages 

from consecutive latitudinal segments of shelf along 

the coast form a better basis for comparison than 

samples distributed nonuniformly over the shelf. If 

it is reasonable to conclude that species occurring at 

points along the shelf also occur on the shelf betw·een 

those points, then all species occurring in or ranging 

into or through each 15-minute (latitude) shelf segment (sample) can be considered to be a member of 

that sample (figs. 1-4; see table 2 for latitudinal 

ranges of 15-minute samples). Choice o.f 15-minute 

samples was made to achieve a balance between sample size and sampling detail; the sample matrix was 

limited to manageable proportions, and samples remained small enough so that s~ample groups that 

might segregate over short geographic distances on 

the shelf would be detected. 

A Q-mode cluster analysis (defining groups of 

samples based on the similarity of their species composition) was therefore based on a comparison of 

the faunal content o.f 110 15-minute samples. Degree 

of similarity between samples was calculated using 

the Otsuka similarity coefficient (C/yNtNz) and 

presence-absence data, where C =number of species 

in common between two samples containing N 1 and 

N 2 species. The Otsuka coefficient was chosen because 

it gives results which neither emphasize difference 

(as does the Jaccard coefficient) nor similarity (as 

TABLE 2.-Latitudinal ranges of 15-minute samples along the 

the west coast of the United States and Baja California, 

Mexico 

Sample 

001 

002 

003 

004 

005 

006 

007 

Latitudinal range (north) 

Panamanian faunal province 

21° 30' -21° 45' 

45'-22°00' 

22°00'- 15' 

15'- 30' 

30'- 45' 

southern Surian faunal province 

008, 109 

009, 110 

010 

22°45'-23°00' 

23°00'- 15' 

15'- 30' 

30'- 45' 

45'-24°00' 

011 

012 

013 

014 

015 

016 

017 

018 

019 

020 

021 

022 

023 

024 

025 

026 

027 

028 

029 

030 

031 

032 

033 

034 

035 

036 

037 

038 

039 

040 

041 

042 

043 

044 

045 

046 

047 

048 

049 

050 

051 

052 

053 

054 

055 

056 

057 

058 

24°00'- 15' 

15'- 30' 

30'- 45' 

northern Surian faunal province 

24 ° 45' -25°00' 

25°00'- 15' 

15'- 30' 

30'- 45' 

45'-26°00' 

26°00'- 15' 

15'- 30' 

30'- 45' 

45'-27°00' 

27°00'- 15' 

15'- 30' 

30'- 45' 

45'-28°00' 

28°00'- 15' 

southern Californian faunal province 

28°15'-28°30' 

30'- 45' 

45'-29°00' 

29°00'- 15' 

15'- 30' 

30'- 45' 

45'-30°00' 

30°00'- 15' 

15'- 30' 

30'- 45' 

45'-31 °00' 

3roo·- 15' 

15'- 30' 

30'- 45' 

45'-32°00' 

32°00'- 15' 

15'- 30' 

30'- 45' 

45'-33°00' 

33°00'- 15' 

15'- 30' 

30'- 45' 

45'-34°00' 

northern Californian faunal province 

34°00'-34°15' 

15'- 30' 

30'- 45' 

45'-35°00' 

35°00'- 15' 

15'- 30' 

southern Oregonian faunal province 

35 ° 30' -35 ° 45' 

45'-36°00' 
DISTRIBUTION PATTERNS 17 

TABLE 2.-Latitudinal ranges of 15-minute samples along 

the west coast of the United States and Baja California, 

Mexico-Continued 

Sample 

059 

060 

061 

062 

063 

064 

065 

066 

067 

068 

Latitudinal range (north) 

southern Oregonian faunal province 

36°00'- 15 

15'- 30' 

30'- 45' 

45'-37°00' 

37°00'- 15' 

15'- 30' 

30'- 45' 

45'-38°00' 

38°00'- 15' 

15'- 30' 

northern Oregonian faunal province 

069 

070 

071 

072 

073 

074 

075 

076 

077 

078 

079 

080 

081 

082 

083 

084 

085 

086 

087 

088 

089 

090 

091 

092 

093 

094 

095 

096 

097 

098 

099 

100 

101 

102 

103 

104 

105 

106 

107 

108 

38°30'-38° 45' 

45'-39°00' 

39°00'- 15' 

15'- 30' 

30'- 45' 

45'-40°00' 

40°00'- 15' 

15'- 30' 

30'- 45' 

45'-41 °00' 

41°00'- 15' 

15'- 30' 

30'- 45' 

45'-42°00' 

42°00'- 15' 

15'- 30' 

30'- 45' 

45'-43°00' 

43°00'- 15' 

15'- 30' 

30'- 45' 

45'-44°00' 

44°00'- 15' 

15'- 30' 

30'- 45' 

45'-45°00' 

45°00'- 15' 

15'- 30' 

30'- 45' 

45'-46°00 

46°00'- 15' 

15'- 30' 

30'- 45' 

45'-47°00' 

47°00'- 15' 

15'- 30' 

30'- 45' 

45'-48°00' 

48°00'- 15' 

15'- 30' 

does the Simpson coefficient) between the samples 

being compared. (See Cheetham and Hazel, 1969, for 

a resume of binary similarity coefficients.) The samples we~re associated and ordered in a dendrogram 

using the unweighted pair-group method of clustering (Sokal and Michener, 1958). This procedure allows all samples to have equal weight when being 

comp~ared to another sample or samples (in an already formed cluster) . Since all samples in this 

study represent an ·equal geographic range (except 

where the coastline deviates from its approximate 

north-south trend), each sample should be considered to be of ~equal importance in determining sample 

clusters (ultimately faunal provinces). The matrix 

used was 192 species by 110 15-minute samples. 

(See table 3 for alphabetical list of ostracode species 

included in cluster analyses.) 

TABLE 3.-Alphabetical list of Holocene and fossil ostracode 

species included in cluster analyses 

No. 

150 

151 

094 

093 

126 

001 

091 

015F 

152 

101 

120 

103 

118 

095 

097 

099 

154 

098 

116 

114 

053 

002 

007 

004 

006 

009 

010 

056 

113 

108 

008 

110 

112 

016F 

024F 

104 

155 

102 

174 

171 

078 

100F 

096 

092F 

178 

040F 

069 

100 

017 

015 

020 

023 

121 

022 

156 

025 

027 

181 

190 

177 

191 

021 

157 

041 

075 

087 

158 

029 

042F 

092 

035 

037 

039 

138 

[F=species occurs only in fossil deposits] 

Species 

Ambostracon californicum (Hazel, 

1962) ------------------------------ A. costatum Hazel, 1962 -------------- A. diegoensis (LeRov, 1943a) --------- A. glaucum {Skogsberg, 1928) 

A. microreticulatum {LeRoy, 1943a) ---

A. sp. A ----------------------------- A. sp. B ----------------------------- A. SD. c ------------------------------ A. sp. D ----------------------------- A. sp. E ----------------------------- A. sp. F ----------------------------- A. sp. G -----------------------------

A. sp. I ------------------------------ A. sp. J ----------------------------- A. sp. K ------------------------------

A. sp. L ----------------------------- A. sp. M -----------------------------

A. sp. N -----------------------------

A. sp. 0 ----------------------------- A. sp. P ---------------------------- A. sp. Q ------------------------------ Aurila lincolnensis (LeRoy, 1943a) --- A. montereyensis {Skogsberg, 1928) ---

A. sp. A ---------------------------- A. sp. B -----------------------------

A. sp. C -----------------------------

A. sp. D ----------------------------- "A uri/a" californica Benson and 

Kaesler, 1963 ------------------------

"A." driveri (LeRoy, 1943a) ---------- "A." schumannensis (LeRoy, 1943a) ---

"A." sp. C ---------------------------

"A." sp. D --------------------------- "A." sp. E ---------------------------

"A." sp. G ---------------------------

"A." sp. H --------------------------- Basslerites delreyensis LeRoy, 1943a ---

B. thlipsurotdea Swain, 1967 ----------

B. sp. B ------------------------------ B. sp. C ----------------------------- "Bradleya" pennata (LeRoy, 1943a) __ _ 

"B." simiensis (LeRoy 1943a, b) ------

Buntonia sp. A -----------------------

B. sp. B ----------------------------- B. sp. C ------------------------------ Bythoceratina sp. A ___ ---------------

Bythocythere sp. A ------------------- CatweUa semttranslucens (Crouch, 

1949) ------------------------------

C. unitaria Swain, 1967 ----------------

C. sp. A ---------------------------- C. sp. B ---------------------------- Caudites fragilis LeRoy, 1943a C. pl•rzi (McKenzie and Swam, 1967) __ 

C. sp. A ----------------------------- C. sp. B ------------------------------

C. sp. C ----------------------------- C. sp. D ----------------------------- C. sp. E ----------------------------- C. sp. F ----------------------------- C. sp. G ------------------------------

C. sp. H -----------------------------

C. sp. I ------------------------------ C. sp. J ------------------------------ C. sp. K ----------------------------- C. sp. L ----------------------------- C. sp. M ----------------------------- Coquimba pichelinguensis (Swain, 

1967) ------------------------------

c. schenclci {LeRoy, 1943a) ----------

C. sp. A ------------------------------

C. sp. B ----------------------------- Costa? sanfelipensis Swain, 1967 ------ Cythere maia {Benson, 1959) ---------

C. sp. A ----------------------------- C. sp. B ------------------------------ Cytherella banda Benson, 1959 --------

Occur- Cluster renee analyses 

Holocene 

and Holo- Fos- Holo- fos- cene sil cene sil 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X. 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 
18 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

TABLE 3.-Alphabetical list of Holocene and fossil ostracode 

species included in cluste'i· analyses-Continued 

No. 

140 

136 

043 

105 

044 

187 

046 

133 

129 

048 

127 

106 

115 

161 

050 

105F 

164 

011 

013 

012 

122 

162 

123 

186 

131 

163 

125 

124 

165 

106F 

054 

055 

057 

059 

065 

060 

063 

062 

064 

066 

067 

068 

070 

132 

071 

073 

074 

166 

072 

005 

140F 

045 

003 

036 

038 

1!:S4 

185 

188 

155F 

149 

077 

164F 

081 

0!:!2 

079 

083 

085 

084 

167 

169 

170 

168 

086 

080 

058 

174F 

088 

090 

089 

178F 

128 

172 

188F 

193F 

160 

194F 

130 

134 

195F 

Species 

C. sp. A ----------------------------- Cytherelloidea californica LeRoy, 1943a_ 

C. sp. A ----------------------------- C. sp. B ----------------------------- C. sp. C ----------------------------- "Cytheretta" corrugata (LeRoy, 1943a) -

"C." sp. A --------------------------- "C." sp. B ----------------------------

"C." sp. C ---------------------------- Cytheromorpha sp. A ----------------- C. sp. B ----------------------------- Cytheropteron dobladoensis Swain, 1967. 

C. johnsonoides (Swain, 1967) ------- C. newportense Crouch, 1949 ----------

C. sp. A ----------------------------- C. sp. B ----------------------------- Eucytherura sp. A ------------------- Hemicythere sp. A --------------------

H. sp. B -----------------------------

H.? sp. C ---------------------------- "Hemicythere" californiensis LeRoy, 1943a ______________________________ _ 

"H." hispida LeRoy, 1943a ------------

"H." sp. A --------------------------

"H." sp. B ---------------------------

"H." sp. C ---------------------------- "H." sp. D ---------------------------

"H." sp. E --------------------------- "H." sp. F ----------------------------

"H." sp. G ----------------------------

"H." sp. H --------------------------- Hemicytherura sp. A -----------------

H. sp. B ----------------------------- H. sp. C ----------------------------- H. sp. D ---------------------------- H. sp. E ------------------------------

Jl, sp. F ----------------------------- H. sp. G -----------------------------

H. sp. H ----------------------------- H. sp. I ------------------------------ H. sp. J ----------------------------- H. sp. K ----------------------------- H. sp. L ----------------------------- Hermamtes kewi (LeRoy, 1943a) -----

H. sp. A ----------------------------- H. sp. B -----------------------------

JI, sp. C ----------------------------- H. sp. D ----------------------------- H. sp. E ----------------------------- H. sp. F ------------------------------

H. sp. G -----------------------------

H. sp. H ----------------------------- Kangarma aff. K. quetltta CoryeJl 

and Fields, 1937 ---------------------

K. sp. A -----------------------------

K. sp. B -----------------------------

K. sp. C ----------------------------- K. sp. D ----------------------------- K. sp. E ----------------------------- K. sp. F ----------------------------- K. sp. G -----------------------------

~Ka~ga~n~;-;;.--;._-==================== Krithe sp. A ------------------------- Loxoconcha helenae Crouch, 1949 ------

L. lentwulata LeRoy, 1943a -----------

£. sp. A ----------------------------- £. sp. B ------------------------------ £. sp. C -----------------------------

£. sp. D ------------------------------ £. sp. E ----------------------------- £. sp. F ----------------------------- "Loxoconcha" emaciata Swain, 1967 __ _ 

Loxocorniculum sculptoides, Swain, 

1967 -------------------------------

L. sp. A ------------------------------ £. sp. B ----------------------------- Munseyella pedroensis Triebel, 1957 ----

M. similis? Triebel, 1957 -------------- M. sp. A ------------------------------

M. sp. B ----------------------------- M. sp. C ----------------------------- M. sp. D ----------------------------- N eocaudites ? henryhowei (McKenzie 

and Swain, 1967) ------------------- New genus A sp. A ------------------ New genus B sp. A ------------------ New genus C sp. A ------------------- New genus D sp. A ------------------ New genus E sp. A ------------------ New genus F sp. A ------------------ Orionina pseudovaughni Swain, 1967 __ _ 

Paijenborchella sp. A ------------------

Occur- Cluster renee analyses 

Holocene 

and Holo- Fos- Holo- fos- cene sil cene sil 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

)( 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

;< 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

TABLE 3.-Alphabetical list of Holocene and fossil ostracode 

species included in cluster analyses-Continued 

No. 

117 

119 

135 

137 

052 

139 

141 

146 

143 

142 

144 

145 

173 

175 

176 

061 

148 

147 

189 

196F 

049 

179 

051 

047 

180 

159 

076 

033 

192 

016 

018 

019 

024 

153 

183 

026 

030 

031 

028 

107 

109 

Ill 

182 

032 

040 

042 

014 

034 

Species 

"Paijenborchella" sp. A ---------------

"P." sp. B ----------------------------

Palaciosa sp. A ---------------------- P. sp. B ------------------------------

P. sp. C ----------------------------- P. sp. D ----------------------------- Palmenella californica Triebel, 1957 --- Paracytheridea granti LeRoy, 1943a --

P. sp. A ----------------------------- P. sp. B ----------------------------- P. sp. C -----------------------------

P. sp. D -----------------------------

P. sp. E -----------------------------

P. sp. F ----------------------------- P. sp. G ----------------------------- Pcctocythere clavata (Triebel, 1957) ---

P. tomalensis Watling, 1970) ---------

P. sp. A ----------------------------- P. sp. B ----------------------------- P. sp. D ----------------------------- Pellucistoma bensoni McKenzie and 

and Swain, 1967 -------------------- P. scrippsi Benson, 1959 --------------

P. sp. A ----------------------------- P. sp. B ------------------------------ Perissocytheridea pedroensis (LeRoy, 1943a) _________ -- _________________ _ 

Pontocythere sp. A ------------------- P. sp. B ----------------------------- P. sp. C ----------------------------- P. sp. D ----------------------------- Pterygocythereis? sp. A -------------- Pulmilocytheridea pseudoguardensis McKenzie and Swain, 1967 ----------

Puriana pacifica Benson, 1959 ---------

P. sp. A -----------------------------

P. sp. B ----------------------------- Radimella convergens (Swain, 1967) __ 

R. palosensis (LeRoy, 1943a) ---------

R. sp. A ----------------------------- R. sp. B ------------------------------ "Radirnella" aurita (:::>kogsbe1·g, 1928) __ 

"R." jollaensis (LeRoy, 1943a) -------- "R." pacifica (Skogsberg, 1928) ______ _ 

"R." sp. A ---------------------------

"R." sp. B ---------------------------- Sahnia sp. A ------------------------- "Trachyleberis" sp. A -----------------

"T." sp. B ---------------------------- Triebelina reticulopunctata Benson, 

1959 -------------------------------

T. sp. A -----------------------------

Occur- Cluster renee analyses 

Holocene 

and Holo- Fos- Holo- fos- cene sil cene sil 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

New information has made it necessary to change 

the names of several of the species treated in this 

>Study. The new species designations !a,re indicated 

below, and the reader may make thes.e changes in 

tables 3 and 4 and in the plate explanations. 

037 Cythere s.p. A= C. alveolivalva Smith, 1952 

046 "Cytheretta" sp. A=" C." minutipunctata Swain 

and Gilby, 197 4 

105 Cytherelloidea sp. B =C. paratewarii Swain and 

Gilby, 1974 

062 Hemicytherura sp. H=H. santosensis Swain 

and Gilby, 1974 

090 Munseyella sp. B =M. parkerae (Swain and Gilby, 1974) 

105 Cytherelloidea sp. B =C. paratewarii Swain and 

Gilby, 1974 

117 "Paij enborchella" sp. A= Acuminocythere crescentensis Swain 

and Gilby, 1974 
CLUSTER ANALYSIS 19 

119 "Paijenborchella" sp. B =Acuminocythere sp. B 

132 H ermanites sp. A=" Lucasocythere" sanmartinensis Swain and Gilby, 

1974 

133 "Cytheretta" sp. B ="C." rothwelli Swain and 

Gilby, 1974 

167 Loxoconcha sp. E =Palmoconcha laevimarginata Swain and Gilby, 197 4. 

SHELF ASSEMBLAGES DEFINED BY CLUSTER ANALYSIS 

The clus.ter analysis of Holocene samples (fig. 8, 

9) indicates that the samples segregate into four 

major clusters on the basis of species content. These 

major sample clusters (actually provincial assemblages) define ostracode faunal p·rovinces. In general, they are areally equivalent to molluscan 

provinces (J. W. Valentine, 1966, figs. 1, 4), and 

rather than propose new names for the ostracode 

provinces, molluscan provincial terminology will be 

retained. Latitudinal discrepancies betwe~en ostracode and molluscan (sub) provincial boundaries are 

summarized below. 

Molluscan 

provinces 

OREGONIAN 

Mendocinan 

Montereyan 

---34°30' 

CALIFORNIAN 

Latitude 

North 

49 

Ostracode 

provinces 

______ 48°24' (limit of 

48 study area) 

* * northern 

* 

39 ______ 38°30' 

38 OREGONIAN 

37 southern 

36 

35°30'--

35 

northern 

34 ______ 

33 

32 CALIFORNIAN 

southern 

31 

30 

29 

---28°15'------------

28 

27 

26 northern 

SURIAN SURIAN 

25 ______ 24°45' 

24 

southern 

23 

---22°45'------------

Cluster 

A 

B 

c 

PANAMANIAN 22 PANAMANIAN D 

Cluster A (Oregonian ostracode province) contains samples occurring from the northern limit of 

the study area at Cape Flattery, Wash. (48°24' N.), 

south to latitude 35°30' N. near Point Piedras Elancas, Calif. (35°40' N.). Further, this cluster contains two subprovinces, a southern and northern, 

which segregate at latitude 38°30' N., south of Salt 

Point, Calif. (38°34" N.). Cluster A corresponds to 

the Oregonian mollus.can faunal province, although 

the subprovincial boundary within the ostracode 

province as well as the Californian-Oregonian ostracode provincial boundary are shifted to the north 1 o 

of latitude. 

Clus•ter B (Californian ostracode province) include~s samples extending from Point Piedras BlancaiS south to the Bahia Setiastian Vizcaino area (28° 

15' N.). This provinc.e, the approximate equivalent 

of the Californian molluscan province, also contains 

two subprovinces which segregate south of Point 

Conception in the region of the northern Channel 

Islands. The ostracode faunal nature of the Californian-Oregonian provincial boundary is discussed 

in the following s•ection. 

Cluster C, the Surian ostracode province, is equivalent to the molluscan province of the same name 

which extends from Punta Eugenia south to latitude 

22°45' N. south of Cabo San Lucas (22°52' N.) ; two 

subprovinces segregate at latitude 24°45' N., south 

of Cabo San Lazaro (24°48' N.). The two subprovinces are not discernible in molluscan studies. 

Cluster D is a small but distinctive group of samples occurring at the southern end of the study area 

off the west coast of Mexico. They, together with 

samples 4 and 5 (which cluster at a low level with 

samples of the Surian province), demonstrate a 

faunal discontinuity at latitude 22°45' N., south of 

Cabo San Lucas (22°52' N.). Cluster D lies in the 

northe·rnmost part of the Panamanian molluscan 

faunal province. 

The problem of deciding which clusters represent 

groupings of faunal-province magnitude is difficult 

and must be resolved subjectively. Delineation of 

known major provinces by cluster analysis provides 

a somewhat quantitative basis for the compa.rison of 

sample clusters and the detection of new provinces 

and subprovinces. Major provincial boundaries delineated by cluster analysis coincide in most cases 

with those previously determined by other means. 

Discussion of faunal provinces in the following 

sections refers to those based on ostracode distributions (table 5 and figs. 5, 9, and 13) unless otherwise 

indicated. 
20 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

OTSUKA COEFFICIENT OF SIMILARITY 

100 

Capf> Flattery ~ 108 

4d0 24' 107 

106 

105 

104 

103 

102 

101 

100 

99 

98 

97 

96 

95 

90 80 70 60 50 40 30 

Northern subprovince 

94 

93 

92 

91 

90 

89 

88 

87 

86 

85 

84 

83 

82 

79 

81 

80 

78 

77 

76 

75 

74 

73 

72 

71 

Oregonian province 

Salt Point ~ ~g 38°34' ~ 

66 

65 

64 

63 

62 

61 

60 

59 

58 

pt_ Piedras Blancas ~ 57----' 

35°40' ~ 

pt_ Conception ~ 

34°30' 

N. Channel Is. ~ 

34°00' 

54 

53 

52------., 

51---__.J 

50 

Southern subprovince 

Northern subprovince 

49 

48 

47 

46 

45 

44 

43 

42 

41 

40 

39 

38 

37 

36 

35 

34 

33 

32 

31 

30 

Californian province 8 

Bahia S. Vizcaino 29 

28"15' ~28 

27----~ 

Punta Eugenia ~ 26 

2J052' ~~ 

23 

22 

21 

20 

19+-----, 

18 

17 

16 

15 Cabo San Lazaro~ 14----_.J 

24°48' g -t------, 

11 

10 

9 

8 

7 

Southern subprovince 

Northern subprovince 

Surian C 

province 

Cabo San Lucas ~ 6 ------' Southern subprovince 

22°52' ~~6 =====::::::J--_j 

~ ~------------------~ 

3--------~ 

2 

1 

100 

I 

90 80 

Panamanian 

70 60 50 40 30 

20 

A 

D 

20 

10 0 

I I 

10 0 

FIGURE 8.-Dendrogram of Holocene sample clusters. Samples are compared on the basis of their ostracode species composition using the Otsuka similarity coefficient ( C IV N1N2) X 100; clustering was by the unweighted pair-group method. 
FAUNAL CHARACTER OF PROVINCES 21 

0 

I 

0 

Q) 

z-

<t~ - Q) 

zc. 

a::: E 

Oa> 

LL.-

::JE 

<( .... 

()~ 

3: 

z 

<( 

zro 

<( .!::! ~c. 

<(e 

Zl-

<( 

Q.. 

s. 

300 MILES 

I I ,· I 

300 KILOMETRES 

FIGURE 9.-The geographic extent of faunal provinces 

and climatic zones of the eastern Pacific shelf based 

on distributions of ostracode species. 

FAUNAL CHARACTER OF PROVINCES AND 

PROVINCIAL BOUNDARIES 

As noted, 192 diagnostic species out of a total of 

341 Holocene species have been used in this zoogeographic study. The geographic ranges of Holocene 

species and the occurrence of species in Pliocene and 

Pleistoeene units are shown in table 4, and some of 

the important members of the fauna are illustrated 

in the plates. Of the 56 genera treated in the total 

fauna (Holocene and fossil), 50 occur in the Holocene, and 9 are particularly diverse. Others, though 

less diverse, are important members of the fauna. 

The generic ranges which will now be dis.cussed are 

bas·ed on the results of this study and, for occurrenees in the Panamanian province, the literature 

was a determining factor. The Gulf of California is 

considered to be pa.rt of the Panamanian province. 

The genus Ambostracon contains 21 species, 20 of 

which occur in the Holocene. Ambostracon is found 

in all provinces, but reaches its highest diversity in 

the Californian province. Loxoconcha, comprising 8 

Holocene species, ranges throughout all four provinces. Another diverse genus, Caudites, is represented by 15 s.pecies in the Holocene, all but one of 

which occur in the Surian province. Eleven species 

of Caudites are endemic to the Surian, and the genus 

is restricted to the south of Point Piedras Blancas. 

Caudites is also recorded in the Panamanian 

province. 

Kangarina contains 9 species (8 occur in the Holocene) and is mainly an element of the Californian 

and Surian provinces; it is also known to occur in 

the Panamanian. Likewise, Paracytheridea (8 Holocene species) is found only in the Panamanian, Surian, and Californian provinces. H emicytherura is 

represented by 12 species which are rather evenly 

distributed throughout the study area, although it is 

not yet known from the Panamanian province. 

"Hetnicythere" is an undescribed genus based on 

LeRoy's (1934a) Hmnicythere? californiensis (two 

forms recognized by LeRoy) and H.? hispida forms. 

This taxon includes 10 species, 9 of which occur in 

the Holocene, and it is found chiefly in the Californian province and the northern Surian subprovince, 

although it is reported from the Panamanian province (Gulf of California; Swain, 1967). H erma,nites 

includes 9 species, 8 occurring in the Holocene; the 

genus occurs in the Californian and Surian provinces, and it too has been reported from the Gulf of 

California. 

"Aurila" is an undescribed genus (or genera) and 

comprises 8 species, 6 of which occur in the Holocene. This group has representatives throughout the 

four provinces. Radimella ( 4 species occurring in 

the Holocene) occurs chiefly in the Californian and 

more southern provinces, but 1 species ranges into 

the southern Oregonian subprovince. "Radimella," 
22 

No. 

001 

002 

003 

004 

005 

006 

007 

008 

009 

010 

011 

012 

013 

014 

015 

015F 

016 

016F 

017 

018 

019 

020 

021 

022 

023 

024 

024F 

025 

026 

027 

028 

029 

030 

031 

032 

O:.J3 

034 

035 

036 

037 

038 

039 

U40 

040F 

041 

042 

042F 

043 

044 

045 

046 

047 

048 

049 

050 

051 

052 

053 

054 

055 

056 

057 

058 

059 

060 

061 

062 

063 

064 

065 

066 

067 

068 

069 

070 

071 

072 

073 

074 

075 

076 

077 

078 

ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

TABLE 4.-Holocene geographic ranges and fossil occurrences of ostracode species in the study area 

[F=species occurs only in fossil deposits] 

Holocene geographic range 

Fossil occurrence 

San Pedro 

Species 15-minute 

sample 

range 

Maximum 

latitudinal range 

(north) 

San 

Diego 

Formation 

Format~ Palos B~~~!~a Foxen Careaga 

Lomita TJ:~s Verdes Forma- Mtud- SstaonndeAmbostracon sp. A ------------------ Aurila lincolnensis ------------------- Kangarina sp. A --------------------- Aurila sp. A ------------------------- Hermanites sp. G --------------------

Aurila sp. B ------------------------- f!-urilf! ;~nontereyensis ----------------- Aunla sp. C -----------------------

Aurila sp. C ------------------------- A. sp. D ----------------------------- Hemicythere sp. A ------------------- H.? sp. C ----------------------------

H. sp. B ----------------------------- Triebelina reticulopunctata __ ---- ____ _ 

Cativella sp. B ----------------------- A1nbostracon sp. C -------------------

f:tery_g~?ythereis? sp. A -------------- Aunla sp. G -----------------------

Cativella sp. A ---------------------- Pulmilocytheridea pseudoguardensis __ _ 

Puriana pacifica ---------------------

Caudites fragilis --------------------- Caudit··s sp. J ---------------------- Caudites sp. B -----------------------

Caudites purii ----------------------- Puriana sp. A ----------------------- "Aurila" sp. H -----------------------

Caudites sp. D -----------------------

Radimella palosensis ----------------- Caudites sp. E -------------------··---

"Radimella" aurita -------------------- Coquim.ba sp. A ----------------------

Radimella sp. A ------------------~---

R. sp. B ----------------------------

Sahnia sp. A ------------------------ Pontocythere sp. C -------------------

Triebelina sp. A --------------------- Cythere maia ------------------------ Kangarina sp. B ---------------------

Cythere sp. A ----------------------- Kangarina sp. C -----------------·---- Cythere sp. B ------------------------ "Trachyleberis" sp. A ----------------

Bythocythere sp. A ------------------- Caudites sp. L ----------------------- "Trachyleberis" sp. B ----------------

Coquimba sp. B ---------------------- Cytherelloidea sp. A ------------------

C. sp. C ---------------------------- Kangarina aff. K. quellita ------------

"Cytheretta" sp. A -------------------

Pellucistoma sp. B ------------------- Cytheromorpha sp. A ---------------- Pellucistoma bensoni ----------------- Cytheropteron sp. A ------------------

Pellucistoma sp. A ------------------ Palaciosa sp. C ---------------------- Ambostrncon sp. Q -------------------

Hemicytherura sp. A ----------------

~u~fz~,B c~iij;;~ic~--============== ==== 

Hemicytherura sp. C ----------------- Munseyella pedroensis ---------------- Hemicytherura sp. D -----------------

H. sp. F ---------------------------- Pectocythere clavata ----------------- Hemicytherura sp. H -----------------

H. sp. G ---------------------------- H. sp. I ----------------------------- H. sp. E ---------------------------- H. sp. J ---------------------------- H. sp. K ---------------------------- H. sp. L ---------------------------- Cativella semitranslucens ------------- Hermanites kewi --------------------- H. sp. B ---------------------------- H. sp. F ---------------------------- H. sp. C ---------------------------- H. sp. D ----------------------------- Caudites sp. M ----------------------

f:;_:t;:::f::::~ s

8

:.· f -================== "Bradleya" simiensis -----------------

053-108 

028-108 

034-044 

028-108 044 

026-057 

053-107 

028-063 

036-085 

014-057 

064-108 

109, 110 

006-014 

081-108 

021-051 

001-003 

001-003 

023-056 

014-036 

109, 003-056 

023-057 

109 014-052 

021-028 

001-003 

109, 006-026 

014-068 

109, 006-026 

014-062 

022-051 

109, 110 006-045 109, 110, 

006-023 

023-107 

053-108 

025-049 

022-057 

034-045 

069-108 

021-067 

067-108 

001-003 

110 

001-003 

109, 

006-050 109, 110 109, 110, 006-026 

052-108 

014-027 

056-108 

023-051 

067-108 

025-049 

049-059 

021-025 

053-108 

053-108 

109, 110, 

003-045 

021-052 

027-053 

056-107 

006-041 

049-052 

034-059 

006-014 

036-107 

082-108 

034-107 

027-049 

034-081 

028-052 

046-057 

021-028 

025-034 

028-050 

026-056 

014-026 

028-068 

0::!6-108 

047-050 

34 "30' -48"30' 28"15'-48"30' 

29"45'-32"30' 

28"15'-48"30' 

32"15'-32"30' 

27"45'-35"45' 

34"30'-48"15' 

28"15'-37"15' 

30"15'-42"45' 

24"45'-35"45' 

37"15'-48"30' 

22"45'-25"00' 

41 "30'-48"30' 26"30'-34"15' 

21 "30'-22"15' 

27"00' -35"30' 24"45'-30"30' 

22"00'-35"30' 

27"00'-35"45' 

23"15'-23"30' 

24"45'-34"30' 

26 "30' -28"30' 21 "30'-22"15' 

22"45'-28"00' 

24"45'-38"30' 

22" 45' -28"00' 

24"45'-37"00' 

26"45'-34"15' 

22"45'-32"45' 

22"45'-27"15' 

27"00'-48"15' 

34"30'-48"30' 

27"30'-33"45' 

26"45'-35"45' 

29"45'-32"45' 

38"30'-48"30' 

26"30'-38"15' 

38"00'-48"30' 

21 "30'-22"15' 

23"30'-23"45' 

21 "30'-22"15' 

22"45'-34"00' 

23"15'-23"45' 

22"45'-28"00' 

34"15'-48"30' 

24"45'-28"15' 

35"15'-48"30' 

27"00'-34"15' 

38"00'-48"30' 

27"30'-:'!3"45' 

33"30'-36"15' 

26"30'-27"45' 

34 "30' -48"30' 34"30'-48"30' 

22"00'-32"45' 

26"30'-34 °30' 28"00' -34 ° 45' 35"15'-48"15' 

22"45'-:H "45' 33"30'-34"30' 

29"45'-36"15' 

22"45'-2'5"00' 

30°15'-48"15' 

41 °45'-48°30' 29°45'-48"15' 

28"00'-33°45' 

29"45'-41 "45' 28"15'-34"30' 

32"45'-35°45' 

26"::W'-28"~o· 

27"30'-30"00' 

28"15'-34°00' 

27"45'-35"30' 

24"45'-28"00' 

28"15'-38"::!0' 

30°15 I -48"30' 33"00'-34"00' 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Marl Silt Sand tion s one 

Member Member 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 
No. 

079 

080 

081 

082 

083 

084 

085 

086 

087 

088 

089 

090 

091 

092 

092F 

093 

094 

095 

096 

097 

098 

099 

100 

100F 

101 

102 

103 

104 

105 

105F 

106 

106F 

107 

108 

109 

110 

111 

112 

113 

114 

115 

116 

117 

118 

119 

120 

121 

122 

123 

124 

125 

126 

127 

128 

129 

130 

131 

132 

133 

134 

135 

136 

137 

138 

139 

140 

140F 

141 

142 

143 

144 

145 

146 

147 

148 

149 

150 

151 

152 

153 

154 

155 

155F 

156 

157 

158 

FAUNAL CHARACTER OF PROVINCES 23 

TABLE 4.-Holocene geographic ranges and fossil occur'rences of ostracode species in the study area-Continued 

Species 

Loxoconcha sp. A -------------------- Loxocorniculum sp. B ----------------

Loxoconcha helenae ------------------ L. lenticulata ------------------------ L. sp. B ---------------------------- L. sp. D ---------------------------- L. sp. C ----------------------------- Loxocorniculum sp. A ---------------- Coquimba pichelinguensis ------------

Munseyella sp. A -------------------- M. sp. C -----------------------------

M. sp. B ---------------------------- Ambostracon sp. B ------------------

Costa? sanfelipensis ------------------ Buntonia sp. C ---------------------- Ambostracon glaucum ---------------- A. diegoensis ------------------------ A. sp. J ---------------------------- Buntonia sp. B _ ----------------------

Ambostracon sp. K ------------------

A. sp. N ----------------------------

A. sp. L ---------------------------- Cativella unitaria -------------------- Buntonia sp. A ---------------------- Ambostracon sp. E ------------------

Basslerites sp. B --------------------- Ambostracon sp. G ------------------- Basslerites delreyensis ---------------- C1Jtherelloidea sp. B ------------------ Cytheropteron sp. B ----------------- C. dobladoensis ----------------------

;;Hem_icyth;,re': sp. ~ ----------------- "Ra,~tmella :~ollae~BlB _________ ------- A. schttmannenBtB ____________ ------

::Rad~m~lla" pacifica ------------------ Aunla sp. D -----------------------

Radimella sp. A ---------------------

;;1::: d~iv;;.i -========================== Ambostracon sp. P ------------------- Cytheropteron johnsonoides ---------- Ambostracon sp. 0 ------------------ "Paljcnborchella" sp. A ---------------

Ambostracon sp. I ------------------- "Paijenhorchella" sTJ. B ---------------

Ambostracon sp. F ------------------

,c;audi~es sp .• ft. --~----:---:-----------­ "Hem~c'Jjthere, caltfornwnBtB ---------- Hemwythere sp. A ----------------- "H." sp. F ---------------------------

"H." so. E -------------------------- Ambostracon microreticulatum · ------- Cytheromorpha sp. B ---------------- Neocaudites? henryhowei ------------- "Cytheretta" sp. C -------------------

~:mFc~~~!rJ. ~~: ~ ================= Hermanites sp. A -------------------- "Cytheretta" so. B -------------------

Orionina pseudovaughni --------------

Palaciosa sp. A ---------------------- Cytherelloidea californica ------------- Palaciosa sp. B ---------------------- Cytherella banda --------------------- Palaciosa sp. D ---------------------- Cytherella sp. A --------------------- Hermanites sp. H -------------------- Palmenella californica ---------------- Paracytheridea sp. B -----------------

P. sp. A ---------------------------- P. sp. C ----------------------------- P. sp. D ---------------------------- P. granti ---------------------------- Pectocythere sp. A -------------------

P. tomalensis ------------------------ Kangarina sp. H -------------------- Ambostracon californicu= ------------ A. costatum ------------------------- A. sp. D ---------------------------- Puriana sp. B ----------------------- Ambostracon sp. M ------------------ Basslerites thlipsuroidea ------------- Kangarina sp. G --------------------- Caudites sp. C ----------------------

C. sp. K ---------------------------- Coquimba schencki -------------------

Holocene geographic range 

15-minute 

sample 

range 

056-108 

109, 110 006 

051-085 

041-052 

025-063 

036-048 

034-052 

023-049 

109, 110 006-026 

036-045 

062-108 

045-095 

045-108 

001-003 

028-057 

028-050 

014-057 

048-051 

109, 006-014 

021-050 

028-051 

003 

053-108 

028-041 

021-108 

036-065 

003 

!Hll-003 

021-108 

062-108 

014-073 

028-057 

028-108 

063-108 

028-056 

022-027 

003-006 

023-050 

053-108 

023-034 

056-071 

041-051 

045-057 

027-071 

027-051 

022-027 

025-036 

028-056 

051-108 

026-045 

041-052 

067-108 

014-036 

026-036 

025-052 

109, 110, 

001-023 036-068 

006-056 

034-065 

936-051 

022-034 

001-003 

025-056 

022-051 

022-057 

021-050 

023-041 

041-050 

053-108 

062-108 

048-050 

050-051 

048-051 

050-056 

006 

049-108 

001 

109, 110, 006-014 

109 

028-051 

Maximum 

latitudinal range 

(north) 

35°15'-48°30' 

22°45'-23°45' 

34°00'-42°45' 

31 ·3o'-34 •so• 27°30'-37°15' 

30°15'-33°30' 

29.45'-34°30' 

27°00'-33°45' 

22°45'-28°00' 

30°15'-32°45' 

36°45'-48°30' 

32°30'-45°15' 

32°30'-48°30' 

21 •so'-22•15' 

28°15'-35°45' 

28•15 '-34 ·oo· 24°45'-35°45' 

33°15'-34°15' 

22°45'-25°00' 

26°30'-34°00' 

28°15'-34°15' 

22°00'-22°15' 

34 °30'-48°30' 

28°15'-31 °45' 26°30'-48°30' 

30°15'-37°45' 

22°00'-22°15' 

21 ·so'-22•15' 

26°30'-48°30' 

36°45'-48°30' 

24°34'-39°45' 

28°15'-35°45' 

28°15'-48°30' 

37°00'-48°30' 

28°15'-35°30' 

26°45'-28°15' 

22•oo'-2"3•oo• 

27°00'-34°00' 

34°30'-489 30' 

27•oo• -3o·oo· 35°15'-39°15' 

31 °30'-34°15' 32°30'-35°45' 

28°00'-39°15' 

28°00'-34°15' 

26°45'-28°15' 

27°30'-30°30' 

28°15'-35°30' 

34°00'-48°30' 

27°45'-32°45' 

31°30'-34°30' 

38·oo'-48.30' 

24°45'-30°30' 

27°45'-30°30' 

27°30' -34 •3o' 21 •30'-27•15' 

30°15'-38°30' 

22°45'-35 .. 30' 29°45'-37°45' 

30°15'-34°15' 

26°45'-30°00' 

21 •30'-22•15' 

27°30'-35°30' 

26°45'-34°15' 

26°45'-35°45' 

26°30'-34°00' 

27°00'-31 °45' 31 ·3o'-34"oo' 

34°30'-48°30' 

36°45'-48°30' 

33°15'-34°00' 

33°45'-34°15' 

33°15'-34 °15' 33°45'-35°30' 

22°45'-23°00' 

33°30'-48°30? 

21 •30'-21 °45' 

22°45'-25°00' 

23°15' -23°30' 28°15'-34°15' 

San 

Diego 

Formation 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

·x 

X 

X 

X 

>< 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Fossil occurrence 

San Pedro 

Format~ Palos Santa T Barbara Lomita Pcl:s Verdes FormaMarl Silt Sand tion 

Member Member 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Foxen Careaga Mud- Sand- stone stone 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 
24 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

TABLE 4·-Holocene geographic ranges and fossil occurrences of ostracode species in the study area-Continued 

Holocene 

geographic range 

Fossil occurrence 

San Pedro 

Format~on Palos Santa 

No. 

159 

160 

161 

162 

163 

164 

164F 

165 

166 

167 

168 

169 

170 

171 

172 

173 

174 

174F 

175 

176 

177 

178 

178F 

179 

180 

181 

182 

183 

184 

185 

186 

187 

188 

188F 

189 

190 

191 

192 

193F 

194F 

195F 

196F 

Species 

Pontocythere sp. A ------------------ New genus D sp. A ----------------- gytheropteror~;, n~WJ?Ortense ----------- Hemwythere htsptda ---------------- "H." sp. D --------------------------- Eucytherura sp. A ------------------

~J/!:~ic:ftt·e/e;' ~P~-G-~===~~===~~===~~= Hermanites sp. E --------------------

Loxoconcha sp. E --------------------

Loxocorniculum sculptoides ----------

Lo:r:oconcha sp. F --------------------

"Loxoconcha" emaciata ---------------

"Bradleya" pennata ------------------ New genus A sp. A ------------------ Paracytheridea sp. E -----------------

Basslerites sp. C --------------------- Munseyella similis? ------------------ Paracytheridea sp. F ___ --------------

P. sp. G ----------------------------- Caudites sp. H -----------------------

Bythoceratina sp. A ------------------ Munseyella sp. D -------------------- Pellucistoma scrippsi -----------------

Perissocytheridea pedroensis ---------- Caudites sp. F ----------------------- "Radimella" sp. B --------------------

R. convergens ----------------------- Kangarina sp. D ---------------------

!fHe~icy~he;~;;-~-p~-B-================= "Cytherctta" corrugata --------------- Kangarina sp. F --------------------- New genus B sp. A ----------------- Pectocythere sp. B -------------~----­

Caudites sp. G -----------------------

0. sp. I ----------------------------- Pontocythere sp. D ------------------ New genus C sp. A ------------------ New genus E sp. A ------------------ Paijenborchella sp. A ---------------- Pectocythere sp. D -------------------

15-minute 

sample 

range 

044-050 

052-068 

05Q-052 

048-051 

041-050 

001-003 

048-052 

036-049 

109, 110, 003-050 

109, 110, 006-014 109, 110, 006-014 109, 110, 006 

028-056 

028-050 

041-051 

001 

109, 110, 006 

041-050 

109, 110, 006 003 

109, 110, 006-052 

045-050 

006-014 

028-051 

109 

036-049 

006 

044-051 

041-051 

003 

088-108 

014 

014 

006 

another undesc:ribed genus (o~ genera) comprising 

5 Holocene species, occurs in the Surian, Californian, and Oregooian provinces. 

Cythere, a genus usually restricted to northern 

latitudes in other parts of the world (Hazel, 1970), 

includes 3 species in the study area, 2 of which occur 

in the Oregonian province and probably range farther north. One species, however ( Cythere maia) , is 

confined to the Californian and northern Surian subprovince, and although it is very similar to one of 

the northern species ( Cythere sp. B) , it is distinctive, and their ranges do not overlap. Its present distribution may be the result of southward migration 

facilitated by the cooling of coastal waters by upwelling. H emicythere, represented by 2 Holocene 

species, is another cryophilic genus (Hazel, 1970), 

and it occurs only in the Oregonian province and 

most probably farther north. 

Foxen Careaga Maximum 

latitudinal range 

(north) 

San 

Diego 

Formation 

T Barbara 

Lomita ~cl:s Verdes Forma- Marl Silt Sand tion 

Mud- Sand- stone stone 

Member Member 

32°15 1-34°00' 34 O 15 I -38"301 

33°45 1-34°301 

33°15 1-34°15 1 

31°30 1-34°00' 21 °30'-22°15' 

33;15·:.34-;,30-; 

30°15'-33°45' 

22°00 1-34°00 1 

22°45 1-25°00' 

22° 45 I -25 ooo~ 

22°45 1-23°45 1 

28°15 1-35"30 1 

28°15 1-34"00' 31 "30 1

-34 "15' 21 •301

-21 •45 1 

22"45 1-23°45 1 

31 "30 1-34°00 1 

22°45 1-23"45' 

22"00 1-22"15 1 

ii;45~:.34o3o-; 

32"301-34"001 

22"45 1-25°001 

28°15 1-34°151 

23°15 1-23°301 

30"15'-33°45 1 

22°45 1-23"00' 32"15'-34°15' 

31 "301-34 °151 

22°001-22"15' 

43°15'-48"301 

24°45 1-25"00' 24"45'-25"001 

22°45 1-23°00' 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

A sum~ma,ry of the provincial distribution of these 

and other important genera follows. Numbers in 

parentheses indicate, first, species occurring in the 

Holocene and, secondly, species occurring only in the 

Pliocene or Pleistocene. 

Panamanian-Oregonian provinces : 

Ambostracon (20: 1) 

"Aurila" 

Cytheropteron 

"H mnicythere" 

Kangarina 

Loxoconcha 

Pontocythere 

Radimella 

(6; 2) 

(4; 1) 

(9; 1), mainly Californian 

and south. 

( 8 ; 1) , mainly Californian 

and south. 

(8; 0) 

(4: 0) 

( 4 ; 0) , mainly Californian 

and south. 
FAUNAL CHARACTER OF PROVINCES 25 

Panamanian-Californian provinces : 

Cativella (4; 0) 

Caudites 

Coquimba 

Cytherelloidea 

Hermanites 

Loxocorniculum 

Paracytheridea 

Pellucistoma 

Puriana 

(15; 0) 

(3; 1) 

(4; 0) 

(8; 1) 

(3; 0) 

(8; 0) 

(4; 0) 

(3; 0) 

These genera do not range north of Point 

Piedras Blancas. 

Surian-Oregonian provinces: 

A urila ( 6 : 0) , mainly Californian 

Cythere 

"Cytheretta" 

H emicytherura 

Munsey ella 

"Radimella" 

and north. 

(3; 0) 

( 4 ; 0) , mainly Californian 

and north. 

(12; 0) 

( 4; 2), mainly Galifornian 

and north. 

(5; 0) 

Californian-Oregonian provinces : 

"Paijenborchella" (2; 0), does not range 

south of Point 

Conception. 

Pectocythere (4; 1) 

· Oregonian province: 

H emicythere (2; 0), does not range 

south of Point 

Piedras Blancas. 

This summary clearly indicates the magnitude of 

the faunal diHcontinuity between the Californian and 

Oregoni,an p.rovinces. Nine important genera terminate their northern ranges in the Californian province. The nature of other provincial boundaries, 

namely the Pana.manian-Surian and the SurianCalifornian, a.re not a:s well understood on the basis 

of generic distributions. From the information at 

hand, it seems that the Pana.manian-Surian discontinuity may be of the magnitude of the CalifornianOregonian break. The Surian-Ca.lifornian faunal 

boundary is probably of less magnitude, as indicated 

by the fact that these two provinces show more similarity to each other than to either the Oregonian or 

Panamanian provinces (fig. 8). 

The distributions of ostracode genera provide a 

broad outline of provincial configuration. The faunal 

character of a p·rovince can be more precisely evaluated on the basis of the numbers of species it contains and their distribution pattern.s within and outside of the province (tables 4, 5) . The northern limit 

of the study area apparently does not include the 

northern boundary of the Oregonian provinc·e, and 

therefore comparative figures on the occurrences of 

species in this province are incomplete. 

TABLE 5.-Distribution of inner sublittoral ostracode species and their occurrence in faunal provinces off the west coast of North 

America 

[Based on 143 species which range through at least 2° of latitude; also included are 28 species which exhibit short ranges or single occurrences in the 

Panamanian province and adjacent southern Surian subprovince and are considered to represent northern distributional limits of southern species] 

I 

Eastern Pacific faunal province PAN AM·. 

Subprovince I 

I 

Latitude north 21 22 

I 

Northern range end points of ostracode species l 16 I 

I 

I 

Southern I range end points of ostracode species t 4 

I 

Endemic species -

Species ranging through ? 

Species in common -

Total species 20 

I 

* 36 species range north to 48°24'N (limit of study area), and 

it is not known at this time how many range on northward. 

SUR IAN 

s North 

?3 24 ~5 26 27 2a 

12 15 

27 

17 45 

62 

0 2 

14 

4 8 

3 

21 

33 66 

78 

I 

CALIFORNIAN OREGONIAN I 

South IN South North I 

I 

29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48i 49 

34 129 22 7* ~ I 

63 29 ! 

49 116 8 4 I 

I 

65 12 I IV 

I ~ 

13 I o 0 ? I IV 

1>- "C I ::J 

27 ? !ti 

137 

.... 30 31 ·? I o I~ : _; 15 ? I..J 

39 I 

66 I 

100 (82 61 42' I 

I 

I 116 64 ! 
26 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

Of the 171 species treated in table 5, the Oregonian, Californian, and Surian provinces contain 64, 

116, and 78 sp,ecies, respectively. A similar diversity 

trend was noted in mollusc,an distributional studies 

(J. W. Valentine, 1966, table 2). The increase in 

diversity from the Oregonian to the Californian 

province conforms to the gene,rally recognized latitudinal diversity gradient which increases from 

polar to equa,torial regions. Ostracode a:s well as 

molluscan diversity decreases from the Californian 

to the Surian province, however. This reduction in 

the number of species may simply be the result of a 

lack of adequate sampling along the coasts of southern Baja California, or it may be partially due to 

lower habi·tat diversity in the Surian province, 

which is smaller areally than the Californian. 

The boundary between the Californian and Oregonian provinces is cha~acterized by many range 

endpoints. This boundary is es~sentially the result of 

northern range terminations of thermophilic sp~ecies 

and actuaUy occurs in two steps____,a southern break 

between the southern and northe,rn subp·rovinces of 

the Californian province at 34 o N. where, within 1 o 

of latitude, 37 southern species end their rangeiS 

(contrasted with only 6 endpoints of northern 

species), and a northe'rn break between the Californian and Oregonian province at about 35°30' N. 

where 19 thermophiles end their ranges within 1 o of 

latitude ( agains~t only 4 southern endpoints for cryophiles). This major faunal discontinuity is related 

to the marine climatic re·gime (figs. 6, 7). The southern faunal elements encounter the coolest water in 

their ranges in the area between 34° N. and 35°45' 

N. where the temperature minimum is 11 o to 12° C. 

It is difficult to ascertain whether the temp·e,rature 

minima represent a survival limit for the northward-ranging thermophiles, or whether the maximum yearly temperatures are more important. The 

minimum yearly temp,eratures of 11 o to 12° C in this 

area also occur to the north, whereas the maximum 

yearly temperatures of 14° to 17° C do not, an indication that maximum water temperatures may not 

be high enough to permit repopulation, thus limiting 

the northwa,rd expansion of thermophilic speeie,s. 

Southw'ard ranging cryophiles are little affected because the thermal maxima in this area (14° to 17° 

C), which they tolerate, extend continuously farther 

south within the Californian province due to upwelling along the coast (figs. 5, 6, 7). 

The boundary between the Californian and Surian 

provinces is characterized by the occurrence of 

range endpoints of northe:rn species and is of les,ser 

magnitude (see fig. 8, where clusters B and C indicate closer affinity than do A and B.) At this boundary 26 cryophiles end their ranges within 1 o of latitude while only 6 thermophiles drop out. In fact, 49 

southward-ranging species terminate their ranges in 

the southern Californian subprovince, and they drop 

out in a stepwise manner southward, an indic,ation 

that these speeies a.r'e reaching their temperature 

limits in areas where temperature maxima are 

dampened by upwelling. They may be reacting to 

increased temperature and survival limits or to the 

failure of upwelling to produce tempe,ratures low 

enough to allo·w repopulation. T·emperature minima 

enhanced by upwelling occur both north and south of 

the Californian-Surian boundary at Punta EugeniaBahia S. Vizcaino. Cryophilic spedes ranging southward past this boundary must pass through an apparent barrier of shallow, relatively warm waters of 

the bay to reach the cool, upwelled waters south of 

Punta Eugenia; they must then be ~able to tolerate 

still higher temperature's during thermal maxima in 

an area where upwelling occurs only seasonally. 

The northern and southern Surian subprovinces 

are similar in that their northern boundaries are 

marked by promontorries where seasonal upwelling 

lowers the tempe·ra.ture markedly; to the south, however, the coasts are embayed and little or no upwelling occurs. Beeause thes~e wa.ters a.re warmed both by 

solar radiation and by a warm surface countercurrent in the summe1r and fall, the annual range of 

temp·erature is greater (a,s much as 10° C in the 

areas where seasonal upwelling occurs) than that 

(3° to 6° C) to the north in the Californian province. 

Many eryophilic species (62), chiefly from the Californian province where waters are cooler, end their 

range1s in the Surian province. They can survive temperature minimra in the upwelling areas of the 

Surian province, but temperature maxima limit their 

southward movem:ent. Pe,rhaps they survive where 

they do beeause minimum temperatures are cool 

enough for repopula;tion to occur and maximum temperatures are not high enough to kill. When temperatures remain too high for repopulation or become 

high enough to be lethal, these species can no longer 

expand southward. Of the 27 species which end their 

nnrthern expansion 'in the Surian province, many 

are endemic. It is possible that their range records 

will he extended southward when be.tter collections 

can be made in this area and in the adj aeent Panamanian province. Formidable thermal barriers limit 

the northward expansion of species through the 

Surian province, principally the two large areas of 

upwelling to the south of Cabo San Lazaro and 

Punta Eugenia (fig. 5). Maximum temperatures in 
FOSSIL COLLECTIONS 27 

these regions may well be tolerated by southern species, but minima due to upwelling can be more than 

10o C lower than maxima and probably reach the 

killing temperatures of many species. 

The Panamanian province is here represented by 

only a few samples which contain a total of 20 species, 16 of which do not occur in the Surian province 

to the north. This suggests that the Surian-Panamanian boundary represents a major faunal discontinuity in ostracode dis.tributions, but more detailed 

S1ampling is needed to verify this assumption. 

Although there are few species endemic to any 

province, there are also few that range through an 

entire province, though many range through each 

subprovince (tables 4 and 5). The nature of their 

geographic distribution illustrates the response of 

species to changes in the marine climate within provinces as well as at provincial boundaries. Although 

faunal provinces are equated with climatic zones, a 

practice which lends a somewhat quantitative aspect 

to the provincial marine climate, such usage should 

not be construed to indicate that a province exhibits 

a particular climate throughout. If this were the 

case, there would be many more endemic species, and 

range endpoints of species would occur almost exclusively at provincial boundaries, a situation which 

of course does not occur. 

It is noted in table 5 that the s.outhern Surian ' northern Californian, and southern Oregonian subprovinces do not contain any endemic species. These 

subprovinces occupy short segments of coastline and 

small areas of shelf compared to· other subprovinces, 

and they might be considered to represent areas of 

overlap of species chiefly confined to neighboring 

provinces. However, as shown in the cluster analysis 

(fig. 8), the subprovinces within each major province cluster at approximately the same level and 

therefore appear to constitute entities of equivalent 

importance. Although the importance of endemic 

species in defining faunal provinces has been emphasized by some workers (Ekman, 1953; Holland, 

1971), I feel that.faunal distinctiveness rather than 

the presence or absenee of a certain number of endemic species should be the crite,rion for recognition 

of a faunal province. Indeed, as has just been shown, 

endemic,s make up a very small proportion of the 

faunas of even the larger areas considered by most 

workers to represent faunal provinces; this situation has also been observed in molluscan studies 

(J. W. Valentine, 1966, table 2). 

MARINE PALEOCLIMATES OF SELECTED 

PLIOCENE AND PLEISTOCENE UNITS 

OF SOUTHERN CALIFORNIA 

A knowledge of the Holocene distributional patterns o.f the Ostracoda and determination of the marine climatic conditions which govern those distributions provide a basis for the initiation of paleoecologic analyses of fossil ostracode assemblages. Studies of ostracode (paleo)zoogeography will also provide a test for conclusions already drawn from more 

extensive investigations which have been conducted 

with the Mollusca and Foraminifera. It is hoped that 

s~tudies of a heretofore neglected group will contribute to an understanding of the factors controlling provincial biogeography in general. 

An effort has been made t9 utilize the information 

resulting from study of Holocene ostracode zoogeography to interpret marine climatic conditions during the late Cenozoic at selected locations along the 

coast of southern California. The paucity of information on ost~acode fossil assemblages on the west 

coast constrains the scope of the investigation. The 

results will therefore be of a preliminary nature. 

FOSSIL COLLECTIONS 

Collections were made from formations of Pliocene to Pleistocene age which occur in four areas 

along the California coast (fig. 3). These units and 

their gene·rally accepted ages include: San Diego 

Formation (late Pliocene age) at San Diego (32°48' 

N.); San Pedro Formation (early Pleistocene age) 

and the Palos Verdes Stand (late Pleistocene age) at 

San Pedro (33°44' N.); Santa Barbara Formation 

(early Pleistocene age) at Santa Barbara (34°25' 

N.) ; and the Foxen Mudstone (middle to late Pliocene age) and the Careaga Sandstone (late Pliocene 

age) of the Santa Maria district (34°54' N.). 

The stratigraphy of these units has been adequately described by others and will be only summarized 

herein. The ages of some of the formations treated 

here are in dispute, especially with respect to the 

placem·ent of the Pliocene-Pleistocene boundary in 

the west coast s.equence. Delineation of this boundary has been reviewed elsewhere (Woodring, 1952; 

J. W. Valentine, 1961; Bandy, 1967; Bandy and Wilcoxon, 1970). The we,st coast fossil ostracode assemblages are at this time too poorly known to contribute to the solution of this problem. Previous 

paleoecologic interpretations are based mainly on 

fossil molluscan and foraminiferal assemblages; 

they are review·ed in a later section. A register of 

fossil localities is in table 6. 
28 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

TABLE 6.-Register of fossil localities 

Mf2165-2167: 

Mf2168, 2169, 

2171, 2172: 

Pacific Beach, San Diego, Calif.; La Jolla 

7 .5' quad., 1953. Locality of Hertlein and 

Grant, 1944. San Diego Formation (upper 

Pliocene); approximately 400 ft (120 m) 

thick; unconformable on Eocene marine 

sandstones; unconformable under horizontal Bay Point Formation (upper 

Pleistocene) . 

Mf2165: San Diego Formation (upper 

Pliocene) ; in a gully in sea cliffs 

off Crystal Drive where it turns 

from east-west to north-south; 

shell bed in yellow-brown marine 

sands; about 100 ft (30 m) above 

Eocene-Pliocene contact. 

Mf2166: San Diego Formation (upper 

Pliocene) ; 35 ft ( 11 m) north of 

the end of Law Street in sea cliff 

facing Pacific Ocean; white sandy 

marl containing Pecten and echinoid fragments; about 100 ft (30 

m) above Mf2165 and approximately in the middle of the exposure at Pacific Beach ; about 20 ft 

(6 m) above high tide; from the 

beach to the sample locality the 

outcrop is covered by slumped material and a thick bed of tide-deposited cobbles. 

Mf2167: San Diego Formation (upper 

Pliocene); 4 ft (1 m) above 

Mf2166. 

Second St., between Pacific Ave. and Mesa 

St., San Pedro, Calif.; San Pedro 7.5' 

quad., 1964. Lomita Marl Member of San 

Pedro formation (lower Pleistocene) consists of approximately 50 ft (15 m) of 

marls and calcareous sands; Lomita over-

. lain unconformably by Timms Point Silt 

Member of San Pedro Formation (lower 

Pleistocene) which consists of about 80 

ft (24 m) of fossiliferous marine silty 

sands. Horizontal Palos Verdes Sand 

(upper Pleistocene) unconformably overlies the Timms Point. Localities 42-44 of 

Woodring and others, 1946. (See their 

p. 46 for measured sections.) 

Mf2168: Lomita Marl Member (lower 

Pleistocene) ; fine-grained marl ; 

lowest sample in Lomita (base not 

exposed) ; in an alley across from 

a bakery on north side of Second 

St. 

Mf2169: Lomita Marl Member (lower 

Pleistocene) ; coarse marl; north 

side of Second St. in middle of 

Lomita ex'J)osure and a'J)p-roximately 25ft (8 m) higher than M-F21.68. 

Mf2171 : Timms Point Silt Member 

(lower Pleistocene) ; shell bed in 

fine-grained marine silty sands; at 

Lomita-Timms Point contact on 

TABLE 6.-Register of fossil localities-Continued 

Mf2170: 

Mf2173: 

Mf217 4, 2175, 

2176: 

Mf2177, 2178, 

2179: 

south side of Second St.; contact 

burrowed downward into Lomita. 

Mf2172: Timms Point Silt Member 

(lower Pleistocene) ; shell bed 20 

ft ( 6 m) above Mf2171 and 6 ft 

(2 m) below Palos Verdes Sand. 

Lomita Quarry, Torrance, Calif.; Torrance 

7.5' quad., 1964, (not shown on this map; 

see Woodring and others, 1946, pl. 1; also 

Galloway and Wissler, 1927). 

Mf2170 : Lomita Marl Member (lower 

Pleistocene); marl; near top of 

formation; "upper foram bed" of 

Galloway and Wissler, 1927. 

Vacant lot west of Pacific Ave. between 

Bonita St. and Miner St., San Pedro, 

Calif.; San Pedro 7.5' quad., 1964. 

Mf2173: Palos Verdes Sand (upper 

Pleistocene) ; collected in 2-3 ft (1 

m) of shelly marine sands. 

West side of Shoreline Drive, south of 

Castillo St. and 0.1 mile (163 m) southwest of the municipal pool in Santa Barbara, Calif.; Santa Barbara 7.5' quad., 

1952. Santa Barbara Formation (lower 

Pleistocene) consists of about 70 ft ( 21 

m) of silty bryozoan marls, and unconformably overlies the Sespe Formation 

(Oligocene?). 

Mf217 4: Santa Barbara Formation 

(lower Pleistocene) ; silty bryozoan marl; approximately 21 ft ( 6 

m) from base of formation. 

Mf2175: Santa Barbara Formation 

(lower Pleistocene) ; silty bryozoan marl; approximately 24 ft (7 

m) above Mf2074. 

Mf2176: Santa Barbara Formation 

tion (lower Pleistocene) ; silty 

bryozoan marl; approximately 12 

ft (4 m) above Mf2075 and 12 

ft ( 4 m) below top of formation. 

Southern Pacific RR cut, 0.75 mile (1.2 km) 

northeast of Shuman, Calif. (Casmalia 

7.5' quad., 1959) where the road from 

Shuman to Santa Maria crosses RR, at 

benchmark 370; Guadalupe 7.5' quad., 

1959. Locality 170 of Woodring and 

Bramlette, 1950. (See their p. 38 and 

p. 44 for measured sections.) Foxen 

Mudstone (middle to upper Pliocene) consists of about 285 ft (87 m) of finegrained sands containing shell beds ; 

Careaga Sandstone (upner Pliocene) consists of about 290 ft ( 90 m) of mediumto coarse-grained sands containing shell 

beds. 

Mf2177: Foxen Mudstone (middle to 

upper Pliocene) ; fine sandy shell 

bed, about 95 ft (29 m) above 

base of exposure. 
STRATIGRAPHY AND AGE OF PLIOCENE AND PLEISTOCENE UNITS 29 

TABLE 6.-Register of fossil localities-Continued 

Mf2178: Foxen Mudstone (middle to 

upper Pliocene) ; fine sandy shell 

bed about 85 ft (26 m) above 

Mf2077. 

Mf2179: Careaga Sandstone, Graciosa 

Coarse-Grained Member (upper 

Pliocene); 3- to 4-ft (1-m) sandy 

shell bed about 170 ft (52 m) 

above Foxen-Careaga contact. 

Mf2180: Road cut at Fugler Point; on south side 

of road from Santa Maria to Garey, 

Calif.; Twitchell Dam 7.5' quad., 1959 

(middle of north side of sec. 35, T. 10 N., 

R. 33 W.). Locality 178 of Woodring and 

Bramlette, 1950. (See their p. 47 for 

measured section.) Careaga Sandstone 

(upper Pliocene) consists of about 50 ft 

(15 m) of fine-grained marine sands .containing shell beds, often impregnated witn 

asphalt. 

Mf2180: Careaga Sandstone, Cebada 

Fine Grained Member (upper Pliocene) ; fine-grained sandy shell bed 

about 6 ft ( 2 m) thick near base of 

exposure; containing many brachiopods and impregnated with asphalt. 

All samples · except Mf2170 collected in 1971 by Page 

Valentine and J. W. Valentine, Dept. Geology, Univ. of California, Davis, Calif.; Mf2170 was provided by J. H. Lipps 

of the same department. 

STRATIGRAPHY AND AGE OF PLIOCENE AND 

PLEISTOCENE UNITS 

SAN DIEGO FORMATION 

The San Diego Formation is exposed in the mesas 

which extend ea,stward of San Diego, Calif., and 

southward past the International Boundary. The 

formation also crops out north of Mission Bay on 

Mount Soledad and in sea cliffs at Pacific Beach. 

Hertlein and Grant (1944) provide a review of ea.rlier stratigraphic and paleontologic studies of these 

beds. 

The gently dipping San Diego Formation lies unconformably between Eocene marine sandstone below and Pliocene conglomerates and horizontal Pleistocene marine terrace deposits and nonmarine alluvium above. The formation varies in thickness 

from over 1,000 ft (300m) in the mesas to the east 

to about 400ft (120m) at Pacific Beach; lithologically, the sedi·ments range from fine-grained marine 

sands conta;ining scattered conglomeratic lenses to a 

white, sandy marl. The exposures in the north-trending cliffs at Pacific Beach, from which samples for 

the present study were collected, are the most fo-ssiliferous. Here yello-w-brown marine sands containing sheii beds are overlain by white, sandy, somewhat indurated marls. These beds lie unconformably 

on Eocene marine sandstones and are capped by 

horizontal marine terrace deposits of the Bay Point 

Formation (upper Pleistocene). 

According to Hertlein and Grant (1944), W. H. 

Dall in 187 4 first referred these sediments to the 

Pliocene on the basis of their moiiuscan fauna; Hertle,in and Grant consider the San Diego Formation to 

be o.f middle Pliocene age. Woodring and others 

(1940, p. 112) indicate (in a correlation chart) a 

probable late Pliocene age for the San Diego Formation at Pacific Beach, while considering other exposures to be early and middle Pliocene; Woodring 

(1957) stiii considered the upper part of the San 

Diego Formation (Pacific Beach) to be of late Pliocene age. J. W. Valentine (1961) cites vertebrate as 

well as invertebrate faunal evidence in assigning a 

tentative age of Pliocene and Pleistocene to the San 

Diego Formation, .and this would indicate a possible 

Pleistocene age for the Pacific Beach beds. AIIison 

( 1964) considers the formation to be probably Pleistocene on the basis of vertebrate (horse tooth) evidence. For the purposes of this report, the San 

Diego Formation at Pacific Beach is considered to be 

late Pliocene in age. 

Sample Mf2165 of this study was collected from a 

sheii bed in marine sands about 100ft (30m) above 

the Eocene-Plio-cene contact a.t Pacific Beach. Samples Mf2166 1 and Mf2167 were collected from the 

coarse sandy marls about 100ft above Mf2165 and 

somewhat above th·e middle of the exposure which is 

approximately 400ft (120m) thick at Pacific Beach. 

SAN PEDRO FORMATION AND PALOS VERDES SAND 

The San Pedro Formation and the Palos Verdes 

Sand are expo-sed in the Palos Verdes Hills, an anticlinal, coastal fault block which rises to about 1,500 

ft (460 m) in altitude on the southwest border of the 

Los Angeles basin. These units crop out chiefly on 

the north and east slopes orf the Palos Verdes Hills, 

the best ·exposures occurring in and around the city 

of San Pedro. Woodring and others (1946) made an 

exhaustive study of the geology and paleontology of 

the area; J. W. Valentine (1961) contributed paleoecologic interp,retations oi the molluscan fauna 

found in these units. The foiiowing summary of the 

st~atigraphy of these two form,ations has been taken 

in large part from these two studies. 

The gently folded San Pedro Formation is 350-

600 ft (105-180 m) thick and includes three mem1 Mf=microfossil. 
30 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

hers which have been assigned to the lower Pleistocene : the basal Lomita Marl Member, the middle 

Timms Point Silt Member, and an unnamed upper 

member ( "S.an Pedro Sand" o[ Woodring and others, 1946). The Lomita Marl Member is composed of 

60-70 ft (20m) of glauconitic sands, marls, and calcareous sands and lies unconformably on lower 

Pliocene rocks or Fernando Formation or on the 

Monterey Shale (Miocene). The age of the Lomita 

is in dispute. Woodring (1952) assigns it an ea.rly 

Pleistocene age and places the Pliocene-Pleistocene 

boundary at its base. Obradovich (1968) assigns it 

an age of 3 million years on the basis of radiometric 

dating of glauconite, and this would make it Pliocene 

according to current usage. Fanale and Schaeffer 

(1965) used helium-uranium ratios to date the 

Lomita at about 155,000 yea.rs or late Pleistocene. 

Bandy (1967) places it in the lower Pleistocene on 

the basis of foraminiferal coiling ratios; Bandy and 

Wilcoxon (1970), however, assign it to the upper 

Pleistocene on the ba;sis of planktonic foraminiferal 

and paleomagnetic stratigraphy. Zinsmeister (1970) 

correlates the upper Pliocene deposits of Newport, 

Calif., with the Lomita and cites molluscan and fish 

faunal evidence for a late Pliocene age of the Lomita. 

The San Pedro Formation is considered to be of 

early Pleistocene age in this report. 

The Timms Point Silt Member is composed of 30-

80 ft (9-24 m) of marine silts and sandy silts containing fossiliferous horizons and lies either unconformably or in gradational contact with the Lo·mita 

Marl M·ember below and the "San Pedro Sand" 

above. The Timms Point is believed to be essentially 

equivalent in age to the Lomita, but the succession 

of the two formations documents a radical change in 

the sedimentary environment. 

The "San Pedro Sand" is composed of about 175 

ft (55 m) of sands, often crosshedded, which include 

fossiliferous horizons :and beds of silt and gravel; it 

is truncated by upper Pleistoc·ene terrace deposits. 

The Palos V e·rdes Sand (upper Pleistocene) is a 

marine terrace deposit consisting of es~sentially horizontal, fos1siliferous, coa.rse sands and gravels, silty 

sands and silt. It is as much as 15ft (5 m) thick and 

lies unconformably on sediments of Miocene to 

Pleistocene age. 

Samples used in this study were collected from the 

Lomita Marl and Timm1s Point Silt M·embers (lower 

Pleistocene) , which crop out on 2d Street in San 

Pedro. The Lomita here consi·sts of about 50ft (15 

m) of marls and calcareous sands; sample Mf2168 

wa;s taken at the base of the section, and Mf2169 in 

the middle. The Timms Point was sampled in a has,al 

shell bed (Mf2171) above the burrowed contact with 

the Lomita and again 20 ft ( 6 m) above the contact 

(Mf2172). A sample (Mf2170) from the Lo·mita 

was taken near the top o[ the formation in the 

Lomita Quarry ("upper foram bed" of Galloway and 

Wissler, 1927) on the north side of the Palos Verdes 

Hills. The "San Pedro Sand" was not sa.mpled. A 

collection was also made (Mf2173) in a sandy shell 

bed of the Palos Verdes Sand (upper Pleistocene) 

which crops out in San Pedro. 

SANTA BARBARA FORMATION 

The Santa Barbara Formation is exposed near the 

coast southwest of Santa Barbara, Calif., and also at 

Rincon Point to the east of the city. It has a maximum thickne•ss of about 2,000 ft (600 m), is composed of marine :sand, silt, and clay, and lies unconformably on older Tertiary sedimentary rocks (Upson, 1951). Woodring and oth·ers (1946) and Woodring (1952, 1957) consider the Santa Barbara Formation to be correlative with the San Pedro Formation (lower Pleistoeene), and J. W. Valentine 

(1961) indicates that the Santa Barbara Formation 

and the Lomita Marl Member of the San Pedro Form,ation are equivalent in age. 

Collections were made in the lower part of the 

Santa Ba.rba.ra Formation at the Bathhouse Beach 

exposures which dip gently south and lie unconformably on the Sespe Formation (Oligocene?). The beds 

are about 70 ft (20 m) thick and comprise highly 

fossiliferous, silty, bryozoan marls. Samples Mf2174, 

Mf2175, and Mf2176 were collected in sequence from 

the lower to the upper part of the exposure. 

FOXEN MUDSTONE AND CAREAGA SANDSTONE 

The Foxen Mudstone and the Careaga Sandstone 

belong to a sequence of marine and nonmarine sediments deposited in the late Tertiary Santa Maria 

basin. These formations are exposed around and 

within the Santa Maria district, a northwest-trending lowland on the California coast north of Point 

Conception. The geography and paleontology of 

uni:bs found in the Santa Maria district have been 

described by Woodring and Bramlette (1950). 

The Foxen Mudstone is a sequence of fossiliferous 

mudstones, siltstones, and fine-grained sandstones as 

much as 800ft (245m) thick. It is conformable with 

the Sisquoc Form·ation (upper Miocene to middle 

Pliocene) below and the Careaga Sandstone above. 

On the basis of its molluscan and foraminiferal asse,mbl·ages, the Foxen has been assigned an age of 

middle to late Pliocene. The Careaga Sandstone is 
STRATIGRAPHY AND AGE OF PLIOCENE AND PLEISTOCENE UNITS 31 

composed of two members, a lower fine-grained 

sandstone of 1,000 ft (300 m) maximum thickness, 

the Cebada Fine-Grained Member, and an upper 

coarse-grained sandstone and conglomerate of 425 

ft (130 m) maximum thickness, the Graciosa 

Coa.rse~Grained Member. The formation lies conformably under the nonmarine Paso Robles Formation of Pliocene(?) and Pleistocene age. Molluscan 

fossils indicate the Careaga was deposited in late 

Pliocene time. Woodring and Bramlette (1950) correlate the Careaga with the upper part of the San 

Diego Format1ion (exposures at Pacific Beach). 

Collections for the present study we1re made in the 

upper two-thirds of the Foxen Muds.tone and in the 

Gareaga Sandstone which crops out in the Casmalia 

Hills in the western part of the Santa Maria district. 

Here about 285ft (85 m) of the Foxen and 290ft of 

the Gareaga are exposed. Samples Mf2177 and 

Mf2178 were collected in the Foxen 95 and 180 ft 

(29 and 55 m) from the bottom of the exposure. 

Sample Mf2179 was collected in the Careaga (Graciosa Coarse-Grained Member) 170 ft (52 m) above 

the Foxen-Careaga contact. An additional collection 

(Mf2180) was made in the Gareaga (Cebada FineGrained Member) at Fugler Point on the northeastern edge of the Santa Maria district. 

COMPARISON OF HOLOCENE AND FOSSIL 

ASSEMBLAGES 

FAUNAL COMPOSITION OF FOSSIL UNITS 

The Holocene fauna treated in this study comprises 50 genera; o.f these, 38 also occur in the Pliocene and Pleistocene units. Six genera occur only as 

fossils (tables 3, 4). 

The 12 Holocene genera which are not represented 

in the Pliocene and Pleistocene are principally those 

occurring along the coast north or south of the fossil 

localities which are situated in the Californian province from San Diego to just north of Point 

Conception. Bythoceratina, Costa?, Eucytherura, 

H emicythere ?, "Loxoconcha.," Orion ina, Pterygocythereis ?, "Trachyleberis," two of the three species 

of Puriana, and one of two species of Cytherella 

occur only in the Surian or Panamanian province; 

N eocaudites? occurs south of San Diego; and H emicythere occurs only in the Oregonian province. One 

·species in particular, Puriana pacifica, does not occur in fossil assemblages, although it ranges from 

the Panamanian province north to just south of 

Point Piedras Blancas at the Californian-Oregonian 

boundary and is a ubiquitous element of the Holocene assemblages in this area. Cativella sp. A is another con1mon Holocene species which is not found 

in the fossil assemblages although it ranges from 

the northern Sudan subprovince to just south of 

Point Piedras Blancas. The absence of these two 

species as fossils may be due to collecting bias, but 

the richness of the fossil deposits, especially the 

Lomita Marl Member of the San Pedro Formation 

and the Santa Barbara Formation, make this unlikely. Perhaps these species have migrated northward, at least into the shelf areas off San Pedro and 

Santa Barbara, since the early Pleistocene. The solution o.f this problem will have to wait until fossil 

ostracode assemblages along the coast become better 

known; then it will be feasible to determine movements of species along the shelf through time and 

possibly to identify the origin of new elements of 

the fauna. 

Paleoecological interpretations o.f fossil units commonly rely on comparisons of living and fossil assemblages. One must ~ssume, of course, that fossil 

representatives of a species had environmental tolerances or limits similar to those of the modern representatives of that species. Of the 123 s.pecies occurring in fossil unit1s that are included in this investigation, only 19 are not living today; 85 percent of 

the Pliocene and Pleistocene assemblages under 

study is extant and forms a broad data base. 

Table 7 indicate!s that practically th·e entire assemblage of each unit is composed o.f species living today. Older units generally contain greater percent-

-ages of extinct species, except for the Careaga Sandstone. This unit yielded the smallest fauna (27 species) and contains the most extinct species ( 6). Discovery of seve.ral of t:he fossil species in the Holocene would markedly increase the percentage of the 

Carea.ga fauna having living representatives, and it 

is probable that several of the "extinct" species exist 

today but have not yet been found in Holocene 

samples. 

CLUSTER ANALYSIS OF HOLOCENE AND 

FOSSIL SAMPLES 

The fossil and the Holocene shelf samples were 

subjected to a cluster analysis similar to that performed on the Holocene samples alone. It has been 

emphasized that faunal ass·emblages and provinces 

change character through time in response to evolutionary and migratory events and to the influences 

of climatic variations and therefore cannot be replicated, but it still is possible to compare asse1mbla.ges 

of differing age and obtain an indication of the distance in time and environment ;separating them. An 

affinity to modern faunal provinces will provide a 

qualitative me•a.sure of the marine climate which 
32 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

TAI!LE 7:-FfLunal diversity, generic and specific, of each fos- . ml umt f!nd the percentage of the fauna having living representatwes 

Formation 

Fossil PerSamples Genera . species Fossil Total centage (age) m Holo- only species of fauna cene extant 

Foxen Mudstone Mf2177, 24 

(middle to late Mf2178 

35 4 39 90 

Pliocene). 

Careaga Sandstone Mf2179, 22 21 6 27 77 (late Pliocene). Mf2180 

San Diego Forma- Mf2165, 26 56 4 60 93 tion (late Plio- Mf2166, cene). Mf2167 

Lomita Marl Mem- Mf2168, 31 68 5 73 93 her of San Pedro Mf 2169, Formation (early Mf 2170 

Pleistocene). 

Timms Point Silt Mf2171, 20 28 2 30 93 Member of San Mf2172 

Pedro Formation 

(early Pleistocene). 

Santa Barbara Mf2174, 25 48 5 53 91 

Formation (early Mf2175, 

Pleistocene) . Mf2176 

Palos Verdes Sand Mf2173 20 

(late Pleisto39 0 39 100 

cene). 

prevailed during deposition of the fossil unit. 

This analysis was based on 16 fossil samples and 

105 Holocene 15-minute samples (006-110). The 15-

minute samples located in the Panamanian province, 

and the 15 s.pecies which occur almost exclusively in 

these samples, were deleted fro·m the analysis to accommodate 19 species that occur only as fossils. The 

deleted samples are clearly different from the other 

Holocene samples (fig. 8). The deletion of the 15 

Holocene species allowed the data matrix to remain 

sufficiently small, and it was felt that inclusion of 

these species would not have altered the results of 

the cluster analysis, as the fossil samples are obviously most similar to samples occurring north of the 

Panamanian province. (See table 3 for alphabetical 

list of ostracode species included in cluster 

analyses). 

The results of the analysis are illustrated in the 

dendro·gram of figure 10. The fossil samples are 

most .similar to samples from the southern Californian subprovince, the Californian province, and the 

combined Galifornian-Oregonian provinces, in that 

order. The assembla.ges from south of Point Conception (San Diego Formation, Lomita Marl and Timms 

Point Silt Members of San Pedro Formation, Palos 

Verdes Sand, and Santa Barbara Formation) indicake a similarity to those of the Californian province, 

whereas asse·mblages from the Santa Maria district ' to the north, (Foxen Muds.tone and Careaga Sandstone) show a relationship to both the Californian 

and Oregonian provinces. This cluster pattern corroborates other ·evidence, which will be discussed 

later, regarding the marine temperatures prevailing 

during deposition of these units. 

It is doubtful that age plays a significant role in 

determining the affinities between fossil and Holocene ass-emblages, as most species have living representatives. Age is a factor only insofar as it is expressed in altered climatic conditions and corresponding changes in the composition of assemblages. 

PALEOTEMPERATURE DETERMINATIONS BASED ON 

ZOOGEOGRAPHIC EVIDENCE 

The determination of yearly marine paleotemperature ranges is based on interpretation of temperature ranges of Holocene species that occur in fossil 

units. As a first approximation, one might simply 

plot these ranges and infer that the area of overlap 

of temperature ranges of cryophiles versus thermophiles represented the possible maximum yearly 

temperature range and the endpoints the maximum 

and minimum yearly temperatures. This procedure 

is based on the assumption that the temperature tolerances determ.ined for Holocene species represent 

the maximum and minimum temperatures at which 

they can survive. However, Hutchins (1947) has 

pointed out that the distributions of marine organisms are limited by temperature in at least two ways. 

Survival temperatures (minimum and maximum) 

encompasiS the widest temperature range within 

which a species may live. A narrower range is 

bounded by the maximum and minimum temperatures required by the organism for repopulation, 

which includes reproduction and larval development. 

With regard to the geographic distribution of a 

species, the minimum survival t·emperature would 

occur poleward during the winter, and the minimum 

temperature required for repopulation would occur 

poleward in the summer (that is, the water must 

warm up enough to allow repopulation to occur). 

The maximum survival tempe,rature occurs equatorward during the summer, and the maximum temperature required for repopulation occurs equato~rward in the winter (that is, the water must be cool 

enough to allow repopulation to occur). As each specie~s may be limited at each end of its geographic 

range by only one of the two types o.f temperature 

limits, four types of species distribution or zonation 

were established by Hutchins (1947). 

Zonal type 

Poleward 

temperature limits 

1. winter survival 

2. summer repopulation 

3. summer repopulation 

4. winter survival 

Equatorward 

temperature limits 

summer survival 

winter repopulation 

summer survival 

winter repopulation 
CJ) 

0:: 

w 

ID 

::E 

::::> 

z 

w 

...J 

Q.. 

::E 

<( 

(/) 

w 

I-

:> 

z 

::E 

.n 

PALEOTEMPERATURE' DETERMINATIONS 

OTSUKA COEFFICIENT OF SIMILARITY 

100 

Cape Flattery ~ 108 

48°24' :~ 

105 

104 

103 

102 

101 

100 

99 

98 97 

96 

95 

94 

93 

92 

~ 

I 

90 80 70 60 50 40 I t I t I 

North.ern subprovince 

89 

88 

87 

86 

85 

84 

83 

82 

79 

81 

80 

78 

77 

76 

75 

74 73 

72 

71 

Ore onian province A 

Salt Point ~ ~g 38°34' ~ 

66 

65 

64 

63 

62 61 

60 59 

Southern subprovince 

Pt. Piedras 

35°40' 

Blancas ~ 55 ~ ~ -~--~ 

Pt. Conception ~~ Northern supprovince 

34°30' ~ 52 -------,: 

N. Channel Is. ~ ~5 

34°00' ~ 

47 

46 

45 

44 

43 

42 

41 

40 39 

38 

37 

36 

35 

34 

33 32 31 

Californian B 

Southern 

subprovince 

Lomita Marl ~ 

Member of S~n 121 ~~ l:3 Pedro Formation Mf2169====~===}----J E Palos Verde~ Sand---..::Mggg _____________ __J 

:;( Timms Point Silt San Di~go {~m~~--------1---------' 

g Member of San Formation ~m~l-----------~ 

Bi Format1on Mf2176 

V) Foxen Mudstone M;~~~~-----------------, 

~ 

30 20 I I 

10 

Pedro Formation Santa Barb~ra ~M~~l~~=======l----_j 1--------' 

Careaga Sandstone M~~~~------------------....J Mf2172-------------------------~l 

Timms Point Silt ~ 27 

Member of San /r 2g Pedro Formation Bahia S. Vizcaino ~4 28°15' ~~ · Punta Eugenia ~ --1--------, 

2J052' 19 ~--___J 

18 

17 16 

Cabo San Lazaro ~ 15 ___ ___J 

H 10 

9 

8 

Northern subprovince 

Surian province C 

24°48' lil 

Cabo San Lucas~ ~----_J Southern subprovince 

22°52' ~~6 ======:1----J 

100 90 80 70 60 50 40 30 20 10 

33 

0 

0 

FIGURE 10.-Dendrogram of Holocene and fossil sample clusters. Samples are compared on the basis of their ostracode species composition using the Otsuka similarity coefficient ( C IV N1N2) X 100; clustering was by the unweighted pair-group 

method. 
34 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

That species can be limited in their distribution 

by temperature tolerances other than maximum and 

minimum survival temperatures introduces complexity into the interpretation of paleotemperature. 

Inferences are even more uncertain if the type of 

zonation represented by any given species cannot be 

deterrmined. Hutchins (1947) shows that zonal type 

may be determined for a species that occurs along 

more than one coast by comparing winter and summer temperature minima and maxima at its range 

endpoints. Hazel (1970) has successfully ascertained 

the zonal type for many amphiatlantic ostracode 

species. 

Where the types of zonation represented by species cannot be dete,rmined, one does not know whether the temperatures controlling species distribution 

are survival limits or repopulation limits or both. 

Both cryophiles and thermophiles may occur in the 

same fos,sil deposit, and when the temperature 

ranges of living representatives of these species are 

compared, they usually overlap. The range of overlap and the bounds of this range are of interest in 

determining the pos~sible maximum and minimum 

paleotemperatures which occurr·ed during deposition 

of the fossil unit. There a,re four kinds of temperature limit involved where thermophiles and cryophiles approach each other and overlap in temperature tolerances: for the cryophile there are two temperature limits, summer survival and winter repopulation; for the thermophile there are two possible 

limits, winter survival and summer repopulation. 

Although we cannot always identify the nature of 

these temperature limits, it is still of interest to 

know the pos·sibilities that the limits represent survival maxima and minima and therefore convey the 

temperature limits that could have occurred at a 

fossil locality. 

In the following model, the temperature ranges of 

a pair of species, one thermophile and one cryophile, 

are allowed to approach each other and overlap. The 

possible interactions of the temperature limitations 

are illustrated in figure 11. Thirteen configurations 

occur, 7 of which are impossible owing to constraints 

applied by the survival and the repopulation temperature tolerances of one or both of the two species. 

For ·exa.mple, two species can occur together only if 

the repopulation temperature limits are equal to or 

lie within the survival tolerances. Obviously, two 

specie's cannot coexist if the te,mpe·rature needed for 

repopulation by one lies above the maximum or below the minimum survival temperatures of the other 

species. 

For each of the six configurations in which a cryophile and a thermophile can coexist, there are four 

subcases. The first subcase involves the situation 

where the cryophile is limited by a summer survival 

temperature and the thermophile is limited by a 

winter survival temperature (fig. 11, configuration 

11A). This temperature overlap then incorporates a 

possible maximum and minimum ye,arly temperature 

which would be defined if this situation could b~ 

identified in a fossil unit. The other three subcases 

involve two situations in which one of the species is 

limited by survival temp·eratures and the other by 

repopulation tempe,ratures, and a third situation in 

which both a.re limited by repopulation temperatures 

(fig. 11, configurations 11B, C, D). Of the 

24 possible subcases, 4 involve temperature range 

disjunctions. 

In practice, when the temperature ranges of a 

cryophile and a thermophile are being compared, the 

overlapping temperature range ·endpoints represent, 

respectively, the maximum summ-er temperature and 

the minimum winter temperature they experience in 

their geographic distribution. Now, we do not know 

whether these temperatures actually represent summer survival maxima and winter survival minima or 

whether the particula~r species are limited by repopulation temperatures inside these limits. If all 

temperature limits in 15 theoretical subcases are 

counted (excluding four subcases of disjunct temperature ranges, and five subcases of coincident temperature endpoint1s), 10 of the 15 possible upper 

temperature limits are real survival maxima and 5 

are repopulation limits; all these are ·upper limits 

exhibited by cryophiles (that is, the real survival 

maxima are summer survival temperatures of cryophiles). And 10 of the 15 possible lower temperature 

limits are real winter survival minima of thermophiles. In this model, therefore, 67 percent of the 

maxima and minima represented by overlapping 

temperature ranges of pairs of cryophiles and thermophiles are survival temperatures and should outline the possible yearly maxima and minima. 

When subc,ases involving disjunct temperature 

ranges are considered, there are four minima and 

four maxima, and two of each are real survival maxima and minima. When temperature range endpoints 

of a cryophile and a thermophile are coincident (five 

subcasers) , 40 percent always represent survival 

maxima of the cryophile, 40 percent represent survival minima of the thermophile, and 20 percent 

represent repopulation boundaries. Their relationship to pairs o.f overlapping temperature ranges 

should indicate which they are. 
PALEOTEMPERATURE DETERMINATIONS 35 

TEMPERATURE 

CONFIGURATION COOL WARM 

1 E1 0 TEMPERATURE LIMITS 

• • l0 Summer survival CRYOPHILE 

E1 0 EJ Winter repopulation 

2 • • THERM·j· Winter survival 

OPHILE • Summer repopulation 

E1 0 3 ~ Survival temperature 

• • ~ limiting 

w ~- Repopulation temperature ...J -<) limiting (II El 0 4 u; 

CJ) • • 0 

a.. 

::?i 

-

5 E1 0 

• • 

[] 0 6 • • 

EJ 0 7 

---------- --- • • -------------------------------------- EJ 0 8 • • 

EJ 0 9 • • 

D 0 8 E1 0 10 w • • ·----· ...J 

(II 

u; 

CJ) 

c ----[]-----0 0 A D 0 11 a.. 

• • • • 

E1 0 D ----CJ------0 12 • • ·---

. 

El 0 13 • • 

FIGURE H.-Interactions of temperature limits (survival and repopulation) of a cryophile and a thermophile. Configurations 

1-7 cannot occur because of constraints applied by temperature limits of one or both species. Configuration 11 is expanded 

to include four subcases. See text for further explanation. 
36 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

The purpos·e of all this discussion is to establish a 

basis for the interpretation of temperature range 

overlaps of Holocene species occurring together in 

fossil deposits. (For examples, see figs. 12, 14-19). 

It may be noted that the species do not have to actually occur together in the Holocene-and depending 

on the configuration of the marine isotherms they 

may not-but theoretically they must be able to coexist in some thermal regime. The temperature 

ranges of species occurring as fossils usually overlap each other in a stepwise manner, each step including many species. It would s·eem from the foregoing discussion that about two-thirds of the temperature range endpoints of cryophiles could represent actual summer survival maxima, and that a 

similar percentage of the temperature range endpoints of thermophiles could represent actual winter 

survival minima, thus outlining the yearly temperature maxima and minima that could occur at that 

locality and still allow the speci·es to coexist. If two 

steps of temperature range endpoints, each for cryophiles and thermophiles, are allowed to delineate the 

temperature rang.e, there would be a good chance of 

including actual maxima and minima. In this case, 

the possible yearly minimum and maximum paleotemperatures would bound a wider temperature 

range than might actually have occurred. 

An important constraint must be placed on this 

technique. We have assumed until now that the occurrence of each of the species zonal types is equally 

probable. This may not be a valid assumption in all 

situa.tions. For example, northward-ranging thermophiles may be limited by a sum.mer temperature 

which has to reach a certain value to allow repopulation to occur. In this case many of the geographic 

range endpoints of thermophiles woul~ be attributable to summ·er repopulaticn limits and not winter 

survival minima. Consequently, the inferred possible yearly minimum paleotemperature would be 

higher and the possible yearly paleotemperature 

range narrower than if there were random occurrence of species zonal types. Of course, if the zonation type of certain species can be ascertained, the 

above procedure can be simplified and more 

confidence placed in the inferred yearly paleotemperatures. 

The paleotemperatures of southern California fossil assemblages, which are discussed in the subsequent section, were determined using the method [ 

outlined above. 1 

PALEOCLIMATIC IMPLICATIONS OF FOSSIL 

ASSEMBLAGES FROM SOUTHERN CALIFORNIA 

A common assumption in paleoclimatic analyses 

of fossil assemblages is that fossil represenbatives of 

a s.pecies had environmental tolerances similar to 

those of the living representatives of the species. 

With progressively older faunas, fewer species or 

even genera are living, and confidence in analyses 

based only on this assumption rapidly decreases. Recent zoogeographic studies dealing with marine 

paleotemperatures of the eastern Pacific which review earlier work and provide new interpretations 

include reports by J. W. Valentine (1961), J. W. 

Valentine and Meade (1961), Addicott (1966), and 

Kern (1973). 

The following dis.cussion incorporates information 

from the literature (mainly molluscan and foraminiferal studies) with new evidence, principally regarding ma;rine tem.pera;tures, deriv·ed from investigations on the Ostracoda. The temperature toleranc·es 

of Holo·cene ostracode species w·ere developed by 

comparing their distribution to marine temperature 

maps (figs. 6, 7) . Two sets of maps were used, one 

based on -1 O~m temperatures along the coasts of 

Baja California and California to San Francisco 

(Lynn, 1967) and the other based on surface temperatures from San Francisco to Cape Flattery 

(Robinson, 1957). The data presented by Lynn are 

considered to be the more accurate in reflecting bottom temperatures, and fortunately his maps cover 

the areas most critical to this report. The temperature tolerances of all ostracode species ranging 

through at least 2° of latitude were us·ed in the p.aleotemp·erature determinations, and the number of species employed varied from 19 to 55 depending on the 

fossil unit involved. Species from all samples of a 

particul~ar formation we,re combined in determining 

the paleotemperature range of that unit ( determinations based on sepa.rat.e samples gave similar results) . Depth ranges of ostracode species in the 

study area are not yet known, so that depth determinations ·are based on previous interpretations of 

othe1r organisms. 

SAN DIEGO FORMATION 

The San Diego Formation at Pacific Beach, of late 

Pliocene age, is inferred to represent a depositional 

environment no deeper than 300 m (Hertlein and 

Grant, 1944). The samples from Pacific Beach are 

indicative of two different environments of deposition. S.ample Mf2165 was collected in terrigenous 

sands containing scattered shell beds typical of an 
PALEOCLIMATIC IMPLICATIONS OF FOSSIL ASSEMBLAGES 37 

open shelf environment. Samples Mf2166 and 

Mf2167, on the other hand, were collected in coarse 

sandy marls indicative of an environment receiving 

little ino,rganic debris from rivers and coastal erosion processes. Highly calcareous sediments are 

known to be presently accumulating off the eastern 

(leeward) shore of Santa Catalina Island (Shephard 

and Wrath, 1937), while the windward shelf exhibits chiefly terrigenous s·ediments. The three samples from the San Diego Formation cluster together 

(fig. 10) ; the assemblages from the calcareous sediments show more affinity for each other and may 

reflect habitat similarity. Together these assemblages cluster with the combined subprovinces of the 

Californian province, in spite of the fact that the 

San Diego Formation lies on the coa,st well within 

the limits of the southern California subprovince. 

A comparison of the present temperature tolerances of 46 os:6racode sp·ecies from the San Diego 

Formation (figs. 12, 13) shows that the marine te·mperatures could have ranged from 14° to 18° C, no 

different from the marine temperatures off that part 

of the coast today (figs. 6, 7). The cluster analysis 

shows, however, that the Pliocene and modern ass~emblages at that latitude are different, probably 

the result of a change in the overa.ll clim,atic regime· 

not apparent in the marine temperatures at that 

Point, but reflected in the range of specie's responding to the change. 

FOXEN MUDSTONE AND CAREAGA SANDSTONE 

In the Santa Maria district, the Foxen Mudstone 

(middle to upp'e'r Pliocene) contains molluscan and 

foraminiferal assemblages which suggest deposition 

in an inner sublittoral marine environment (50 m 

maximum depth); molluscan evidence indicates the 

Oareaga Sandstone (upper Pliocene) was deposited 

in shallow water (to about 30-60 m) (Woodring and 

Bramlette, 1950). On the basis of inferences from 

foraminifers, Natland (1957) also regards both 

units to represent inner sublittoral depths. The ostracode collections are from fine sands and sandy 

shell beds suggestive o[ an open shelf environment. 

The Foxen and Ca.reaga samples cluster together 

but a.t relatively low values, possibly indicating 

somewhat different habitats. These samples cluster 

at a low leve'l with the Californian province; in fact 

they show only slightly more affinity for the Californian P'rovince than do the Californian and Oregonian provinces for each other (fig. 10). This low 

correlation is clea.rly due to the presence of northern 

elements in these fossil assemblages. 

The Santa Maria district lies on the coast within 

the modern northern Californian subP"rovince. The 

water te,mperatures along this part of the coast annually rang.e from 12° to 15° C. Natland (1957) inferred, on the basis of foraminiferal as,semblages, 

temperatures ranging from 8° to 13° C for the upper 

part of the Foxen Mudstone, and from 13 o to 15 o C 

for the Careaga Sandstone. Thirty-two ostracode 

species from the Foxen (figs. 13, 14) and 19 species 

from the Careaga (figs. 13, 15) indicate the yearly 

temperatures could have ranged from 12° to 15° C. 

These results agree with those of Natland (1957) for 

the Gareaga and a:re identical with present marine 

temperatures off that coast (figs. 6, 7). 

LOMITA MARL AND TIMMS POINT SILT MEMBERS 

OF THE SAN PEDRO FORMATION 

The Lomit,a Marl and Timms Point Silt Members 

of the San Pedro Formation at San Pedro are of 

early Pleistocene age. Though closely associated in 

time, they represent two radically different sedimentary environments which are similar to thos.e of 

the San Diego Formation at Pacific Beach. Studies 

of the mollus·can fauna by Woodring and others 

(1946) and J. W. Valentine (1961) indicate shoaling towards the top of the Lomita; the lower beds 

of the Lomita represent the outer sublittoral (deeper than 100 m) whereas the upper beds generally 

represent depths of 50-100 m. Molluscan evidence 

indicates that the Lomita was deposited on the lee 

side of an offshore island in a sedimentary environment notably low in te,rrigenous detritus; the water 

temperature at the time o:f deposition was similar to 

that in the region today, except that the outer sublittoral was probably cooler. 

The mollusks of the Timms Point Silt Membe.r 

represent an outer sublittoral association (100-200 

m), equivalent in depth to the lower part of the 

Lomita. The sedimentary regime was radically different, however, since the Timms Point, in contrast 

to the Lomita, is c.ompos,ed almost entirely of terrigenous sediments. These sediments resemble the silts 

and sandy silts which are at present derived from 

the Coast Ranges and being deposited on large areas 

of the continental shelf. The molluscan fauna represents a marine climate somewhat cooler than that of 

the region today. 

The ostracode genus Perissocytheridea occurs as a 

minor constituent of the Lomita and Timms Point 

assemblages. This genus lives in shallow, brackish to 

normal marine environments. During this study it 
38 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

SPECIES 

28-29 

27-28 

SAN DIEGO FORMATION 

26-27 

25-26 

24-25 

23-24 

22-23 

21-22 

20-21 

19-20 

18-19 

18 

17-18 

16-17 

15-16 

14-15 

14 

13-14 

12-13 

11-12 

10-11 

9-10 

8-9 

7-8 

6-7 

5-6 

FIGURE 12.-Modern temperature tolerances for 46 ostracode species that occur in the San Diego Formation (upper Pliocene); inferred possible yearly minimum and maximum paleotemperatures, to the nearest 1 oc are 14° and 18°, as 

indicated by the patterning. See table 4 for numerical list of ostracode species. 

was found to occur only in samples from shallow 

depths (usually 20m or less) seaward of harbor entrances. Although Perissocytheridea may be a transported element in the fossil assemblages, it indicates 

proximity to a bay or estuary. 

Molluscan studies show that the assemblages from 

the Lomita and Timms Point are not equivalent. The 

cluster analysis (fig. 10) based on ostracode samples also indicates that the ass.emblages are different; the Lomita samples cluster with the southern 

Californian subprovince, whereas the Timms Point 

sample shows more affinity to samples from the Santa Barbara Formation which, in turn, cluster with 

the Californian province. Sample Mf2172 from the 
PALEOCLIMATIC IMPLICATIONS OF FOSSIL ASSEMBLAGES 39 

Yearly range of inner sublittoral bottom 

Time Faunal (sub) province Latitude temperature to nearest 1 o C Marine climate 

north 5 10 15 20 25 30 

--------- ? 48°24' - ...L'...!..!.. :!....,! T T • ~ .!..'...!.. _!_ '...!.!... !..'..!..'- ~ ~-----

OREGONIAN 

N 

- 38°30' f-

~ ~ Mild temperate 

s 

35°30' 

~ 

N ~ ~~ CALIFORNIAN /~ Warm - 34°00' 1-

Holocene s ~ ~~ ~ temperate 

:%: 

28°15' 

N ~~ ~ ~ SURIAN - 24°45'- Subtropical 

s ~ ~~ ~l 22°45' 

PANAMANIAN ~ ~ -~~ Tropical 

----------- '·~-- ~-- ---~-- ---~-----

Fossil unit 

Holocene ~ 

Late PI iocene Careaga Sandstone 34°54' ~ Warm 

Middle to late ~ 

temperate 

Pliocene Foxen Mudstone 

Holocene ~ ~ 34°25' 

Warm 

Early Pleistocene Santa Barbara Formation ~ ~ temperate 

Holocene ~ ;:::; 

Late Pleistocene Palos Verdes Sand ;%0 

~ -

~ Warm 

San Pedro Formation 33°44' temperate Early Pleistocene Timms Point Silt Member ~ 

Early Pleistocene Lomita Marl Member /.::C,; 

~ -

-

Holocene ~ 32°48' 

- Warm 

Late Pliocene San Diego Formation ~ 1P~ temperate 

I I I I I I I I I 

FIGURE 13.-Yearly marine temperature to the nearest 1 o C occurring in the ostracode faunal provinces of the easttern Pacific shelf; and possible yearly temperature ranges in fossil units of southern California inferred from 

ostracode species distributions. 

Timms Point contains a very small assemblage and, 

consequently, shows little similarity to other fossil 

and Holocene samples; it is disregarded in paleo,ecological interpretations. The dissimilarity between 

the Lomita and Timms Point samples may be due to 

differences in habitat represented by the two units. 

A determination of temperature tolerances of 19 

ostracode species of the Timms Point indicates that 

the yearly temperatures could have ranged from 13° 

to 18° C (figs. 13, 16), identical to water temperatures determined for the Lo·mita (figs. 13, 17; based 

on 55 species) and ve·ry similar to those prevailing 

off the coast today (figs. 6, 7). 

J. W. Valentine and Meade (1961, table 12) determined paleotemperatures for these two units at San 

Pedro based on zoogeographic as w·ell as oxygen isotope temperature techniques. The zoogeographic evidence yields paleotemperatures ranging from 11 o to 
40 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

SPECIES 

~ ~ ~ ~ ~.... N ~ ~ ~ N ~ 00 ~ 0 ~ ~ N V 0 ~ 00 0 v ~ 0 ~ ~ 00 Ol 00 Ol Ol 

oc ..... ~_..:£._8 ...... 8 ......... 1o...j~ ... ~ ...... 8 ..... ~~~ ...... ~ ..... ~-~ .... ::: ....... ::: ..... ~l....j8.._ .. 8..... t:i ..... ~ .... ~ ....... ~ .... ~....,jo.._~ ....... :::....,j~ .... 8 ....... t:i..... g....,j~._::: ..... 

28-29 

FOXEN MUDSTONE 

27-28 

26-27 

25-26 

17-18 

16-17 

15-16 

14-15 

13-14 

12-13 

11-12 

10-11 

9-10 

8-9 

7-8 I I I I I I I I I I I I 

• I I I I I I I I I I I 

6-7 

5-6 

15 

12 

FIGURE 14.-Modern temperature tolerances for 32 ostracode species that occur in the Foxen Mudstone (middle to upper Pliocene); inferred possible yearly minimum and maximum paleotemperatures, to the nearest 1 o C, are 12° and 15o C, as indicated by the patterning. See table 4 for numerical list of ostracode species. 
PALEOCLIMATIC IMPLICATIONS OF FOSSIL ASSEMBLAGES 41 

SPECIES 

r-...OOC\I.-tfl)000\fl)fl)0'<tO.-tor-...r-... 000'1 

oc ... ~ ...... t:l .... ~ ..... ~ .... ~ ... ~ ...... ~ .... ~~::: .... ::: ... 8._ ... ~ .... ~ ..... ~~....~ ... ............. ~ ~ ........... 

28-29 

27-28 

26-27 

25-26 

24-25 

23-24 

22-23 

21-22 

20-21 

19-20 

18-19 

17-18 

16-17 

15-16 

14-15 

13-14 

12-13 

11-12 

10-11 

9-10 

8-9 

7-8 

6-7 

5-6 

CAREAGA SANDSTONE 

• I • I 

I 

I 

FIGURE 15.-Modern temperature tolerances for 19 ostracode 

iSpecies that occur in the Careaga Sandstone (upper Pliocene); inferred possible yearly minimum and maximum 

paleotemperatures, to the nearest 1 o C, are 12o and 15° C, 

as indicated by the patterning. See table 4 for numerical 

list of ostracode species. 

SPECIES 

28-29 

TIMMS POINT SILT 

27-28 MEMBER OF SAN PEDRO FORMATION 

26-27 

25-26 

24-25 

23-24 

22-23 

21-22 

20-21 

19-20 

18-19 

18 

l7-18 

16-17 

15-16 

L4-15 

L3-14 

13 

l2-13 

l1-12 

.0-11 

9-10 

8-9 

7-8 

6-7 

5-6 

FIGURE 16.-Modern temperature tolerances for 19 ostracode 

species that occuT in the Timms Point Silt Member of the 

San Pedro Formation (lower Pleistocene) ; inferred possible 

yearly minimum and maximum paleotemperatures, to the 

nearest 1 o C, are 13° and 18° C, as indicated by the patterning. See table 4 for numerical list of ostracode species. 
42 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

SPECIES 

28-29 

27-28 LOMITA MARL MEMBER OF SAN PEDRO FORMATION 

26-27 

25-26 

24-25 

23-24 

22-23 

21-22 

20-21 

19-20 

18-19 

17-18 

16-17 

15-16 

14-15 

13-14 

12-13 

11-12 

10-11 

9-10 

8-9 

7-8 

6-7 

5-6 

I I 

I I 

I I 

I I 

18 

13 

FIGURE 17.-Modern temperature tolerances for 55 ostracode species that occur in the Lomita Marl Member of the San 

Pedro Formation (lower Pleistocene); inferred possible yearly minimum and maximum paleotemperatures, to the 

nearest 1 o C, are 13° and 18° C, as indicated by the patterning. See table 4 for numerical list of ostracode species. 

21 o C for the Lomita. The molluscan temperature 

tolerances were determined by these authors from 

marine tempe,rature data that have since been revised. Regarding the Lomita, their 21 o C temperature was believed to be the minimum temperature 

experienced by Panamanian forms (which occur in 

the Lomita) at Cabo 8an Lucas. According to the 

latest data (Lynn, 1967; fig. 6), this temperature 

should be revised to 18° C; the paleotemperature 

range of 11 o to 18 o C is more in line with the results 

of the present study (13° to 18° C). Isotopic temperatures from the Lomita fossils range from at 

least 13.2° to 19.0° C, also in agreement with paleotemperatures based on ostracode tolerances. Paleotemperatures for the Timms Point (J. W. Valentine 

and Meade, 1961) based on the molluscan distributions range from 11 o to 14 o C and based on isotopic 

analyses from 5.7° to 13.8° C. These temperatures 

are below the range of 13° to 18° C dete,rmined from 

ostracode distributions and may reflect the deepe.r 

environment of deposition indicated by the mollusc,an assemblages of the Timms Point. 

SANTA BARBARA FORMATION 

The Santa Barbara Formation is correlative with 

the Lo·mita Marl Member (lower Pleistocene) ; it is 

richly fossiliferous, especially in the lower part, and 

the molluscan fauna has been partially documented. 
DISCUSSION 43 

(See references in J. W. Valentine, 1961; Woodring 

and others, 1946.) These molluscan assemblages are 

interpreted to represent inner sublittoral depths in 

the lower part of the unit, whereas the fauna of the 

upper beds is indicative of somewhat deeper conditions. Samples for this study were collected in the 

bryozoan marls in the lower part of the formation at 

the Bathhouse Beach locality. J. W. Valentine 

(1961) interpreted the molluscan assemblages here 

to be indicative of depths between 30 and 70 m. Bullivant (1969) examined the same beds, and on the 

basis of their faunal and lithological character interpreted them to represent an offshore bioherm deposited at 40-60 m in a marine climate similar to or 

perhaps a little coole,r than that found offshore today. 

The Santa Barbara samples cluster with those of 

the Californian province at a low level but not as 

low as the Foxen and Careaga samples (fig. 10), 

which have a more northern aspect. Paleotemperatures of the Santa Barbara Formation (figs. 13, 18; 

based on 36 ostracode species) could have ranged 

from 13° to 18° C, similar to water temperatures 

found off that coast today (figs. 6, 7). 

PALOS VERDES SAND 

The Palos Verdes Sand at San Pedro is of late 

Pleistocene age. The molluscan fauna is indicative 

of an inner sublittoral habitat. The ostracode assemblage is distinctive, as can be seen in the cluster 

analysis (fig. 10) ; the sample clusters with no other 

fossil sample and shows similarity to samples of the 

Californian province. Temperature tolerances of 31 

ostracode species of the Pal_os Verdes Sand indicate 

that the yearly temperatures could have ranged from 

13° to 18° C (figs. 13, 19), equivalent to the present 

annual temperature range off that coast (figs. 6, 7). 

J. W. Valentine and Meade (1961) have also calculated paleotemperatures for this unit. The molluscan temperature tolerances indicate a range from 

14 o to 21 o C, and the isotopic analyses give a temperature range from at least 12.3° to 18.2° C. If, as 

explained during discussion of the Lomita Marl 

Member above, the 21 o C te·mpe·rature is lowered to 

18o C to reflect the latest marine temperature studies, then Valentine and Meade's determinations 

agree well with thos'e based on ostracode temperature tolerances. 

DISCUSSION 

The marine climates prevailing during deposition 

of the Pliocene and Pleistocene units treated here 

were probably not very different from those existing 

today off those sites. That the Holocene and fossil 

assemblag,es in those areas do not show a strong r~ 

semblance, although most species occurring as fossils have living representatives, leads one to believe 

that the ma.rine climate off southern California has 

indeed changed, even though the change is not easily 

detectable in the paleo,temperature determinations 

for particular localities. This situation is understandable, even expected, in view of the complex systems involved as well as the fragmentary nature of 

the climatic record. 

The basic patterns of faunal distribution existing 

on the shelf can be attributed to the interaction of 

two very complex systems. One is the marine climatic system, simplistically expressed in the configuration of marine isotherms ; the other is a system 

of ecological units ranging in organizational complexity from the individual organism to the provincial assemblage. 

Both systems alt·er their character very gradually. 

The marine climate is, in fact, a highly buffered system, and direetional changes in the properties and 

effects of atmospheric wind systems, oceanic current 

patterns, solar radiation, and other major and minor 

environmental determinants are required to modify 

the climatic regime. Modifications that are of interest here would include alteration of annual water 

temperature ranges and the appearance of new isothermic configurations. Isotherms probably would 

riot merely shift position along the coast in concert; 

movement might take place in some areas and not in 

others, and bunching and dispersion of isotherms 

would also occur, producing new thermal gradients 

and dissipating others. The magnitude and duration 

of the,rmal barriers might change. Climatic alteration would not necessarily have to be great to influence considerably the distribution of marine 

organisms. 

Individual org,anisms, populations, communities, 

and provincial assemblages together form another 

highly complex system, each ecological unit or component of the system responding somewhat differently to environmental stimuli (J. W. Valentine, 1968, 

1973). A change in the marine climate will elicit a 

different degree of response at each level of organization, the less inclusive ecological units generally 

reacting more rapidly. Ultimately, a rearrangement 

or reorganization of these ecological units will occur. 

Although ecological systems are capable of withstanding short-term climatic changes, an enduring 

modification of the marine climate, however minor, 

should result in the appearance of new faunal associations and dis~tributions. 
44 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

SPECIES 

8 ('t) ('t) 10 0 N 0'1 00 0 10 'l:t ,.... 'l:t a; ,.... ,.... 0'1 

~ ~ ,.... 10 0 10 0'1 10 :g ,.... an N 0 ('t) 

0 0 0 0 0 0 0 ... 0 ... 0 0 

oc 

28-29 

SANTA BARBARA FORMATION 

27-28 

26-27 

25-26 

24-25 

23-24 

22-23 

21-22 

20-21 

19-20 

18-19 

18 

17-18 

16-17 

15-16 

14-15 

13-14 

13 

12-13 

11-12 

10-11 

9-10 

8-9 

I I 

7-8 I I 

I I I 

I I I 

6-7 

5-6 

FIGURE 18.-Modern temperature tolerance1s for 36 ostracode species that occur in the Santa Barbara Formation (lower Pleistocene); inferred possible yearly minimum and maximum paleotemperatures, to the nearest 1 o C, are 13o and 18o C, as 

indicated by the patterning. See table 4 for numerical list of ostracode species. 
REFERENCES CITED 45 

oc 

28-29 

27-28 

26-27 

25-26 

24-25 

23-24 

22-23 

21-22 

20-21 

19-20 

18-19 

17-18 

16-17 

15-16 

14-15 

13-14 

12-13 

11-12 

10-11 

9-10 

8-9 

7-8 

6-7 

5-6 

SPECIES 

~~~~~~~~~~~~~~~~~~~~~ 

PALOS VERDES SAND 

18 

13 

FIGURE 19.-Modern temperature tolerances for 31 ostracode 

species that occur in the Palos Verdes Sand (upper Pleistocene); inferred possible yearly minimum and maximum 

paleotemperatures, to the nearest 1 o C, are 13° and 18° C, 

as indicated by the patterning. See table 4 for numerical 

list of ostracode species. 

It would appear from thi>S study that marine clim,ates in the study area have been fluctuating during 

the past several million years within a narrow spectrum of configurations which, while influencing the 

distribution nf organisms, remain difficult to discern 

fro-m each other and from the present climate. We 

kno-w, how·ever, that at times the marine climate 

fluctuates far enough in one direction to produce 

more obvious effeots in the fossil record. For exam.ple, during the glacial advances of the Pleistocene, thermal barriers and provincial boundaries 

w·ere relocated and shifted far enough along the 

coast so that ma.rked differences between pres.ent 

and past climates are discernible. But glacial age 

deposits were laid down at low·er sea levels, and they 

are generally accessible today only through drilling 

or in uplifted sections of the coast. The patchiness 

and limited exposure of the fossil record, then, places 

a great constraint on climatic reconstructions. If a 

number of geographically dispersed fossil assemblages of equivalent age could be studied, it would 

he possible, by using the present as a model, to reconstruct an ancient climatic regime over a large 

shelf area. Studies of this nature necessarily demand 

many well-preserved fossil assemblages and are thus 

confined to the recent past. Only two such investigations have been conducted in the eastern Pacific 

(J. W. Valentine, 1961; Addicott, 1966), and these 

complementary reports employ mollusean zoogeography to reconstruct the marine climate of the late 

Pleistocene shelf off the west coast of the United 

States. As a result of the present study, the Holocene 

zoogeography of the Ostracoda can now serve as a 

datum for similar paleoclimatic reconstructions. 

REFERENCES CITED 

Addicott, W. 0., 1966, Late Pleistocene marine paleoecology and 

zoogeography in central California: U.S. Geol. Survey 

Prof. Paper 523-C, 21 p. 

Allison, E. C., 1964, Geology of areas bordering Gulf of California, in Andel, P. H., van, and Shor, G. G., Jr., eds., 

Marine geology of the Gulf of California-A symposium: 

Am. Assoc. Petroleum Geologists Mem. 3, p. 3-29. 

Bandy, 0. L., 1967, Foraminiferal definition of the boundaries 

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46 ZOOGEOGRAPHY OF HOLOCENE OSTRACODA OFF WESTERN NORTH AMERICA 

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Sci. Jour., .sec. 2, v. 11, p. 11-36. 

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Cytherideidae Sars, 1925: Tokyo U niv. Fac. Sci. Jour., sec. 

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Hartmann, Gerd, 1953, Iliocythm·e 1neyer-abichi nov. spec., ein 

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States-Ostracode zoogeography in the southern Nova 

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61-76. 

Hutchins, L. W., 1947, The bases for temperature zonation 

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17, p. 325-335. 

Ishizaki, Kunihiro, 1966, Miocene and Pliocene ostracodes from 

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ser. (Geol.), v. 37, p. 131-163. 

--- 1968, Ostracodes from Uranouchi Bay, Kochi Prefecture, Japan: Tohoku Univ. Sci. Repts., 2d ser. (Geol.), 

v. 40, p. 1-45. 

--- 1969, Ostracodes from Shinjiko and Nakanoumi, 

Shimane Prefecture, western Honshu, Japan: Tohoku 

Univ. Sci. Repts., 2d ser. (Geol.), v. 41, p. 197-224. 

--- 1971, Ostracodes from Aomori Bay, Aomori Prefecture, 

northeast Honshu Japan: Tohoku Univ. Sci. Repts., 2d 

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Ishizaki, Kunihiro, and Gunther, F. J., 1974, Ostracoda of 

the Family Cytheruridae from the Gulf of Panama: 

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Juday, Chaunc,ey, 1907, Ostracoda of the San Diego region; 

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Kern, J. P., 1973, Early Pliocene marine climate and environment of the eastern Ventura basin, southern California; 

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Kinne, 0., 1963, The effects of temperature and salinity on 

marine and brackish water animalE; Part 1, Temperature, in, Barnes, H., ed., Oceanography and marine biology-An annual review, v. 1: London, George Allen & 

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Lankford, R. R., 1962, Recent Foraminifera from the nearshore turbulent zone, western United States and northwest Mexico: Doctoral dissertation, California Univ., 

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Lankford, R. R., and Phleger, F. B, 1973, Foraminifera 

from the nearshore turbulent zone, western North America; Jour. Foraminiferal Research, v. 3, p. 101-132. 

LeRoy, L. W., 1943a, Pleistocene and Pliocene Ostracoda of the 

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v. 17, p. 354-373. 

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Lucas, V. Z., 1931, Some Ostracoda of the Vancouver Island 

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Lynn, R. J., 1967, Seasonal variation of temperature and 

salinity at 10 meters in the California Current: California cooperative oceanic fisheries investigations-Reports, v. 11, 1 July 1963-30 June 1966, California Dept. 

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McKenzie, K. G., and Swain, F. M., 1967, Recent Ostracoda 

from Scammon Lagoon, Baja California: Jour. Paleontology, v. 41, p. 281-305. 
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Margalef, Ramon, 1968, Perspectives in ecological theory: 

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Pokorny, Vladimir, 1968, Radimella gen. n., a new genus of 

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--- 1967, New generic assignments for some Pleistocene 

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488. 

Schmidt, R. A. M., and Sellmann, P. V., 1966 Mummified 

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n U.S. GOVERNMENT PRINTING OFFICE: 1976 0-211-317/63 

PLATES 1-14 

Contact photographs of the plates in this report are available, at 

CO!St, from U.S. Geological Survey Library, Federal Center, 

Denver, Colorado 80225 
PLATE 1 

[All figures are lateral views; all X 60] 

FIGURES 1, 2, 4, 5. Ambostracon costatum Hazel, 1962. 

1. Right valve, male. Santa Barbara Formation. USNM 207779. 

2. Right valve, female. Santa Barbara Formation. USNM 207780. 

4. Left valve, male. Santa Barbara Formation. USNM 207781. 

5. Left valve, female. Santa Barbara Formation. USNM 207782. 

3, 6. Ambostracon sp. M. 

3. Right valve, female. Sample 164. USNM 207783. 

6. Right valve, male. Sample 164. USNM 207784. 

7, 8. Ambostracon sp. A. 

7. Left valve, male. Sample 1. USNM 207785. 

8. Left valve, female. Sample 10. USNM 207786. 

9, 12. Ambostracon sp. B. 

9. Left valve, male. Sample 101. USNM 207787. 

12. Left valve, female. Sample 101. USNM 207788. 

10, 11, 13, 14. Ambostracon sp. G. 

10. Left valve, male. Sample 177. USNM 207789. 

11. Left valve, female. Sample 177. USNM 207790. 

13. Left valve, male. Sample 117. USNM 207791. 

14. Left valve, female. Sample 117. USNM 207792. 

15,18. Ambostracon glaucum (Skogsberg, 1928). 

15. Left valve, female. Sample 193. USNM 207793. 

18. Left valve, male. Sample 193. USNM 207794. 

16, 17. Ambostracon sp. E. 

16. Left valve, male. Sample 59. USNM 207795. 

17. Left valve, female. Sample 59. USNM 207796. 
GEOLOGICAL SURVEY 

1 

4 

7 

16 

5 

11 

17 

AMBOSTRACON 

PROFESSIONAL PAPER 916 PLATE 1 

3 

6 

9 

12 

15 

18 
PLATE 2 

[All figures are lateral views; all X 60] 

FIGURES 1, 4. Ambostracon sp. J. 

1. Left valve, female. Sample 193. USNM 207797. 

4. Left valve, male. Sample 193, USNM 207798. 

2, 3. Ambostracon sp. 0. 

2. Left valve, male. Sample 222. USNM 207799. 

3. Left valve, female. Sample 222. USNM 207800. 

5, 6, 8, 9. Ambostracon sp. L. 

5. Left valve, male. Sample 164. USNM 207801. 

6. Left valve, female. Sample 164. USNM 207802. 

8. Left valve, male. Sample Mf2176. USNM 207803. 

9. Left valve, female. Sample Mf2176. USNM 207804. 

7, 10. Ambostracon diegoensis (LeRoy, 1943). 

7. Left valve, female. Sample 201. USNM 207805. 

10. Left valve, male. Sample 201. USNM 207806. 

11, 14. Ambostracon sp. K. 

11. Left valve, female. Sample 244. USNM 207807. 

14. Left valve, male. Samnle 244. USNM 207808. 

12, 13. A mbostracon cali.fornicum (Hazel. 1962) . 

12. Left valve, male. Sample Mf2169. USNM 207809. 

13. Left valve, female. Sample Mf2169. USNM 207810. 

15, 16. Ambostracon sp. D. 

15. Left valve, male. Sample Mf2l74. USNM 207811. 

16. Left valve, female. Sample Mf2174. USNM 207812. 
GEOLOGICAL SURVEY 

1 

4 

7 

10 

11 

14 

2 

8 

15 

AMBOSTRACON 

PROFESSIONAL PAPER 916 PLATE 2 

3 

6 

9 
FIGURES 

PLATE 3 

[All figures are lateral views; all X 60] 

1. Ambostracon microreticulatum (LeRoy, 1943). 

Left valve, female. Sample 201. USNM 207813. 

2. Ambostracon sp. Q. 

Left valve, female. Sample 242. USNM 207814. 

3. Ambostracon sp. F. 

Left valve, female. Sample 202. USNM 207815. 

4, 7, 10. Coquimba sp. A. 

4. Left valve, male. Sample Mf2174. USNM 207816. 

7. Left valve, female. Sample Mf2174 USNM 207817. 

10. Right vaJve, female. Sample Mf2174. USNM 207818. 

5, 8, 11. Coquimba schencki (LeRoy, 1943). 

5. Left valve, male. Sample Mf2174. USNM 207819. 

8. Left valve, female. Sample Mf2174. USNM 207820. 

11. Right valve, female. Sample Mf2174. USNM 207821. 

6, 9. New genus F sp. A. 

6. Right valve. Sample 1. USNM 207822. 

9. Left valve. Sample 15. USNM 207823. 

12. Buntonia sp. B. 

Left valve, female. Sample 154. USNM 207824. 

13, 14. Puriana pacifica Benson, 1959. 

13. Left valve, female. Sample 197. USNM 207825. 

14. Right valve, female. Sample 197. USNM 207826. 

15, 18. Buntonia sp. A. 

15. Left valve, female. Sample Mf2180. USNM 207827. 

18. Right valve, female. Sample Mf2180. USNM 207828. 

16, 17. Puriana sp. A. 

16. Left valve, female. Sample 254. USNM 207829. 

17. Right valve, female. Sample 254· USNM 207830. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 3 

1 2 

3 

6 

9 

11 

16 17 18 

AMBOSTRACON, BUNTON/A, COQUIMBA, NEW GENUS F, AND PURIANA 
PLATE 4 

[All figures are lateral views; all X 60] 

FIGURES 1. Her'YIU1nites sp. E. 

Left valve, male. Sample 215. USNM 207831. 

2, 5. Her'YIU1nites kewi (LeRoy, 1943). 

2. Left valve, female. Sample Mf217 4. USNM 207832. 

5. Left valve, female. Sample Mf2180. USNM 207833. 

3. Sahnia sp. A. 

Left valve. Sample 197. USNM 207834. 

4. H er'YIU1nites sp. G. 

Left valve, female. Sample 203. USNM 207835. 

6, 7. Pulmilocytheridea pseudoguardensis McKenzie and Swain, 1967. 

6. Left valve, female. Sample 233. USNM 207836. 

7. Right valve, female. Sample 233. USNM 207837. 

8. Hermanites sp. D. 

Left valve, female. Sample 215. USNM 207838. 

9. Hermanites sp. C. 

Left valve, female. Sample 193. USNM 207839. 

10, 14. "Cytheretta" sp. B. 

10. Right valve, male. Sample 141. USNM 207840. 

14. Right valve, female. Sample 141. USNM 207841. 

11. Hermanites sp. A. 

Left valve, male. Sample 215. USNM 207842. 

12, 15. Cytheropteron sp. A. 

12. Left valve, female. Sample 35. USNM 207843. 

15. Right valve, female . Sample 35. USNM 207844. 

13, 16, 17. "Cytheretta" sp. A. 

13. Right valve, male. Sample 61. USNM 207845. 

16. Right valve, female. Sample 61. USNM 207846. 

17. Left valve, female. Sample 61· USNM 207847. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 4 

"CYTHERETTA," CYTHEROPTERON, HERMANITES, PULMILOCYTHERIDEA, AND SAHNIA 
FIGURES 

PLATE 5 

[All figures are lateral views; all X 60 except where noted] 

1, 2. Pontocythere sp. C. 

1. Right valve, female. Sample 15. USNM 207848. 

2. Left valve, female. Sample 15. USNM 207849. 

3, 8. Paracytheridea granti LeRoy, 1943. 

3. Right valve, female. Sample 122. USNM 207850. 

8. Left valve, female. Sample 122. USNM 207851. 

4, 5. Pontocythere sp. A. 

4. Right valve, female. Sample 197. USNM 207852. 

5. Left valve, female. Sample 197. USNM 207853. 

6, 7. Pontocythere sp. B. 

6. Right valve, f emale. Sample 197. USNM 207854. 

7. Left valve, female. Sample 197. USNM 207855. 

9, 10. Paracytheridea sp. B. 

9. Right valve, f emale. Sample 221. USNM 207856. 

10. Left valve, female. Sample 221. USNM 207857. 

11, 14. Paracytheridea sp. A. 

11. Left valve, female. Sample 164. USNM 207858. 

14. Right valve, female. Sample 164. USNM 207859. 

12, 13. "Kangarina" sp. A. 

12. Left valve. Sample 109. X 120. USNM 207860. 

13. Right valve. Sample 2. X 120. USNM 207861. 

15. Kangarina sp. B. 

Right valve, f emale. Sample 215. X 120. USNM 207862. 

16. Kangarina sp. C. 

Right valve, f emale. Sample 99. X 120. USNM 207863. 

17. Kangarina aff. K. quellita Coryell and Fields, 1937. 

Right valve, female. Sample 242. X 120. USNM 207864. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 5 

1 2 

3 

4 5 

8 

6 7 

9 10 11 

14 

12 13 

15 16 17 

KANGARINA, "KANGARINA;' PARACYTHERIDEA, AND PONTOCYTHERE 
FIGURES 

PLATE 6 

[All figures are lateral views; all X 120 except where noted] 

1, 2. Loxocorniculum sp. A. 

1. Left valve, male. Sample 221. X 60. USNM 207865. 

2. Left valve, female. Sample 221. X 60. USNM 207866. 

3. Loxocorniculum sp. B. 

Left valve, female. Sample 251. X 60. USNM 207867. 

4. "Loxoconcha" emaciata Swain, 1967. 

Left valve, female. Sample 251. X 60. USNM 207868. 

5. Hemicytherura sp. D. 

Right valve, female. Sample 57. USNM 207869. 

6. Hemicytherura sp. F. 

Right valve, female. Sample 215. USNM 207870. 

7. Hemicytherura sp. G. 

Right valve, female. Sample 244. USNM 207871. 

8. H emicytherura sp. L. 

Right valve, female. Sample 108. USNM 207872. 

9. Hemicytherura sp. H. 

Right valve, female. Sample 108. USNM 207873. 

10. Hemicytherura sp. K. 

Right valve, female. Sample 215. USNM 207874. 

11. Hemicythererura sp. J. 

Right valve, female. Sample 202. USNM 207875. 

12. Hemicytherura sp. C. 

Right valve, female. Sample 222. USNM 207876. 

13. Hemicytherura sp. I. 

Right valve, female. Sample 215. USNM 207877. 

14. Hemicytherura sp. B. 

Right valve, female. Sample 109. USNM 207878. 

15, 16. Hemicytherura sp. A. 

15. Right valve, female. Sample 2. USNM 207879. 

16. Left valve, female. Sample 2. USNM 207880. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 6 

1 

HEMICYTHERURA, "LOXOCONCHA," AND LOXOCORNICULUM 
FIGURES 

PLATE 7 

[All figures are lateral views; all X 60] 

1, 2. Loxoconcha lenticulata LeRoy, 1943. 

1. Left valve, f emale. Sample Mf2174. USNM 207881. 

2. Left valve, male. Sample Mf217 4. USNM 207882. 

3, 7. "Aurila" sp. C. 

3. Right valve, female. Sample 193. USNM 207883. 

7. Left valve, female. Sample 193. USNM 207884. 

4, 5. Loxoconcha sp. A. 

4. Right valve, female. Sample 15. USNM 207885. 

5. Left valve, female. Sample 15. USNM 207886. 

6. Loxoconcha helenae Crouch, 1949. 

Left valve, femal e. Sample 82. USNM 207887. 

8, 12. Loxoconcha sp. B. 

8. Left valve, female. Sample 193. USNM 207888. 

12. Left valve, male. Sample 193. USNM 207889. 

9. Loxoconcha sp. E. 

Left valve, female. Sample 184. USNM 207890. 

10, 11. Aurila sp. B. 

10. Right valve, female. Sample 211. USNM 207891. 

11. Left valve, female . Sample 211. USNM 207892. 

13, 16. "Aurila" sp. E. 

13. Left valve, male. Sample 40. USNM 207893. 

16. Left valve, female. Sample 40. USNM 207894. 

14, 17. "Aurila" driveri (LeRoy, 1943). 

14. Right valve, female, Sample Mf2176. USNM 207895. 

17. Left valve, female. Sample Mf2176. USNM 207896. 

15. "Aurila" schumannensis (LeRoy, 1943). 

Left valve, female. Sample 96. USNM 207897. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 7 

1 

4 7 

8 9 10 11 

12 

15 16 17 

A URILA, "A URI LA;· AND LOXOCONCHA 
FIGURES 1-4. 

5-8. 

9, 10, 12, 13, 

15, 16, 18, 19. 

11, 14. 

17, 20. 

PLATE 8 

/All figures are lateral views; all X 60] 

A urila sp. C. 

1. Left valve, male. Sample 109. USNM 207898. 

2. Right valve, male. Sample 109. USNM 207899. 

3. Right valve, female. Sample 109. USNM 207900. 

4. Left valve, female. Sample 109. USNM 207901. 

A urila lincolnensis (LeRoy, 1943) . 

5. Left valve, male. Sample 67. USNM 207902. 

6. Right valve, male. Sample 67. USNM 207903. 

7. Right valve, female. Sample 67. USNM 207904. 

8. Left valve, female. Sample 67. USNM 207905. 

Aurila sp. A. 

9. Left valve, male. Sample 67. USNM 207906. 

10. Right valve, male. Sample 67. USNM 207907. 

12. Left valve, female. Sample 67. USNM 207908. 

13. Right valve, female. Sample 67. USNM 207909. 

15. Left valve, male. Sample 3. USNM 207910. 

16. Right valve, male. Sample 3. USNM 207911. 

18. Left valve, female. Sample 3. USNM 207912. 

19. Right valve, female. Sample 3. USNM 207913. 

Aurila sp. D. 

11. Left valve, female. Sample 109. USNM 207914. 

14. Right valve, female. Sample 109. USNM 207915. 

Aurila montereyensis (Skogsberg, 1928). 

17. Right valve, female. Sample 108. USNM 207916. 

20. Left valve, female. Sample 108. USNM 207917. 
GEOLOGICAL SURVEY 

9 

15 

18 

10 

13 

16 

19 

AURILA 

PROFESSIONAL PAPER 916 PLATE 8 

7 8 

14 

17 

20 
FIGURES 

PLATE 9 

[All figures are lateral views; all X 60] 

1, 4. Cytheromorpha sp. A. 

1. Left valve, male. Sample 2. USNM 207918. 

4. Left valve, female. Sample 2. USNM 207919. 

2, 3. Cytheromorpha sp. B. 

2. Left valve, male. Sample 2. USNM 207920. 

3. Left valve, female. Sample 2. USNM 207921. 

5, 6. "Radimella" aurita ( Skogsberg, 1928). 

5. Left valve, female. Sample 177. USNM 207922. 

6. Left valve, male. Sample 177. USNM 207923. 

7, 10. Radimella palosensis (LeRoy, 1943). 

7. Left valve, female. Sample 101. USNM 207924. 

10. Left valve, male. Sample 101. USNM 207925. 

8, 11. Radimella sp. B. 

8. Left valve, female. Sample 244. USNM 207926. 

11. Left valve, male. Sample 244. USNM 207927. 

9, 12. Radimella sp. A. 

9. Left valve, female. Sample 202. USNM 207928. 

12. Left valve, male. Sample 202. USNM 207929. 

13, 16. "Radimella" jollaensis (LeRoy, 1943). 

13. Left valve, female. Sample 177. USNM 207930. 

16. Left valve, male. Sample 177. USNM 207931. 

14, 17. "Radimella" sp. A. 

14. Left valve, female. Sample 67. USNM 207932. 

17. Left valve, male. Sample 67. USNM 207933. 

15. "Radimella" pacifica ( Skogsberg, 1928). 

Left valve, female. Sample 108. USNM 207934. 

18. "Radimella" sp. B. 

Left valve, female. Sample 201. USNM 207935. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 91 6 PLATE 9 

1 

CYTHEROMORPHA , RADJMELLA, AND "RADIMELLA " 
FIGURES 

PLATE 10 

[All figures are lateral views; all X 60 except where noted] 

1, 2. Munseyella sp. A. 

1. Right valve, female. Sample 197. USNM 207936. 

2. Left valve, female. Sample 197. USNM 207937. 

3, 4. Palmenella californica Triebel, 1957. 

3. Left valve, female. Sample 141. USNM 207938. 

4. Right valve, female. Sample 141. USNM 207939. 

5, 6. Munseyella sp. B. 

5. Left valve, female. Sample 96. USNM 207940. 

6. Right valve, female. Sample 96. USNM 207941. 

7, 12. Munseyella similis? Triebel, 1957. 

7. Left valve, male. Sample Mf2180. X 120. USNM 207942. 

12. Left valve, female. Sample Mf2180. X 120. USNM 207943. 

8-11. Pectocythere sp. A. 

8. Left valve, female. Sample Mf2180. USNM 207944. 

9. Right valve, female. Sample Mf2180. USNM 207945. 

10. Left valve, male. Samp.le 2. USNM 207946. 

11. Right valve, male. Sample 2. USNM 207947. 

13, 14. Pectocythere clavata (Triebel, 1957). 

13. Left valve, female. Sample 117. USNM 207948. 

14. Right valve, female. Sample 117. USNM 207949. 

15, 18. Munseyella pedroensis Triebel, 1957. 

15. Left valve, female. Sample Mf2174. X 120. USNM 207950. 

18. Right valve, female. Sample Mf2174. X 120. USNM 207951. 

16, 17. Pectocythere tomalensis Watling, 1970. 

16. Left valve, female. Sample 68. USNM 207952. 

17. Right valve, femal e. Sample 68. USNM 207953. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 10 

1 

3 4 

6 

7 

9 

11 

16 17 

MUNSEYELLA, PALMENELLA, AND PECTOCYTHERE' 
FIGURES 1, 4. 

2, 5. 

3, 6. 

7, 11. 

8, 12. 

9, 13. 

10, 14. 

15, 16, 18, 19. 

17, 20. 

PLATE 11 

[All figures are lateral views; all X 60) 

Palaciosa sp. A. 

1. Left valve, female. Sample 108. USNM 207954. 

4. Right valve, female. Sample 108. USNM 207955. 

Palaciosa sp. B. 

2. Left valve, female. Sample 101. USNM 207956. 

5. Left valve, male. Sample 101. USNM 207957. 

Orionina pseudovaughni Swain, 1967. 

3. Left valve, female. Sample 233. USNM 207958. 

6. Right valve, female. Sample 233. USNM 207959. 

Caudites sp. B. 

7. Left valve, female. Sample 221. USNM 207960. 

11. Right valve, female. Sample 221. USNM 207961. 

Caudites fragilis LeRoy, 1943. 

8. Left valve, female. Sample 197. USNM 207962. 

12. Right valve, female. Sample 197. USNM 207963. 

Caudites sp. D. 

9. Left valve, female. Sample 242. USNM 207964. 

13. Right valve, female. Sample 242. USNM 207965. 

Caudites sp. E. 

10. Left valve, female. Sample 241. USNM 207966. 

14 .. Right valve, female. Sample 241. USNM 207967. 

Caudites purii (McKenzie and Swain, 1967). 

15. Left valve, female. Sample 242. USNM 207968. 

16. Right valve, female. Sample 242. USNM 206969. 

18. Left valve, male. Sample 233. USNM 207970. 

19. Right valve, male. Sample 233. USNM 207971. 

TTiebelina reticulopunctata Benson, 1959. 

17. Right valve, female. Sample 221. USNM 207972. 

20. Left valve, female. Sample 221. USNM 207973. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 11 

1 2 3 

5 6 

7 8 9 10 

11 12 13 14 

15 16 

17 

18 19 20 

CAUDITES, ORJONINA, PALACJOSA , AND TRIEBELINA 
PLATE 12 

[All figures are later al views; all X 60] 

FIGURES 1, 4, 7, 10. Hemicythere sp. A. 

1. Right valve, female. Sample 32. USNM 207974. 

4. Left valve, female. Sample 32. USNM 207975. 

7. Right valve, male. Sample 32. USNM 207976. 

10. Left valve, male. Sample 32. USNM 207977. 

2, 5, 8, 12. HemicytheTe sp. B. 

2. Right valve, female. Sample 40. USNM 207978. 

5. Left valve, female. Sample 40. USNM 207979. 

8. Right valve, male. Sample 40. USNM 207980. 

12. Left valve, male. Sample 40. USNM 207981. 

3, 6. Cythere maia (Benson, 1959). 

3. Right valve, female. Sample 109. USNM 207982. 

6. Left valve, female. Sample 109. USNM 207983. 

9, 13. Cythere sp. B. 

9. Right valve, female. Sample 40. USNM 207984. 

13. Left valve, female. Sample 40. USNM 207985. 

11. Basslerites thlipsuroidea Swain, 1967. 

Left valve. Sample 255. USNM 207986. 

14. Basslerites delreyensis LeRoy, 1943. 

Left valve, female. Sample 215. USNM 207987. 

15, 16. Cythere sp. A. 

15. Right valve, female . Sample 31. USNM 207988. 

16. Left valve, female. Sample 31. USNM 207989. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 12 

1 

4 

5 

7 

8 

10 

0 . 

. . 

. 

I 

11 

14 15 

BASSLERITES, CYTHERE, AND HEMICYTHERE 
FIGURES 

PLATE 13 

[All figures are lateral views; all X 60] 

1, 6. Cativella semitranslucens (Crouch, 1949). 

1. Left valve, female. Santa Barbara Formation. USNM 207990. 

6. Right valve, f emale. Santa Barbara Formation. USNM 207991. 

2. Cativella sp. A. 

Left valve, female. Sample 222. USNM 207992. 

3. Cativella sp. B. 

Left valve, female. Sample 255. USNM 207993. 

4, 5, 7. "Paijenborchella" sp. B. 

4. Right valve, female. Sample 101. USNM 207994. 

5. Left valve, female. Sample 101. USNM 207995. 

7. Right valve, female. Sample Mf2180. USNM 207996. 

8, 11. "Paijenborchella" sp. A. 

8. Right valve, female. Sample 8. USNM 207997. 

11. Left valve, female. Sample 8. USNM 207998. 

9, 12. "TTachylebeTis" sp. A. 

9. Left valve, male. Sample 255. USNM 207999. 

12. Left valve, female. Sample 255. USNM 208000. 

10. Neocaudites? henryhowei (McKenzie and Swain, 1967). 

Left valve, female. Sample 215. USNM 208001. 

13, 14. Costa? sanfelipensis Swain, 1967. 

13. Left valve, male. Sample 255. USNM 208002. 

14. Left valve, female. Sample 255. USNM 208003. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 13 

3 

1 

4 

6 

7 

10 

12 

CAT/VELLA, COSTA?, NEOCAUDITES?, "PAIJENBORCHELLA," AND "TRACHYLEBERIS" 
PLATE 14 

[All figures are lateral views; all X 60] 

FIGURES 1, 2, 4, 5. "Hemicythere" sp. A. 

1. Left valve, female. Sample Mf2176. USNM 208004. 

2· Left valve, male. Sample Mf2176. USNM 208005. 

4. Left valve, female. Sample 164. USNM 208006. 

5. Left valve, male. Sample 164. USNM 208007. 

3, 6. "Hemicythere" sp. B. 

3. Left valve, female. Sample 203· USNM 208008. 

6. Left valve, male. Sample 203. USNM 208009. 

7, 8. "Hemicythere" californiensis LeRoy, 1943. 

7. Left valve, female . Sample Mf2176. USNM 208010. 

8. Left valve, male .. Sample Mf2176. USNM 208011. 

9. "Hemicythere" sp. C. 

Left valve, male. Sample 222. USNM 20812. 

10, 11. "Hemicythere" hispida LeRoy, 1943. 

10. Left valve, femaJe. Sample Mf2174. USNM 208013. 

11. Left valve, male .. Sample Mf2176. USNM 208014. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 916 PLATE 14 

4 

"HEMICYTHERE"