Professional Paper No. 47 Series 0, Systematic Geology and Paleontology, 76 

DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

CHARLES D. WALCOTT, DIRECTOR 

THE 

TERTIARY AND QUATERNARY PECTENS 

OF CALIFORNIA 

BY 

RALPH ARNOJ~D 

'V ASHINGTON 

GOVERNMENT PRINTING OFFICE 

1906 
. .. . . . . . . . .. .. . :. ···.: ··· ... ::: ·=·:: . .. : . ••• •• . • . : : • & •• : • •• : • • : • • • • • • • 

.. : .. . . .. . . . . . . . . ... . . . . . . . . . .. : ... : . · .. : : . . . . . . . . . . . . . . ·: .· : :. ·. : : ...... . . .. . . . ..;.·-··:' 

· ... ·:r· ... :·::. ==·~ \ ·: .. : ·: . . '. . 
CONTENTS AND ILLUSTHA 'fiONS. 

Page. 

INTRODUCTION------- ---- -- - - - - - - - - - - - - - --- - ---- - - - - - - - - - - - - -- -- - ------ - - - ----- - --- - ------- 7 

PART I. THE TERTIARY AND PLEISTOCENE FoRMATIONs oF CALIFORNIA ______________________ _ 9 

Post-Cretaceous geologic column ________________________ c __________________ .--- _------- 9 

Post-Cretaceous correlation table _____________________________________________________ _ 9 

Eocene ______________________________________________________________________________ _ 10 

Martinez formation _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ______________________________________________ _ 11 

Type locality ________________________________________________________________ _ 

Name and description _____________________________________ ~ _________________ _ 11 

11 \ 

Definition ___________________________________________________________________ _ 11 

Localities _____ . ___________ ............. _ . . _ . _________ . __ . __________ . _________ _ 11 

Fauna ____ . __ .. ______ ._ .. _____ . ______ . ______ · _____ . _____________________ .. ____ _ 11 

Pecten fauna ______ . __ .. _ . ___ . ___ .. _____________ . __ . _____________________ _ 11 

List of Martinez formation ( lo·wer Eocene) fossils ________ . _ . _ ... ____ ... ___ _ 12 

Tejon formation __ . __ .. ___ . . ____ . _____ . ___ . _ . _______ .. _____________________ . _ . ___ . 13 

Type locality_ .. _______ . ___ . ________ .. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _______ . ________ . ___ .. 13 

Name and description ___ .. ___ . __________________ . __________ . _______ . ___ .. ___ _ 13 

Definition __ :-. __________________ . ____________________________ . ____ '. __________ . 13 

Localities. ___________ .. ____ _ ________________________________ . ________ . _. ____ . 13 

Fauna _____ . ____ . __________ . ______________________ . __ . ____ .. ____________ . ____ _ 14 

Pecten fauna _ . _____________________ . ______ . __________________________ . __ _ 14 

List of Tejon formation (Eocene) fossils .... ----------------··-------------- 14 

0 ligocene _ . _______ . _ ... __________ .. __________ . _____ .. _______________________ . _ -. _ .... __ 15 

San Lorenzo formation ____ . ____ . _ . ______________ . _____________________________ . __ _ 16 

Type locality ____________________ . ___ . . _. _______ . __________________ .. ________ _ 16 

Definition ____ . ______________________ . ___________ .. ________ . _________________ _ 16 

Localities .. _____ . ____ . ______ . ____ .. ____ .. _____ . ______________ -_· _________ . ___ _ 16 

Fauna _________________ . ________ . _____ .. ________ . __ . _________________________ _ 16 

Pecten fauna _____________ . _____________ . ___ . _________ . ___ .... ~ .. ________ _ 16 

List of San Lorenzo formation (Oligocene) fossils. ____ . ___ .. ______ . _____ .. _ 17 

Miocene ___ . _ . ____ .. __ . _ . _______________ . ____ . ______ . ____ . __ ..... - - - -.. - - - -. - - - -.. ---- 17 

Vaqueros sandstone ________ . _. _ ... ______ .. _ ... ______ . __ ... ________ ....... _. _ ... ___ _ 18 

Type locality ..... ____ ...... _____ ._. ______________ .... __ .... _. ____ .. __ .. _._. __ 18 

N arne and description . . _ .. _________ .... _ ... ____ ... _ . _________ ... _ . _ .. _ .. ___ . __ 18 

Definition . __ .. _ .. ______ . ________ . _ . ________________ . ___________________ .. ___ _ 18 

Localities. ____________________ . ____ . __________________ . ______ . ________ ._. ____ _ 18 

Fauna __ ... ______________________ .... __ . _ . _ .. _ .. ______ . ____ . ____ . _____________ _ 18 

Pecten fauna _____________ . ___________________ . _ .. ___ ... ____ .. ___ . _. _ .... _ 18 

List of Vaqueros sandstone (lower Miocene) fossils~. ___ .... _____ . ___ .. ____ _ 19 

Monterey shale ___ . _ . _ .. ____ ... _________ . __ . ________ . __________________ . ___ . ____ .. 20 

Type locality __________ ...... _____ . ___ . ____ .. __ . ______________ . __________ . ____ _ 20 

Name and description _. _ .. _____ .. _________ .. ____________________ .... _. _ .. _ .. ~ _ 20 

Definition _______ ..... ___ . ____ ... ___ .... ________ ...... _. __ . _ .......... _ .. ____ . 20 

Localities. _ .. ______ .. __ ...... _____________________ .. ___ . _ ... _______ . _________ . 20 

3 
I 

4 CONTENTS AND ILLUSTRATIONS. 

PART I. THE TERTIARY AND PLEISTOCENE FoRMATIONs OF CALIFORNIA-Continued. 

Miocene-Contin~ed. 

Monterey shale-Continued. . Page. 

Fauna ___________ ..... _ .. _ .. _____ ..... ___ .. _ ..... _. ____________________ . _ . _ _ _ _ _ 21 

Pecten fauna . ___________ . ____________________________ . __ .... _ ......... _ . . . 21 

List of Monterey shale (middle Miocene) fossils ______ ·- .................. _ 21 

List of fossils from the Carrizo Creek beds (Miocene) ... __ . __ . __ . _ _ _ _ _ _ _ _ _ 22 

San Pablo formation. ___________ ... ___ ... _____ .... ______ . __ ..... ________________ . _ 22 

Type locality ... ____________ . __ . __ . ___ . ____ .. . -_______ ...... _· _______ . ___ . __ . _ . _ 22 

Name and description _____ . _ . _ ... _ . _ .. __ ... ______ . ________ . ___ ..... ____ . _ _ _ _ _ 22 

Definition ___________ . _: _ _ _ _ _ _ _ _ ___ .... __ .. __ : __ . ________________ . _____ . _ _ _ _ _ 22 

Localities _ . __ ... ___ ... _ ... _____ . _______ .. _ .. _ . _ .. _ ... ____ . _________________ . _ _ 22 

· Fauna . .. _._ ....... ___ .. _ .. ___ .. ______________ . _____ . ___ ... _________ ... __ . _ _ _ 23 

Pecten fauna ___ .. ·._._ .... _ ... __ . ___ .. ___ .. _ .. __ ._. _____ ... _______ -. -.. ___ . 

List of San Pablo formation (upper Miocene) fossils ....... __ ...... _. _____ . 

List of Santa Margarita formation ( = San Pablo) fossHs from Salinas 

Valley and southward ....... ~ _. ___ .. _______ .; .. _.; __ ... ________ . __ ...... . 

Pliocene ..... ______ ... _ ... __ . ____ ... __ ..... _ . __ . _ . . . ... _ .; _ . .; ... _ .. __ .. _ .•............. 

Purisima formation_ ... __ ._ ... __ . _____ .~. __ ._ ..... ___ .;._.;._ ..... _ .. ~ ___ . _ ......... . 

Type locality_.·_. _. ~ ___ . _ .. ___ . __ ..... __ ... _ ... .; .· ................. · ........... . 

N arne and description _. _ .... __ ... _ . _ .. _ ...... __ ... __ .... _ .-....... _. __ ........ . 

Definition ... _ .......... _ .. _ .... _. _. ___ ....... _______ .. _ ~ _:.: ____ . ____ .... . _. __ 

Localities._. __ ... _____ ...... ____ .................. ....... ----------.----------

23 

23 

24 

25 

25 

25 

25 

25 

26 

Fauna .... __ .. ________ .... _ ... ____ .. _ .. _ . . .. _______ . _ . __ . _____ . __________ . _ _ _ _ 26 

Pecten fauna . _____ .... _ . ___ .. _ . _ . __ . _____ .. _ .. ___ .... ______ .. ______ ___ . . . 26 

List of Purisima formation (lower Pliocene) fossils . _____ . __ . _. ______ .. ___ . 27 

List of San Diego formation fossils. _______ . ___ . _________ ... __ ... ___ .. _____ 28 

Merced formation . ___________ _ .. . _ . __ ____ .... __ . __ . __ . ____ .. ______ . ______ . ____ . _ _ _ 28 

Type locality ..... _________ .. __ . __________ .. _. __ . ___ .. __ . __ _ : ________ . _ . . _. __ . _ 28 

Name and description ...... _. _______ .. ___________ .. ______ ... _ ... _____ . _. ____ . 28 

_ Definition _____ . _____ .... ___ .. __ . __ ... ____ .. ___ . __ . ____ . ____ ___ .. ________ . __ .. 29 

Localities .. _._. _. ___ .... ___ ... __ .... ____ .,. __ ~. __ ~ ____ . _____ ...... _____ ... ___ . 29 

Fauna. ________ . __ . ____ .. __ . _______ ... ______________ . _________ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 29 

Pecten fauna _____ . __ . ___ . __ ... _ . ___ . _ . _ .. ___ . _________ ... ______ ........ _ . 29 

List of Merced formation (upper Pliocene) fossils .... _______ ..... ____ .... __ 30 

List of Pliocene fossils from Dead.man Island .. ____ . ___ ...... _ ... ____ . . .... 30 

Pleistocene ................... _______ . __ . .. _ ..... _ . ______ .... ______ . _ . _ .. ________ .. ___ . 31 

San Pedro formation _ . _________ ___ ____ . _____ . ____________________________ .. _ _ _ _ _ _ 32 

Type locality .. _________ . __ ..... _ ..... _._ .. __ . _._ ... _ .. _____ . ___ .. _____________ 32 

Name and description _____ . ___________ . ___ . __ .. ___ .. ____ . _ ... ___________ . _ .. _ 32 

Definition . __ ••• ________ . _ .... _. ___ . ___ . _______ . _. _. __ . _ .. _ ..... _____ __ ______ . 32 

Localities ••••••••••• __ ._. __ . _______ .. ______ . __ • __ . __ . ___ ......... _____ . ___ . _ _ _ ~2 

Fauna .. ___ ...••••••• ___ ...... __ ............ _ ..... _ ... ____ .... __________ . __ .. _ 33 

Pecten fauna ••... __ . . .... ___ . _ ........ ___ ........... _______________ . • _ _ _ _ 33 

List of San Pedro formation (Pleistocene) fossils ... _._. ____ . ____ . __ . ____ . _. 33 

Geologic range of the California Pectens _______ . ___ . __ . ___ ........ ____ . ________ . _ .. _ . _ 37 

Summary of the range of species and varieties ............ 1_____________________ _ ___ 40 

PART II. SYNOPSIS AND DEscRIPTIONs oF SuBGENERA AND SPEcms . _________ .. ____ . ___ . ____ .. 41 

Synopsis of subgenera and species ....... _._. __ ._ .... __ . ______ . ________ .. ___________ ... 41 

Summary of the subgenera and species. __ . ____ .. .. .... _ .. ____ ......... ____ ......... 44 

Descriptions of subgenera and species . __ .. __ .... __ .. ______ . . _________________ .. _ .. __ . _ 45 

Genus Pecten Muller ___ .. _________ .. ___ . ____ .. ___ . ____________ ... _______ . ____ .... 45 

Subgenus Pecten s. s. M iiller .... __ . __ ... __ ... __ . . ...... _. _ ......•......... _ . . . 48 

Subgenus Patinopecten Dall . . _ ..... __ . __________ ..... ______ . __ ..... __ . ___ . _. _. 48 

Subgenus Nodipecten Dall____________________________________________________ 49 
. I 

CONTENTS AND ILLUSTRATIONS. 5 

Part II. SYNOPSIS AND DEsCRIP'riONS OF SuBGENERA A~D SPECIEs-Continued. 

Descriptions of subgenera and species-Continued. 

Genus Pecten Muller-Continued. Page. 

Subgenus Chlamys Bolte1; ____ ......................... _ ..•...... _ ..•...... ~ _ ~ 49 

Subgenus Lyropecten Conrad ... _ . _ . _ . _ ... _ . _ . _ . __ .. _ ... _ . __ . ___ . . . . . . . . . . . . • • 49 

Subgenus JEquipecten Fischer ... _____ . ___ ._ ..... _. __ .. _ ..... _. __ .......... _._. 49 

Subgenus Plagioctenium Dall . __ . _. _____ .. _. _ ... __ . _. _____ .. • ...... _ ... _ .. _. _. _ 50 

Subgenus Pseudamusium H. and A. Adams .... -----------------~-------------- 50 

Subgenus Amusium Bolten ......... . . _ .... ____ .................... _ ...... __ ... 50 

Subgenus Propeamusium Gregorio ____ ..... __ .......... ____ .... __ ........ _ ... _. 50 

Subgenus Hinnites Defrance .. _ .. _. _ . ....... _. __ _ . . . _ .... _. __ .... _ . _ ...... _... 50 

Eocene Pectens .. ~ _ ............... ~ ..... _ .......... _ .... ~ . . . . . . . . . . . . . . . . . . . . . . . . . 51 

Oligocene Pectens . _ ..... _ •.......... _ .. _ ... _. __ ... _. _. _ .. ____ ........... _ ... _. __ . 54 

Miocene Pectens ...... __ ... _ ......... _ . ___ .... __ . _ .... _ .. _ ........ _ .. _ ....... ___ . . . 59 

Pliocene Pectens. _ . __ ............... . ..... _ .. __ ........ _ . _ . _ . __ ...... ___ ... _ . _ .. _ . 94 

Pleistocene Pectens .............. ____ . ______ . ___ _____________ . _________ ... _______ . 127 

Recent Pectens _______ . _. _ ..... _ . . _ ... _ .. ____ . ___ .. __ . _ .. ___________ . _______ .. __ .. 134 

Unidentifiable Pectens. __ ... __ .. __ . ___ . _______ .. __ ... ___ ... ~ __ .. __________________ 141 

Bi bliogra ph y .. _ ... __ .. __ ... _ ..... __ .. _ . _ .. __ . ____ . ___ . .. _ .... . ....... __ .. _ .. _ .. __ . _ . _ 142 

PLATES --------------- --------------------------- ------------------. ---- -------------. ---- 14 7 

INDEX. -.... ---. --...... ---. -. --.. ------.- ---- ---- ------ " --- -- --. - -------- ---- ------.- --. . 2.51 

PLATE I. Sketch map of California, showing the principal fossilifero'.lS Tertiary localities._.. 7 

II. Pecten calkinsi n. sp. , P. landesi n. sp., P. proavus n. sp., and P. interradiatus 

Gabb ...................................... _ ................ ___ .. _______ .. ___ . 14!J 

III. Pecten clallamensis n. sp., P. waylandi n. sp., P. peckhami Gabb, P. branneri 

n. sp., and P. sanctrecruzensisn. SP--------------------------------------------- 151 

IV. Pecten carrizoensis n. flp. and P. coalingaensis n. sp ... ___ . _____ . _____ . ___ . _. __ . ___ • 153 

V. Pecten keepi n. sp., P. dilleri Dall, and P. sespeensis var. hydei n. var __ . _ __ _ _ _ _ _ _ 155 

VI. Pecten keepi n. sp. and P. coosensis Shumard ____ ... ___ . ____ .. ____________ . __ .. _ _ 157 

VII. Pecten propatulus Conrad and P. coosensis Shumard ........ _ ... _ .. ___ ._ .... __ .___ 159 

VIII. Pecten oweni n. sp. and P. sespeensis n. sp ... __ .. __ ...... ______ ............ _ _ _ _ _ _ 161 

IX. Pecten propatulus Conrad ....... _____ . ____ ... ___ .. ______ . ____ . __ ._ ... _ .. _________ 163 

X . Pecten fncanus Dall and P. wattsi var. morani n. var _ ..... ____ .................. _ 165 

XI. Pecten wattsi n. sp., P. hamlini n. sp., P. nutteri n,. sp., and P. crassicardo 

Conrad var. hamiltoni n. var .. _ ..... _. __ ..... ___ . _. __ . _. ____ . ____ ....... _ ... _ _ _ 167 

XII. Pecten bowersi n. sp . _ ................... __ ... _ . __ ... __ ..... ____ .. ___ ... _ . _ ... _ _ 169 

XIII. Pecten bowersi n. sp ..... _ .......... __ .. _ ..... __ . _. _ ....... _ .. ___ ... _ ... _ ... ___ . 171 

XIV. Pecten perrini n. sp ............ _ .. _ .. _ .. __ ............ _____ .... _ . _ ... _ ......... _ 173 

XV. Pecten perrini n. sp. and P. neahensis n. sp ............ _. ____ ... _____ .. .. .. .. .. .. 175 

XVI. Pecten crassicardo Conrad .... _ .... _ .... __ ·-.. _ ............... _ ...... _ ..... _. _. _.. 177 

X VII. Pecten crassicardo Conrad .......... __ .. ___ ... _ . _ ... __ ... __ . _ ... __ . _ .... _ . _ . __ . . . 179 

XVIII. Pecten crassicardo Conrad .................................. __ ............ .... __ .. 181 

XIX. Pecten estrellanus Conrad ..... _ ..... _ . ____ .. _ .............. __ ......... _ ....... _ _ _ 183 

XX. Pecten estrellanus Conrad and P. estrellanus Conrad var. catalinre n. var .. . ..... _ _ _ _ 185 

XXI. Pecten estrellanus Conrad ..... ___ . ____ ... ___ .. ___ ._ .. _ .. ___ . ____ . __ . _ .. . .. _._____ 187 

XXII. Pecten miguelensis n. sp ........... _ .... ___ .. ______ . _ ... _ .. _ ... _ .... ___ .. ____ . __ . 189 

XXIII. Pecten miguelerisis n. sp., P. estrellanus Conrad var. terminus n. var., P. vaughani 

n. sp., P. stanfordensis n. · sp., and P. lompicoensis n. sp .......... _ ........ _ .. _... 191 

XXIV. Pecten magnolia Conrad .... _ .. ___ .... _ ..... ~ __ .... __ .... __ .. ____ .. __ .. __ • . .. . . .. 193 

XXV. Pecten magnolia Conrad, P. cerrosensis Gabb var. mendenhalli n. var., and P. 

eldridgei n. sp ... _ ........ __ .............•....................•...••••.•••.. _ . . 195 
6 CONTENTS .AND ILLUSTRATIONS. 

Page. 

PLATE XXVI. Pecten deserti Conrad, P. andersoni n. sp., and P. andersoni var. barkerianus 

n. var .. __ .............. ____ . ___ ....... _ .............. _ . ______ . _ . ___ .. _ _ _ _ 197 

XXVII. Pecten discus Conrad, P. pabloensis Conrad, and P. lompicoensis n. sp .. __ . _.. 199 

XXVIII. Pecten lompocensis n. sp. and P. pedroanus Trask._ ...... _ .......... ___ . ____ . 201 

XXIX. Pecten ( Hinnites) giganteus Gray ...... . .......... __ .. _ ......... ______ . . . . . . 203 

XXX. Pecten meniami n. sp ______ .... __ _ _ _ _ __ _ _ _ __ __ .. ______ . __ : _____ . ___ ... _... 205 

XXXI. Pecten bell us Conrad ...... ___ ... _ ...... __ .... _ . _ .. ___ ........... __ . ____ . . . . 207 

XXXII. Pecten stearnsii Dall .. _ .. : . ___ .... __ .. __ .. ___ . _ .. _ ......... . ___ .... _ .. ____ . . . 209 

XXXIII. Pecten vogdesi n. sp., P. auburyi n. sp., P. hemphilli Dall, and P. lecontei n. sp. 211 

XXXIV. Pecten vogdesi n. sp., P. auburyi n. sp., P. purisimaensis n. sp., and P. turneri 

n. sp .... _ .. ___ ....... . __ ... __ .... ___ . _ ........... _ ............ ___ ....... _ 213 

XXXV. Pecten puril:!imaensis n. sp. and P. turneri n. sp ........... _ . . .. _____ . ___ ... _. 215 

XXXVI. Pecten healeyi n. sp .. __ ... ______ ~ . ____ .... __ . ______ . ___ ....... __ ~ ...... __ .. 217 

XXXVII. Pecten healeyi n. sp _. _____ . _. __ .. ____ ...... _ .. ___ ...... ____ .... _. _ ... . ___ .. 219 

XXXVIII. Pecten caurinus Gould .... _. ___ ... _ ..... ___ ... _ . _ ... _ .... _ ........... ____ ... _ 221 

XXXIX. Pecten caurinus Gould and P. paucicostatus Carpenter ... __ ........... ___ ... _. 223 

XL. Pecten veatchii Gabb _ .. ________ .. ___ . ____ ..... __ .. _ ... _ ... __ . _. _ ... _. _ .. _. _ 225 

XLI. Pecten parmeleei Dall, P. opuntia Dall, P. bartschi n. sp., P. hastatus Sowerby, 

and P. bellilamellatus n. sp _______ . ___ .. _ ........................ ___ ... _.. 227 

XLII. Pecten hastatus Sowerby and P. circularis Sowerby ... _ .. _ .... _ ..... __ .... __ . _ 229 

XLIII. Pecten hastatus Sowerby var. navarchus Dall, P. hastatus Sowerby var. hindsii 

Carpenter, and P. hastatus Sowerby var, hericius Gould .. ____ .... _ ....... ___ 231 . 

XLIV. Pecten jo:rdani Arnold, P. hastatus Sowerby var. strategus Dall, P. eerrosensis 

Gabb, P. circularis Sowerby, and P. riversi n. sp. __ ...... __ .... _. _......... 233 

XLV. Pecten islandi.cus Muller, P. washburnei n. sp., and P. lawsoni n. sp .. ___ ... __ . 235 

XLVI. Pecten excavatus Anton, P.latiauritus Conrad, P. latiauritus Conrad va~. monotimeris Conrad, P. latiauritus Conrad var. cerritenl"is n. var., P. latiauritus Conrad 

var. fucicolus Dall, and P. latiauritus Conrad var. delosi n. var .... _ .... __ . _ _ 237 

XL VII. Pecten ashleyi n. sp ________ . _____ . _____ .. ____ .. _ ........... _ .. _ . __ ........ _ 239 

XLVIII Pecten ashleyi n. sp., P. randolphi Dall, and P. randolphi Dall var. 'tillamookensis 

n. var .. __ . _____ ... _____ . ____ . _ . ___ .. _ .............. __ ... _ . _ .. .. ....... _ -.. 241 

XLIX. Pecten cerrosensis Gabb and P. cooperi n. sp. ____ ......... _ ....... _ ... _ .... _.. ~43 

L. Pecten circularis Sowerby var. requisulcatus Carpenter, P. palmeri Dall, and P. 

da v1dsoni Dall _ .. __________ . ________________ . ___ ............... __ . _ . . _ . . . 245 

Ll. Pecten diegensis Dall ____ . _ . _________ . ____ . ___ ..•.. ~ . __ . _ .... ____ ....... ___ . 24 7 

LII. Pecten subnodosus Sowerby, P. hastatus Sowerby var. albidus Dall n. var., and 

P. vancouverensis Whiteaves. ___ . ________ . ____ . _. _. __ . ___ . _. __ ... ___ .. _ .. _ 249 

LIII. Pecten subnodosus Sower by and P. alaskensis Dall ... __ .. _ .. _. ___ . ... - __ . __ . _. 251 

FrG. 1. Pecten circularis Sowerby var. requisulcatus Carpenter; right valve, exterior._. 45 

2. The same; right valve, interior ... _. ____ . ______ . _. _ .... ______ .. __ .. ------.... 46 

U . S .GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL.I 

llG us' 114. 

~~~~~~ ~ ~~~ ~~~~~~ ~~~ ~~~ Jl~~;J/7--l---~~-- ----~~~~----FOSSILIFEROUSTERTIARYLOCALITIES PARTIAL LIST OF :;1 4-e" 

\ / . 0 COW<R , ... ., -"-- ~~ ... :'"~~·."! ........ ':'~";; ,(\.··· 'MARTON 'Z..----------·-······----·CO NTRA COUA 

r-----------~--------

0 

M AP OF 

CALIFOR.NI.A .. SHOWING PRINCIPAL TE RTIAl{Y AND ~7 

PLEISTO "'E FOSSILIFEROUS LOCALITIE S 

33, I. 'he r·ed dots ?jrukcate ross"(liferowc; localia~s 07' 7 ·t;g U(ns. 

Thecorr el.a:tWns agree widv the correlatwn table at tJw t.ext o.nd are tentative. 

Scale 

2e5=3:::I:ii::::.= ::i 25~===3:'==~=="'="~wtl rn iles 

12:i 121 ~ 

. \ ; · ~ ;~~Jt{~ElNH{HH{~ f~ff~~i~~; ,~j:~"i~~~ 

Sa lemente l 

N 

\ 

EOCENE ( TE.JO N } 

: ~~~ ~~ ;o~~J~=&~~" "~~ ~~ ~ ~~~~J_-_:- :::::::::::: K~RN 10 MARY SVILLE BU TTES ·-- - - ----------------SUT T E R 

11 MERCeD FALLS- --- - --------------- - ----- MERCED 

12 SO MER S VILLI!;._---- - ---------- --- CON TRA COS'f.O. 

g ~ff~~5~~:~ ~~~~~~~~~~~~=~~~~~~~~ ~;jf.~~~! 41. '7 l " ,J O LLA --- --- --------------- · - -·- 8AN DIEGO 

1• SAN LO AEN~~ :~!'R~~~ ~~ ~~ ~~ )SANTA C RUZ 

;~ :~ ~~ o,~=~ ~~ ~~~ ~~;:~ ~?;: ~~~ ~co N;:: ~~;;~ 

~~1~!i:~1]~fff~~~ ;;~c~·;~;;~!j~~ 29 PAS .... D!:N"·------ ------------ - -- 1.05 A N GEL!: $ 

SO IEL TORO -- --- - -------- -- - -- --- O AA.NGE 

31 C A A RIZO RE~~~~ .:~ ·( ~~~ ;;~.;) • -- '!i AN DIEGO 40" 

32 P!NOLE--------------------- -- CONT RA COST" 

38 t.. A HG L EY HI LL - -· - --- · - ------- --· •• SAN "'"TEO 

a• C ASTLE ROCK AJDGI!: ------------ - -- S ANTA C LARA 

S& B E N L O M O N D AND FELTON --- ---·· •• - S ANTA C RUZ 

86 C"RMIELO VA LU:Y --- - --- - ------ -·----- MONTEREY 

i~ Jj£ff~~~~~;~:~~:;~-:~~~~:-_~_: SAN CU" :::~~~ ~ 4 1 ARROYO GRAPII OE- ---------------. 

• 2 M c KITTRICK DISTRIC T ----------·_ --·-- · ---KERN 

4 3 S AN PEDRO • ••• ----------- - --- - ••• L.O S ANGELES 

M IOCEN E lSAN PABLOJ 

4~ S AN PABLO 8A'1'-------- - - - -------- CONTRA COST A 

4~ W A L I'IUT CREEK------ - ----- --- --- -· u " 

~ !~~T: :;A~o~l! _: ! : : .-::::_- _-:_-_-_-_-_- _- :_-_- _- s---:;:T~:~ ~ 48 SAN AROO --- •..•••• -- ·- • '" 

4 $ CO ... LINOA - ------ ---- -- - - --- --- ·- FRESNO 

~0 8 ANT" M"RGA RITA . -------------- - .SAN LUIS OBISPO 

51 IESTRELL " --- - --- - - --- ----- -- •4 

~2 S"NT" CATAliNA ISL.A HD-- ---- -- ---- --- 1..0S A NGEt.ES 

PLI OOENE ( P U RIS IMA) 

~a· CAE&CEriT CITY- ----- --------- --------- D EL NO RTE 

;; :~~~ e7~vAE.~-(~~o--o~~~---·_:_-_ _-_- _-_-_- ___ s;~ M!~~~~ !5&PE9CAD£AO ------- ----- .-- ... ---- --· " 

7 PORTO LA VAL LEY ·- ---- ----------- .--- <• 

58 MOUTH O F STEVE N S CREE l< .---•• --.-. - - . SANTA CLARA 

5 11 SO QU EL CREEl< - ----------· ··---- -- - SANTA CRUZ 

60 CMOLAME VALLE:Y.-------------- --- • • - - M O NTEREY 

61 LEWI S CREEK- ---- - -------- - - ----------

62 PR IE ST VAL LEY-- --- --- - ---------- -- ---

4!1:!1 CA6 J<I ALIA- - -------------------- -- SANTA BARBARA 

4!14 TEMESCAI. C AN YON ----- - ---- - '-- •• · LOS AN GELE S 

IS LOS ANGELES . - - ------- - ---------- -- '' 

16 FERN ... NOO TUNNEL ------ - - - ---- -- · - "' 

67 OLINDA (PUENTE HILLS} ••••• -------- -- " 

P LIOOE N E ( MERO EO} 

68 LAI(£ MERCED BLUFF S ------- - - -- .----. SA N '-4ATEO 

4!19 A~O NUI!:V O C REI!:I( . ---------------- " 

70 I'I!LT I. Ato:E T~ Nr ORO UN lV[RSITY) -~ ~ •. ~NTA CI." R~ 

1 1 C APIT OLA - --.-------- -------- ----. S A N TA CRU Z 

72 SA N T/>. BAI;IBARA.-- -- ------------- - SANTA BARBARA 

~: !:: T~~::~-~ ;~~~ ~~ -~~ --_-_-:-_·_-:__-_-_-_-_---- -~~-· ;~ ~:2:~~ PLE I S TOCEN E (sAN P E DRO} 

~ SANTA CRUZ - - - ----- - -- •• - --------- - S ANT" C RU Z 

7 1 SUMMI!:RLAN O ••• _ - - - . • - ••.• - -- · S ... NTA B ARBARA 

781.0N G BE ... CH --------- -- - ---- - -- - - -- 1..0& AN GEI...I!:S 

~~ ::~= R~ E~~~ · ::: : :::~ :::: ::::: _·: - -- A~':. :!~ &TSPAN ISI-I B IGH 'r--- --------------------- " " 

\:-/ 0 ., _ 

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I 

• 

THE TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

By RALPH ARNOLD. 

INTRODUCTION. 

· This paper consists of two parts. The first is a brief outline of the different 

Tertiary and Pleistocene formations of California, giving the type localities, where, 

when, and by whom first described, their salient characters, where they and their 

supposed equiyalents are known to occur, the species of P ecten found in them, 

and their typical fauna as far as known. The second is devoted to the description 

and illustration of all of the known Tertiary, Pleistocene, and Recent Pectens of 

the western coast of North America from Alaska to and including the Gulf of 

California. With the description of each species is also given an account of its 

geologic and geographic range and, where practicable, its associated fauna. 

This particular genus was chosen for study because of its great value for the 

stratigraphic determination of the Tertiary formations of the west coast and 

because of the large amount of material available at the time the work was 

undertaken. The genus is admirably adapted to purposes of correlation because 

of (a) its oecurrence in every important Tertiary horizon in California, (b) the 

limited vertical and wide geographic range of most of its species, and (c) the 

comparatively simple yet salient characters which mark the different species. 

The present paper is a larger and more comprehensive one than was contemplated when the work was first begun. The original plan was simply to monograph 

only the fossil Pectens of California, but as the work progressed it soon became 

apparent that the original subject could be thoroughly treated only by a more 

or less detailed consideration of the fossil Pectens of the adjacent territory and 

the living members of . the genus found along the whole western coast of North 

America. To give the paper its greatest possible value, it became necessary to 

define as accurately as possible the stratigraphic and geographic range of each 

species; and in order to do this consistently an examination of all of the availahle 

marine Tertiary paleontologic material from the west coast was undertaken. Then, 

that the data thus obtained might be made more available and that the relations 

of the different faunas and horizons of the California Tertiary might be the more 

clearly set forth, it was· deemed advisable to include a brief outline of the characteristics, geographic range, and faunas of the different Tertiary formations. 

It was obvious that any scheme of classification of the Pectinidce based wholly 

upon specimens from the Pacific coast would necessarily be disconnected and unsatisfactory. It seemed advisable, therefore, to adopt so,me system which was founded 

7 
8 TERTIARY .AND QUATERNARY PECTENS OF CALIFORNIA. 

upon material from a much wider geographic range. Doctor Dall's classification 

of the famHy, given in his "Tertiary Fauna of Florida," not ·only fulfilled this 

requirement, but had the added desirability of being based partly upon a considerable amount of west coast Tertiary and living material. Dall's classification, with 

but slight alteration, has, therefore, been adopted for this paper. 

Collections belonging to the following institutions and individuals we:a;e exam. 

ined by the writer during the preparation of this report: 

United States Geological Survey, W ashjngton. 

United States National Museum, Washington. 

Leland Stanford Junior University, California. 

University of California, Berkeley. 

California Academy of Sciences, San Francisco. 

California State Mining Bureau, San Francisco. 

Academy of Natural Sciences, Philadelphia. 

American Museum of Natural History, New York. 

State Museum, Albany, N. Y. 

Mrs. T. S. Oldroyd, Long Beach, Cal. 

Mrs. M. B., Williamson, Los Angeles, Cal. 

Miss L. J. F. Hecox, Santa Cruz, Cal. 

Mrs. Blanche Trask, Avalon, Los Angeles County, Cal. 

Mr. F. L. Button, Oakland, Cal. 

Dr. J. J. Rivers, Santa Monica, Cal. 

Mr. J. Howard Wilson, Yonkers, N. Y. 

Dr. Stephen Bowers, Los Angeles, Cal. 

Dr. L. G. Yates, Santa Barbara, Cal. 

Mr. Clark Smith, Paso Robles, Cal. 

Mr. Delos Arnold, Pasadena, Cal. 

The writer is indebted to Dr. 'Vm. H. Dall, of the United States Geologica[ 

Survey, for kindly assistance and helpful suggestions given during the preparation 

of this paper. In addition to those already mentioned, the writer wishes to extend 

his thanks to the following for assistance and courtesies extended: Dr. J. C. Branner, 

Dr. J.P. Smith, Dr. J. C. Merriam, Dr. T. W. Stanton, Mr. Edward Hoitt Nutter, 

Prof. J. ~I. Hyde, Mr. G~ H. Eldridge, Mr. Homer Hamlin,- Dr. T. Wayland 

Vaughan, Dr. Paul Bartsch, Mr. L. M. Loomis, Mr. F. M. Anderson, Mr. Lewis 

E. Aubury, Dr. H. W. Fairbanks, Dr. H. A. Pilsbry, Mr. C. W. Johnson, and 

many others. 

The illustrations are, with the exceptions noted in the explanations, half-tone 

reproductions of retouched photographs. To give an even color effect, the Williams 

process of coating the specimen was used on most of the specimens before photographing. My acknowledgments and -thanks are due to l\Hss M. K. Sumner, 

Miss Maude Baggett, Miss Marian Page, and Mr. H. C. Hunter, artists; to Mr. 

E. M. Bane, photographer; and to Messrs. J. L. Ridgway and N. W. Carkhuff, 

chiefs, respectively, of the sections of illustrations and photography, for the very 

satisfactory execution of the drawings . 

• 
• 

PART I. 

TERTIARY AND PLEISTOCENE FORMATIONS OF CALIFORNIA. 

POST-CRETACEOUS GEOLOGIC COLUMN. 

The process of marine sedimentation has been going on at one place or another 

within the California province almost without interruption since .,---·---- - · 

the beginning of the Cretaceous, and as a result the greater por- .8 aSj ·8 ~ San Pedro, 1,000' ± . 

tion of this long period is represented by formations which p:;'"' 

outcrop over much of the territory between the Sierra Nevada !- ----- -

mountain range and the Pacific Ocean. The only great break 

in the record, as shown by the faunas of the different forma- o.i 

tions, is that between the Tejon (Eocene) and its overlying beds. ~ 

Merced, 5,000' ± . 

Each of the other formations is more or less closely related ~ ......... ....................... . 

faunally to those immediately above or below, where the formations are of a more or less similar lithologic character. 

The stratigraphic relations between adjacent formations yary 

in different localities. At one place two formations may be 

separated by~ marked unconformity, while at another locality, 

only a comparatively short distance away from the first, the 

San Pablo, 1,500-2,000'. 

same formations may rest in an apparently conformable posi- o.i 

tion with relation to each other. In general, however, the ~ Monterey, 2•

500' ±. 

relations existing between the different formations is that indi- :il .................................... . 

cated by the accompanying diagram of the California postCretaceous column. 

POST-CRETACEOUS CORRELATION TABLE. 

The following correlation table of the principal marine 

Tertiary and Pleistocene formations of California, together 

with a brief outline of the typical ones, is tentative and based 

Vaqueros,S,OOO' ± . 

---· 

o.i J 

~ 1 San Lorenw, 2,300' ± .. 

on the information at hand at the beginning of 1905. Further 

study will doubtless add many new formations to the list, 

some of which may represent horizons different from those ~ Q) 

Tejon, 4,000' +. 

of the known divisiong, but the relative position of those ~ 

already known is probably about as indicated in the table. 

· The faunal lists given under each formation comprise the 

species found at the type locality of the formation, and, in 

addition, such other species as are found in beds which have 

been quite definitely correlated with the latter. These correlations are necessarily very broad and are intended only to 

indicate in a general way the contemporaneity of the strata 

in question. The names used in the lists of fossils are those 

commonly applied to the respective species by the west coast 

paleontologists. Owing to the imperfect state of our knowledge 

:Martinez, 1,000-2,000'. 

Chico (Cretaceous). 

The Tertiary and Pleistocene column of California. 

Total thickness, 21,000 feet+. 

NOTE. -Full lines represent unconformity; broken 

lines, conformity. · 

regarding the nomenclature of the California Tertiary fauna, there is a probability 

' 9 
10 TERTIARY AND QUATERNARY PEOTENS OF CALIFORNIA. 

that some of the names used are erroneous. The writer, therefore, reserves the 

privilege of revising any of the names should future studywarrant it. 

A tentative correlation table of the principal marine Tertiary and Pleistocene formations of California to 1905. 

Epoch. Oregon and Wash- Northern and Central Salinas and Southern Southern California. ington. California . San Joaquin valleys. 

. Pleistocene. Coos conglomer- San Pedro formaate. a tion. 

{Merced formation. Paso Robles formation. 

"Wildcat forma- Deadman Island 

Mytilus beds. a tion.'' Pliocene. 

Pliocene. San Diego formation. 

{ 

{ Purisima formation. Cholame Valley 

Transitional. beds. 

Sooke beds. a San Pablo forma- rismo formation. 

Empire beds. a }catalina Miocene. tion. 

Santa Margarita , formation. 

Contra Costa Coun- Carrizo Creek 

ty Miocene. beds(?) 

Miocene. Astoria sand- Monterey shale. Monterey shale. Monterey shale. 

stone. a 

Vaqueros sand- Vaqueros sand- Pasadena Miocene. 

stone. stone. 

Tunnel Point 

beds. a San Lorenzo forma- Oligocene. Astoria shales. a I tion. 

Aturia bed. a 

Eocene. Arago formation. a Tejon formation. Tejon formation. Tejon formation. 

Puget group. a Martinez formation. Rock Creek Eocene. 

aDall, W. H., North Am. Tertiary horizons: Eighteenth Ann. Rept. U.S. Geol. Survey, 1898, pt. 2, pp. 323-343. 

N OTE.-The author disclaims responsibility for those names in the above table which he does not discuss in this paper. 

EOCENE. . . I 

At least two horizons are recognizable in the Eocene of the west coast, viz, 

the Martinez and the Tejon; and there may also possibly be a third, which is 

represented by the richly fossiliferous beds exposed in the vicinity of Little Falls, 

Lewis County, Wash. The last-mentioned horizon is probably above that of the 

Tejon, although its relative position has not as yet been carefully worked out. 

On account· of the lack. of definite information concerning the affiliations of- its 

fauna, the Little Falls beds will be included in the Tejon. The separation of the 

Martinez and Tejon · formations is based principally upon paleontologic evidence, 

there being no apparent unconformity between them, although their lithologic 

characters are usually so mew hat different. 
... 

I . 

EOCENE FORMATIONS. 11 

MARTINEZ FORMA170N. 

TYPE LOCALITY. 

The type locality is south of the town of Martinez, Contra Costa County, Cal. 

NAME AJ\D DESCRIPTION. 

This formation was named and described by J. D. "\Vhitney in California 

Geological Survey, Paleontology, vol. 2, 1869, preface, p. xiii. 

DEFINITION. 

Dr. J. C. Merriam, in his paper on "The geologic relations of the Martinez 

group of California at the typical locality,"a gives the following definition of the 

lVIartinez formation, which is generally accepted by paleontologists and geologists: 

"The lVIartinez group, comprising in the typical locality between 1,000 and 

2,000 feet of sandstones, shales, and glauconitic ~:lands, forms the lower part of a 

presumably conformable series, the upper portion of which is formed by the Tejon. 

It contains a known fauna of over sixty species, of which the greater portion is 

peculiar to itself. A number of its species range up into the Tejon, and a very few 

long-lived forms are known to occur also in the Chico (Cretaceous). Since the 

Martinez and Chico are faunally only distantly related, it is probable that an unconformity exists between them. Though satisfactory correlation of California formations with the subdivisions of the standard geological scale can be accomplished only 

when the local scale is fully worked out, we may, for the present at least, accept 

Mr. Stanton's correlation of the Martinez with a portion of the Eocene." 

LOCALITIES. 

Martinez, Clayton, Pacheco, and Army Point (near Benicia), Contra Costa County. 

Lower Lake, Lake County. 

Between headwaters of Pescadero Creek and San Lorenzo River, San Mateo County (?). 

Rock Creek, Los Angeles County. 

Point Lorna, San Diego County (Eocene here m.ay include the Martinez). 

FAUNA. 

Pecten .fauna.-The Pecten fauna of this horizon consists, so far as known, 

of only one species, P ecten ( Ohlamys) p 'roavus n. sp., and this from a locality of 

doubtful Martinez age. 

a jour. Geol., vol. 5, p. 775. 
12 TERTIARY .AND QUATERNARY PECTENS OF O.ALIFORNIA. 

The fauna of the Martinez consists essentially of the followmg species: 

List of .1lfartinez formation (lower Eocene) fossils. a 

[Those species followed by (L) are found in the lower beds at Martinez; those by (U), upper beds at Martinez; those 

by (,B), bed& at Benicia; those by (C), beds at Lower Lake; and those by (P) outcrop on ridge between headwaters of 

San Lorenzo River and Pescadero Creek, San Mateo County.] 

FORAMINIFERA. 

Foraminifera nummuloid (U). 

Foraminifera, 3 sp. indet. ( L). 

ANTHOZOA. 

Flabellum remondianum Gabb (LBO). 

Trochocyathus zitteli Vaughan (L). 

ECHINOIDEA. 

Cidaris (?) spmes (P). 

Schizaster lecontei Merriam (LU). 

BRACHIOPODA. 

Terebratulina tejonensis Stanton (BOP). 

Tereb:ratula (?) n. sp. (P). 

PELECYPODA. 

Area biloba Weaver (LU). 

Cardium cooperi Gabb (LU). 

Crassatellites unioides Stanton (C). 

Cucullrea mathewsonii Gabb (LUBC). 

Glycymeris veatchii Gabb var. major Stanton (C). 

Leda alreformis Gabb (BC). 

Leda gabbi Conrad (LUC). 

Lima multiradiata Gabb (C). 

Meretrix sp. (LB). 

Modiolus merriami Weaver (LU). 

Modiolus ornatus Gabb (UC). 

Nucula truncata Gabb (LUB). 

Ostrea ( cf.) idriaensis Gabb (P). 

Pecten proavus n. sp. (P). 

Phacoides turneri Stanton (C). 

Pholadomya nasuta Gabb (LUB). 

Plicatula ostreiformis Stanton (C). 

Semele (?) n. sp. (P). 

Solen parallelus Gabb (0). 

Solen stantoni Weaver (U). 

Tapes (aff.) quadrata Gabb (LB). 

Tellina requalis Gabb (C). 

Tellina hofftnanniana Gabb (C). 

Tellina martinezensis Weaver (LU). 

Tellina hornii Gabb (UC). 

Tellina undulifera Gabb (UB). 

Teredo sp. ( L). 

Thracia karquinesensis Weaver (U). 

V enericardia planicosta Lamarck var. hornii 

Gabb (U). 

GASTEROPODA. 

Actreon lawsoni Weaver (LB). 

Ampullina (cf.) striata Gabb (UBC). 

Architectonica tuberculata Weaver (U). 

Brachysphingus liratus Gabb (UBC). 

Bullinula subglobosa Weaver (U). 

Cerithiopsis alternata Gabb (C). 

Cylichna costata Gabb (LC). 

Dentalium cooperi Gabb (LUC). 

Dentalium s ramineum Gabb (U). 

Disco helix californicus Weaver ( L). 

Ficopsis angulatus Weaver (U). 

Fusus requilateralis Weaver (L). 

Galerus excentricus Gabb (C). 

Helcion ( cf.) dichotoma Gabb (P). 

Heteroterma gabbi Stanton (UC). 

Heteroterma striata Stanton (C). 

Heteroterma trochoidea Gabb (U). 

Heteroterma, indet. (U). 

Lunatia hornii Gabb (C). 

Megatabennus (?) n. sp. (P). 

Megistostoma striata Gabb (U.) 

Morio tuberculatus Gabb (U). 

Natica sp. 

Neptunea mucronata Gabb (L). 

Perissolax blakei Conrad (B). 

Perissolax tricarnatus ·weaver (LUBC). 

Serpula (?) sp. (LP). 

I Siphonalia lineata Stanton (LUC). 

Strepsidura pachecoensis Stanton (U). 

Tritonium ( cf.) californicum Gabb (P). 

Tritonium eocenicum Weaver (U). 

Tritonium impressum Weaver (U). 

Tritonhnn pulchrum Weaver (U). 

Turbinella crassitesta Gabb (L). 

Turritella conica Weaver (U). 

Turritella infragranulata Gabb (UBC). 

Turritella martinezensis Gabb (L). 

Turritella pachecoensis Stanton (U). 

Turris sp. indet. ( U). 

Urosyca caudata Gabb (LUBC). 

Urosyca robusta Weaver (L). 

Xenophora zitteli Weaver (L). 

CRUSTACEA. 

Cance-r ( U). 

Crustacean remains, macruran (U). 

a Compiled from lists· by Merriam, J. C., Jour. Geol., vol. 5, 1897, p. 773; Stanton, T. W., Seventeenth Ann. Rept. 

U.S. Geol. Survey, pt. 1, 1896, p. 1025; and Weaver, C. E., Bull. Dept. Geol., Univ. of Cal., vol. 4, 1905, No.5, pp. 110-111. 
• 

EOCENE FORMATIONS. 13 

TEJON FORUATIO ... ¥. 

TYPE LOCALITY. 

The type locality is in the region about Fort Tejon, Kern County, Cal. 

NAME .AND DESCRIPTION. 

This formation was named and described by J. D. Whitney m California 

Geological Survey, Paleontology, vol. 2, 1869, preface, p. xiii. 

DEFINITION. 

The original definition and description of this formation is as follows: 

""The Tejon group * * * the division B of Paleontology, volume 1, is peculiar 

to California. It is found most extensively developed in the vicinity of Fort Tejon 

and about Martinez. From the latter locality it forms an almost continuous belt 

in the Coast Ranges to Marshs, 15 miles east of Mount Diablo, where it sinks under 

the San Joaquin plain. It was also discovered by the different members of the 

Survey at various points on the eastern face of the same range as far south as New 

Idria, and in the summer of 1866 by Mr. Gabb in Mendocino County, near Round 

Valley, the latter locality being the most northern point at which it is as yet known. 

-: ;. * *" 

"This group contains a large and highly characteristic series of fossils, the 

larger part peculiar to itself, while a considerable percentage is found extending 

below into the next group (Martinez) * * * " 

LOCALITIES. 

Fort Tejon, Uvas Pass, and San Emidio, Kern County. 

Marysville Buttes, Sutter County. 

Merced Falls, Merced County. 

Martinez, Somersville, Clayton, and Marshs, Contra Costa County. 

Kew Idria and Griswold, San Benito County. 

Coalinga and San Joaquin coal mines, Fresno County. 

North side of Sisar Valley, Ve~tura County. 

North side Santa Ana Mountains, 4 miles south and 5 miles northwest of Corona, Riverside 

County. 

San Luis Rey to San Diego, Rose Canyon and Point Loma Peninsula, San Diego County. 

Peninsula of Lower California, latitude 29° 301 • 

Port Crescent, Clallam County; Little Falls, Lewis County, and Oakville, Chehalis County, \Vash. 

(Landes and Arnold). 

In Oregon at the following localities, according to Diller (1896): 

Nehalem River, 5 miles east of Nehalem, and also midway between Jewell and Mishawaka. 

Wilson River toll road, 22 mile'S from Tillamook. 

Vineyard Hill, 4 miles north of Corvallis. 

Benson's and Rowe's, 5 miles north of Corvallis. 

Scott's, Cooper's, and Newton's, southwest of Corvallls. 

Roger's, in section 27, T. 13 S., R. 6 vV. 

Monroe, Comstock, Cleveland, Callahan's, and Camas, Douglas County. 

Near mouth of Little River, 20 miles northeast of Roseburg. 

Marshfield, Jordan Point, and Cape Arago, southward to near mouth of Coquille River. 
14 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

FAUNA. 

Pecten fauna.-The Pecten fauna of the Tejon group consists,. so far as 

known, only of three species, P. calkin8i n. sp., P. landesi n. sp., and P. interradiatus Gabb. The first two probably belong to the subgenus Ohlarnys, but are 

not closely allied to any - of the subsequent members of this group, so far as 

known. P. interradiatu8 belongs to the Propeamus~um group and appears to be 

the precursor of such forms as P. 8tanfordensis, P. waylandi, and P. clallamensi8. 

The following species have been found in the Tejon formation in different 

parts of California: 

List of Tejon formation (Eocene) fossils. a 

[Those marked with an asterisk (*) have been found at the type locality.) 

ANTHOZOA. 

Flabellum californicum Vaughan. 

Flabellum remondianum Gabb. 

Trochocyathus californicus Vaughan. 

Trochocyathus stantoni Vaughan. 

Trocr')cyathus striatus Gabb. 

PELECYPOD A. 

*Area horni Gab b. 

Astarte semideiltata Cooper. 

* Axinea cor Gabb ( =Glycymeris id. ). 

* Axinea sagittata Gabb ( =Glycymeris id. ). 

Barbatia morsei Gabb. 

*Cardium breweri Gabb. 

*Cardium cooperi Gabb. 

*Cardium ( Lrevicardium) linteum Conrad. 

Corbula alreformis Gabb. 

*Corbula horni Gab b. 

Corbula parilis Gabb. 

Corbula primorsa Gabb. 

*Crassatellites grandis Gabb. 

*Crassatellites uvasana Conrad; 

Donax latus Gabb. 

*Dosinia elevata Gabb. 

*Dosinia gyrata Gabo. 

*Leda gabbi Conrad. 

Lima multiradiata Gabb. 

Lucina? cretacea Gabb. 

*Meretrix californica Conrad. 

*Meretrix horni Gabb. 

*Meretrix ovalis Gabb. 

*Meretrix uvasana Conrad. 

*Modiolus ornatus Gabb. 

*Mysia? polita Gabb. 

*Mytilus ascia Gabb. 

PELECYPODA-COhtinued. 

*Mytilus humerus Conrad. 

*Nucula truncata Gabb. 

Ostrea appressa Gabb. 

Oshea idriaensis Gabb. 

*Septifer dichotomus Gabb. 

Solen ( Hypogella) diegoensis Gab b. 

Stalagmium concentricum Gabb. 

*Tapes conradiana Gabb. 

Tapes? cretacea Gabb. 

*Tapes? quadrata Gabb. 

*Tellina californica Gabb. 

*Tellina horni Gabb. 

*Tellina longa Gabb. 

*Tellina remondi Gabb. 

Unio penultimus Gabb. 

Venus requilateralis Gab b. 

*Venericardia planicosta Lamarck. 

*Venericardia planicosta var. hornii Gabb. 

GASTEROPODA. 

* Acmrea tejonensis Gab b. 

Amauropsis alocata Gab b. 

Ancilla ( Oliverato) californica Cooper. 

Ancilla elongata Gabb. 

* Architectonica cognata Gab b. 

* Architectonica horni Gab b. 

Bela clathrata Gabb. 

Bittium longissimum Cooper. 

Brachysphingus liratus Gabb. 

Brachysphingus sinuatrts Gabb. 

*Bulla horni Gab b. 

* Bullia ( Molopophorus) striata Gab b. 

Cancellaria irelaniana Cooper. 

Cerithiopsis alternata Gabb. 

aCompiled from lists by Cooper, J. G., Seventh Ann. Rept. California State Mineralogist, p. 271 et seq,; Cooper, 

J. G., Bull. California State Mining Bureau No. 4, p. 39 et seq.; Stanton, T. W., Seventeenth Ann. Rept. U. S. Geol. 

Survey., p. 1021 et seq.; Merriam, J. C., Jour. Geol., vol. 5, p. 771. 
OLIGOCENE FORMATIONS. 

List of Tejon formation (Eocene) fossUs-Continued. 

GASTEROPODA-continued. 

*Conus horni ·Gab b. 

*Conus remondi Gab b. 

Cordiera gracillima Cooper. 

* Cordiera microptygma Gabb. 

* Cyprrea (Luponia) bayerquei Gab b. 

Cyprrea (Epona) mathewsoni Gabb. 

* Dentalium cooperi Gab b. 

* Dentalium stramineum Gab b. 

Diodus tenuis Gabb. 

Drillia ullreyana Cooper. 

* Enspira alveata Conrad. 

* Fasciolaria io Gabb. 

Fasciolaria lreviuscula Gabb. 

* Fasciolaria sinuata Gabb. 

Ficopsis cooperi Gabb. 

* Ficopsis horni Gab b. 

Ficopsis remondi Gabb. 

* Fusus californicus Conrad. 

* Fusus diaboli Gab b. 

* Fusus martinez Gab b. 

Fusus supraplanus Cooper. 

Galerus excentricus Gabb. 

Gyrodes dowelli White. 

Loxotrema turrita Gabb. 

*Lunatia horni Gabb. 

* Lunatia nuciformis Gab b. 

Lunatia shumardiana Gabb. 

Mangilia saturalis Cooper. 

Margaritella 1Crenulata Gab b. 

Megistostoma striatum Gabb. 

Mitra cretacea Gabb. 

Mitra simplicissima Couper. 

* Morio (Sconsia) tuberculatus Gabb. 

Nassa antiquata Gabb. 

* Nassa cretacea Gab b. 

GASTEROPODA -continued. 

* Natica uvasana Gabb. 

* Naticina obliqua Gab b. 

Neptunea (Tritonofusus) cretacea Gabb. 

Neptunea? gracilis Gabb. 

Neptunea? supraplicata Gabb. 

Nerita (Theliostyla) triangulata Gabb. 

Neverita globosa Gabb. 

*Neverita secta Gabb. 

* Olivella mathewsoni Gab b. 

* Perissolax blakei Conrad. 

Pleurotoma perkinsiana Cooper. 

Potamides carbonicola Cooper. 

Potamides? davisiana Cooper. 

*Rimella canalifera Gabb. 

Rimella simplex Gabb. 

Scalaria ( Opalia) mathewsoni Gab b. 

*Siphonodentalium pusillum Gabb. 

*Spirocrypta pileum Gabb. 

*Surcula claytonensis Gabb. 

Surcula crenatospira Cooper. 

Surcula inconstans Cooper. 

Surcula monilifera Cooper. 

Surcula prreattenuata Gabb. 

Surcula raricostata Gabb. 

*Surcula sinuata Gabb. 

Terebra californica Gabb. 

Terebra wattsiana Cooper. 

*Tritonium californicum Gabb. 

Tritonium (Trachytriton) diegoensis Gabb. 

*Tritonium (Trachytriton) fusiforrne Gabb. 

*Tritonium horni Gabb. 

*Tritonium paucivaricatum Gabb. 

*Tritonium (Trachytriton). tejonensis Gabb. 

*Tritonium whitneyi Gabb. 

Turritilla martinezensis Gabb. 

OLIGOCENE. 

15 

The recognition of Oligocene strata on the western coast of North America 

has been more or less uncertain. Doctor Dalla has recognized what he considers 

to be an Oligocene fauna from seyeral localities in the northwestern part of 

Oregon, but as yery little detailed paleontologic work has been done in that 

section no adequate lists of the fossils are ayailable. Certain gray shales in the 

Yicinity of Porter, Chehalis County, Wash., and shales near Bean Point, King 

County, and along the Strait of San Juan de Fuea, on the north side of Clallam 

County, in the s.arne State, contain a fauna which may also be Oligocene. 

a Diller. J. S., Seventeenth Ann. Rept. U.S. Geol. Survey, pt. 1, 1896, p. 464 
16 TERTIARY AND QUATERNARY PECTENS OF OALIFOR.NIA. 

Within . the last five years strata have been discovered in the Santa Cruz 

quadrangle which contain a fauna representing a horizon probably lower than 

any of the known lower Miocene horizons of California. The faunal relations 

and stratigraphic position of this new formation have led the writer to believe 

that it belongs in the Oligocene. 

With the exceptions a"Qove noted, no marine Oligocene has heretofore been 

recognized on the west coast north of that found in the Central American States. 

SAN LORENZO FORMATION. 

TYPE LOCALITY. 

The type locality is on San Lorenzo River, 2t miles· above the town of Boulder 

Creek, Santa Cruz County, Cal. 

DEFINITION. 

The San Lorenzo formation consists essentially of a series of grayish ''muddy" 

shales and fine sandstones, which are typically exposed along the bed of the San 

Lorenzo River, about 2 miles above Boulder Creek, Santa Cruz County. The 

formation extends westward from the type locality into the Big Basin, on the 

north side of which it rests conformably against the older yellowish sandstones 

(pos~~;ibly Oligocene in age) of the B-qtano Ridge. To the southeast of the exposures 

on San Lorenzo River the formation, in the shape of a broad anticlinal nose, 

gradually dips conformably under the sandstones and conglomerates of the lower 

Miocene. The approxit'nate thic~ness of the formation in the vicinity of the 

type locality is about 2,300 feet. 

LOGALITIES. 

San Lorenzo River, Boulder Creek, Kings Creek, Twobar Creek, Bear Creek, and Love Creek, 

all near the town of Boulder Creek, Santa Cruz County. 

FAUNA. 

The fauna of the San Lorenzo formation consists, for the most part, of forms 

best suited by the conditions prevalent during the deposition of sandy shales. In 

other words, it is a moderately deep-water fauna. It shows several species found 

in the Monterey shale, but it also contains many species which appe~r to be 

closely related to Tejon (Eocene) forms. Bearing in mind these faunal relations 

and the stratigraphic position of the formation, it ·appears probable that it belongs 

in the Oligocene. . 

Pecten fauna.-In this horizon we meet with the common Miocene Pseudamusium, P. peckhami, . and characteristic representatives of Pecten s. s. and 

Ohlamys, the groups which are so well represented in the later formations. P. 

(Pecten) sanctcecruzen.sis is quite elosely allied to P. bell/us and P. hemphilli, which 

are found in the Pliocene, while in the top of the formation, associated with a 

transitional Oligocene-Miocene fauna, is P. ( Ohlamys) branneri, the analogue and 

probable precursor of P. islandicus, and the latter's related forms. P. clallamensis 

and P. waylandi from the Oligocene-1\fiocene series of Washington should also 

probably be included in the Oligocene fauna. 
MIOCENE ..I!'ORMATIONS. 17 

The following species have been found in the San Lorenzo formation at the 

type locality, or within a radius of four or five miles from it: 

List of San Lorenzo formation ( Oligocene) fossils. 

[Those marked with an asterisk (*) have been found at the type locality.] 

BRACHIOPODA. 

Terebratula cf. nitens Conrad. 

PELECYPOD A. 

Area sp. A. 

* Callista angustifrons Conrad. 

Callista sp. A. 

Cardium ( cf.) breweri Gabb. 

Cardium (Lrevicardium?) n. sp. 

Corbula sp. A. 

Cytherea ( cf. ) vespertina Conrad. 

Cytherea sp. A. 

Leda, 3 sp., A, B, and C. 

Macoma nasuta Conrad. 

* Macoma, 2 sp., A and B. 

Modiolus ( aff.) rectus Conrad. 

*Modiolus n. sp.? 

Nerera (aff.) pectinata Cpr. 

* N ucula n. sp. A. 

N ucula n. sp. A var. 

Ostrea (cf.) idriaensis Gabb. 

Panopea ( cf.) gene rosa Gould. 

Pecten peckhami Gabb. 

Pecten sanctrecruzensis n. sp. 

Phacoides acutilJneatus Conrad. 

Phacoides (Myrtea?) n. sp. 

Solemya ventricosa Conrad yo.?. 

Solen n. sp. ( aff. ) curt us Conrad. 

* Tellina ( cf.) arctata Conrad. 

* Tellina ( cf. ) oregonensis Conrad. 

Thracia ( aff.) trapezoides Conrad. 

Th yasira n. sp. " 

PELECYPODA-COntinued. 

Venus ( cf.) lenticularis Gab b. 

Y oidia impressa Conrad. 

GASTEROPODA. 

Actreon sp. A. 

Astyris n. sp. A. 

Bela clathrata Gabb. 

Crepidula prrerupta Conrad?. 

*Cylichna (aff.) petrosa Conr. or horni Gabb. 

* Dentalium near substriatum Conr. or coo peri 

Gab b. 

* Dentalium n. sp. A. 

Doli urn? n. sp. ?. 

Fusus ( cf.) mathewsonii Gab b. 

* Fusus ( cf. ) oregonensis Conrad. 

Fusus ( aff.) thracius Conrad. 

* Fusus, 3 n. sp., A, B, and C. 

Fusus or Perissolax sp. A. 

Galerus excentricus Gab b.?. 

Galerus ( aff.) mammillaris Brod. 

*Lunatia ( cf.) shumardiana Gab b. 

Natira sp. A. 

Neverita saxea Conrad. 

* Pleurotoma ( aff.) raricostata Gab b. 

Pleurotoma, 2 sp., A and B. 

Scala (Opalia) sp. A. · 

Sigaretus scopulosus Conrad. 

Solarium ( aff.) amoenum Conrad. 

*Solarium n. sp: A. 

CEPHALOPODA. 

Aturia ziczac Sowerby (?). 

MIOCENE. 

Three divisions are commonly recognized in the Miocene of California, the 

lower (Vaqueros), middle (Monterey), and upper (San Pablo). At certain localities 

the relations existing between these three divisions are very clear, while at others 

they are obscure, and at still others it appears as if the lower two are interbedded 

:with each other to a greater or less extent. In the vicinity of Mount Diablo, Doctor 

Merriam is able to differentiate a fourth division lying between the Monterey 

shale and the San Pablo, which he calls the Contra Costa County Miocene, and 

which is characterized, according to him, a by Olypeaster ( n brewe1·i~~us, Trocll.ita 

costeltata, several new species of Modiolus, etc. This last horizon has not as yet 

been recognized outside of the Mount Diablo Range. 

aMerriam, J. C., Bull. Dept. Geol. Univ. Cal., vol. 3, No. 16, 1904, p. 378. 

17260-No. 47-06----2 
18 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

VAQUEROS SANDSTONE. 

TYPE LOCALITY. 

The type locality is Lfs Vaqueros Valley, Monterey County, Cal. 

I NAME AND DESCRIPTION. 

This formation name was suggested by Mr. Homer Hamlin and .first used by 

~;~ ~~. ~.· Fairbanks in tjThe deseriptive text of the San Lu~s folio (California), 

DEFINITIQN. 

The Vaqueros sandsto e lies eonformably beneath the Monterey shale and 

rests conformably upon th . San Lorenzo formation and unconformably upon the 

Tejon (Eocene) or older fo mations. It varies in thickness in different localitieE!, 

its maximum being betwee;n 2,000 and 3,000 feet. 

I 

LOCALITIES. 

Martinez, Contra Costa County. 

Mount Diablo Range in Contra sta and Alameda counties. 

Santa Cruz Mountains, in San Mateo, Santa Clara, and Santa Cruz counties (Mindego Creek, Stevens 

Creek, Boulder Creek; ef

1

c. ) . 

Los Vaqueros Valley and Santa Lucia Range, Monterey County. · 

Lynchs Mountain, Corral de Pied' a Creek, Hazzard Canyon, Morro Creek, La Panza, and Toro. Creek 

San Luis Obispo County. 

Barker's ranch (Kern River), P?so Creek, San Emidio Canyon, 6 miles southeast of Annette, and 

Avenal Canyon, Kern County. 

San Miguel Island and Santa ez Mountains, Santa Barbara County. 

Ojai Valley, Sespe oil district, a:hd Santa Monica Mountains, Ventura County. 

Santa Monica Mountains, Eagle f ock Valley, and Pasadena, Los Angeles County. (This formation 

may also be younger thfn the Vaqueros. ) 

Santa Ana Mountains and El T<i>ro, Orange County. 

Carrizo Creek, San Diego Count (?). (Probably younger than the Vaqueros.) 

According to Merria , the lower Miocene or Agasoma zone occurs in 

Oregon, and the same ho izon is probably represented still farther north by a 

part of the Oligocene-Mio ene series of Washington. 

FAUNA. 

The Vaqueros has a v ry characteristic fauna, consisting of numerous forms 

peculiar to itself besides mr ny species found in the overlying formations. A few 

Vaqueros species are found in the transitional beds between it and the San 

Lorenzo (Oligocene), but /none of the members of its fauna, so far as known, 

reach into the Tejon (Eocrne). On account of the occurrence of species of the 

peculiar genus Agasoma i~ the lower Miocene, Doctor Merriam has given it the 

appropriate name "Agasoma zone." a He has tentatively divided this into ·two 

stages; the probably lowe}· of the two characterized by Tu'rritella lwffmanni and 

the upper by Turritella oc yana . . No differentiation of the two stages is attempted 

in this paper. , . 

Pecten fauna.-The ecten fauna of the Vaqueros sandstone or Agasoma 

zone is a large one and con ·ists of the following species: P. andersoni, P. andersoni 

a j ull. Dept. Geol. Univ. Cal., vol. 3, 1?04, p. 378. 
MIOCENE FORMATIONS. 19 

var. barkerianus, P. boVJersi, P. branneri, P. crassicardo and its variety hamilton1:, 

P. (Hinnites) giganteus, P. estrellanus, P. magnolia, P. 1niguelensi8, P. peckhami, . 

P. perrin·i, P. sespeensis and its variety hydei, P. sanctmcruzensis, and P. vaJtghani. 

The following species are of uncertain stratigraphic standing; some or all 

of them may extend into the lower Miocene: P. carrizoensis, P. cerro8ensis var. 

mendenhatli, P. deserti, P. fucanus, IY. hamlini, P. keepi, ..P. neahensis, P. nutteri, P. propatu,l1ts, and P. sta11;/ordensis. 

The following is the fauna (with the exception of Pecten) found in the 

Vaqueros sandstone of central California: 

List of Vaqueros sandstone ( lmver Miocene) fossils. 

[Those marked with an asterisk (*) are snppo:;;ed to be characteristic of this horizon.] 

ECHINOIDEA. 

Scutella fairbanksi Merriam. 

BRACHIOPODA. 

*Terebratella (?) n. sp., A. 

PELECYPODA. 

Angulus ( cf.) buttoni Dall. 

Area ( cf.) canalis Conrad. 

Area microdonta Conrad. 

(*?)Cardium (Trachycardium) n. sp., A. 

Chione succincta Valenciennes(?). 

·>'Chione mathewsonii Gabb. 

Chione n. sp., A (very large). 

·*Corbula ( cf.) evansiana Shumard. 

·:'Dosinia conradi Gabb. 

*Dosinia mathewsonii Gabb. 

Dosinia ( cf.) montana Conrad. 

Dosinia (aff.) ponderosa Gray. 

*Glycymeris n. sp. A (very large). 

Leda taphria Dall. 

*Leda sp.?. 

Macoma ( cf.) calcarea Gmelin. 

Macoma nasuta Conrad. 

Mactra californica Conrad (?). 

Mytilus mathewsonii Gabb. 

*Ostrea ( aff.) titan Conrad. 

Panopea generosa Gould?. 

Pecten (see previous list). 

* Periploma n. sp. A. 

Phacoides acutilineatus Conrad. 

Phacoides richthofeni Gabb. 

*Pinna alamedensis Yates. 

Psamrnobia edentula Gab b. 

Saxidomus gibbosus Gabb. 

Solen sicarius Gould. 

Tapes truncata Gabb. 

*Tellina n. sp. A ( aff.) bodegensis Hinds. 

Tellina sp. 

*TiYela ineziana Conrad. 

Venus pertenuis Gabb. 

*Yoldia n. sp. A (aff.) cooperi Gabb. 

GASTEROPODA. 

* Acmrea n. sp. A. _ 

* Actreon n. sp. A. 

*Agasoma barkerianum Cooper. 

* Agasoma ( cf.) gravida Gab b. 

* Agasoma kernianum Cooper. 

Astyris n. sp. (aff.) tuberosa Cpr. 

*Calliostoma n. sp. B. 

*Chlorostoma n. sp. A. 

*Conus n. sp. ,A.. 

Crepidula princeps Conrad. 

*Cuma biplicata Gabb. 

*Dentalium n. sp., B. 

*Fissuridea n. sp., A. 

*Fusus sp. A. 

Galerus ( aff.) excentricus Gab b. 

Galerus mammillaris Brod. (?) 

Megatebennus bimaculatus Dall. 

Nassa ( cf.) mendica Gould. 

*Natica ocoyana Conrad. 

Neverita callosa Gabb. 

*Ocinebra ( aff.) lurida Mid d. 

Olivella pedroana Conrad. 

*Pyrula (?) sp. 

Sigaretus scopulosns Conrad. 

*Solarium sp. 

*Tritonium sp. 

Trochita costellata Conrad (?) 

Trophon ponderosum Gabb. 

*Tnrritella hoffmanni Gabb. 

*Turritella ocoyana Conrad. 

*Tnrritella variata Conrad. 

CRUSTACEA. 

Balanus estrellanns Conrad. 

PISCES. 

*Galeocerdo productus Agassiz. 

*Lamna clavata: Agassiz. 

*Oxyrhina tumula Agassiz. 
.. 

20 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

MONTEREY SHALE. 

TYPE LOCALITY. 

The type locality is vicinity of Monterey, Monterey County, Cal. 

NAME AND DESCRIPTION. 

This formation was named and described by William P. Blake in Proceedings 

of the Academy of Natural Sciences of Philadelphia, vol. 7, 1855, pp. 328-331. 

DEFINITION. 

In describing the shale beds in the vicinity o-f Monterey Blake has the following to say reg·arding· the stratigraphic relations: ''This interesting formation, 

· teeming with the skeletons of microscopic organisms, appears to overlie and to 

be conformable with the Tertiary strata that underlie a part of the town of 

Monterey and e~tend to and beyond the mission of San Carlos. These strata 

rest upon a porphyritic granite, which fonns the projection of the coast called 

Point Pinos, and is the bulwark of the bay." The only fossils mentioned by 

Blake as occurring in the formation are: Tellina congesta Conrad, LutrrJria traski·i 

Conrad, and diatoms belonging to the genus Ooccinodiscus. 

The term "Monterey shale," as now accepted, applies to the very characteristic 

shale formation typically developed in the Santa Lucia and Santa Cruz ranges. 

It sometimes attains a thickness of over 2, 000 feet, and · at some localitiel:l is 

interbedded with layers of sandstone or thin strata of a rather impure limestone. 

The formation is underlain con-formably by the Vaqueros sandstone at most localities, but at a few it rests directly upon older rocks. In some places the line of 

demarcation between the · V aqueroB and Monterey is very distinct; while at others 

the beds seem to, merge into each other through a series of alternating sand and 

shale layers. As suggested by Doctor Lawson, the shale probably has an inshore 

equivalent of sandstone, whose fauna is doubtless entirely different from that of 

the shale and probably shows a marked resemblance to that of the underlying 

Vaqueros and overlying Contra Costa County Miocene. Following the deposition 

of the Monterey came the great upheaval along the coast which resulted in the 

elevation of the shales and their subsequent erosion. As a' result of this a line 

of marked unconformity generally separates the ·Monterey from the overlying 

formations. 

LOCALITIES. 

Southeast of Pinole, Contra Costa County. 

· Langley Hill and Alpine district, San Mateo County. 

Castle Rock Ridge, .Santa Clara County. 

Castle Rock Ridge, vicinity of Ben Lomond, Felton, Gibbs, and Santa Cruz, Santa Cruz County. 

Monterey, Carmelo Valley, and Santa Lucia Range, Monterey County. 

Big Panoche Creek to Kreyenhagens, Fresno County. 

Templeton, Atascadero, Lopez Canyon, Point Buchon to near mouth of Davis Canyon, northeast of 

· Arroyo Grande, and other localities in San Luis Obispo County. 

Northwest of Tulare Lake, Tulare County. 
MIOCENE FORMATIONS. 

McKittrick district, Kern County. 

Ojai ranch and vicinity, Ventura County. 

Santa Inez Mountains, Santa Barbara County. 

San Pedro, Santa Monica Mountains, anu east of Los Angeles, Los Angeles County. 

FAUNA. 

21 

The fauna of the J\Ionterey shale is quite limited, and the fossils are generally 

preserved only in the form of casts or molds. Pecten p eclchami is one of the 

most abundant fossils, but as it is not confined to the Monterey its value as an 

agent of correlation is only nominal. The most characteristic species appear to be 

Area montereyana and ·a large, coarse-sculptured Leda. 

P ecten fauna.-The Pecten fauna of the Monterey (including such species as 

are found both below and above it, or in its included sandstones~ but which, on 

account of habitat, are not found in the typical shale) is as follows: P. andersoni, 

P. crassicardo, P. e8trellanus, P. fi£innites) giganteus, .P. pedroanus, and P. 

)Jeclcha1ni. 

The following species have a more or less uncertain stratigraphic status, and 

some or all of them may extend into or through the Monterey or its equivalents: 

P. bowersi, P. carrizoensis, P. cen·osensis var. mendenhalli, P. discus, P .. fucanu8, 

P. keepi, P. lompicoensis, P. neahensis, P. nutteri, P. perrini, P. propatulus, and 

P. stanfordensis. 

The following species have been found in the Monterey shale near the type 

locality or in the Santa Cruz Mountains, just to the north and across Monterey 

Bay from it. 

L ist of J.Vfonterey shale (middle 1.lfiocene ) joss·ils. 

[Those marked with an asterisk (*) a re supposed to be characteristic.] 

PELECYPOD A. 

*Area montereyana Osmont. 

Callista angustifrons Conrad. 

Chione mathewsonii Gabb. 

* Corbula sp., probably new. 

Cytherea sp. A. 

* Diplodonta n. sp. (aff.) serricata Reeve. 

* Glycymeris (?) n. sp. 

* Leda n. sp. A. 

* Leda n. sp. B. 

* Lutraria traskii Conrad. 

PELECYPODA-COntinued. 

Pecten andersoni n . sp. 

Pecten peckhami Gabb. 

* Phacoides like crenulata. 

Saxidomus sp. 

* Semele n. sp. A. 

Siliqua sp. 

*Tellina co'ngesta Conrad. 

GASTEROPODA. 

Cy lichna ( cf. ) petrosa Conrad. 

The fauna of the Carrizo Creek beds, which are undoubtedly Miocene but of 

uncertain horizon, belongs to an entirely separate biologic province from that of 

the principal California Miocene, and for that reason has few species in common 

with any of the other known California deposits. The following is a list of the 

fossils so far recognized from the Carrizo Creek beds. (See also list of fossils 

from Santa Rosalia, Lower California, under Pecten cerrosensis Vltl'. mendenhalli, 

p. 85.) 
22 TERTIARY AND QU.ATERN ARY PECTENS OF CALIFORNIA. 

List of fossils from the Carrizo Creek beds (Miocene). 

ANTHOZOA. 

Diploria bowersi Vaughan (Mss. ). 

Favia merriami Vaughan. 

Plesiastrea californica Vaughan ( Mss. ) . 

Siderastrea californica Vaughan (Mss. ). 

Stephanocoenia fairbanksi Vaughan. 

PELECYPODA-COntinued. 

Ostrea vespertina Conrad. 

Pecten carrizoensis n. sp. 

Pecten cerrosensis var. mendenhalli n. var. 

Pecten deserti Conrad. 

Stephanocoenia fairbanksi var. columnaris 

Pecten (Hinnites) giganteus Gray. 

Pecten keepi n. sp. 

Vaughan. 

ECHINOIDEA. 

Clypeaster bowersi Merriam. 

PELECYPODA. 

Anomia subcostata Conrad. 

Area n. sp. (?) A. 

Phacoides ( cf. ) acutilineatus Conrad. 

Pholas (aff.) crucigera Sowerby. 

GASTEROPODA. 

Cyprrea sp. indet., large and probably new. 

Malea ( + Dolium) near ringens Sower by. 

Oliva (?) sp. indet. 

Cardium (Trachycardium) n. sp. (aff.) quadrige- Pol~ices (Neverita) recluziana Deshayes. 

Strombus n. sp. (aff.) granulatus Sowerby. 

Strombus (?) n. sp. B. 

narium Conrad. 

Dosinia sp., perhaps new. 

Gastrochrena sp. 

Lithophaga sp. 

Tivela ( cf.) ineziana Conrad. 

Turritella ( cf.) hoffmanni Gab b. 

SAN PABLO FORMATION. 

TYPE LOCALITY. 

The type locality is south side of San Pablo Bay, near Union oil refinery, 

Contra Costa County, Cal. 

NAME AND DESCRIPTION. 

The formation was named and described by Dr. J. C. Merriam, in Bulletin 

of the Department of Geology, University of California, vol. 2, No. 4, 1898, p. 

113 et seq. 

DEFINITION. 

The formation at the type locality consists of a series of sandstones, tuffs, 

and ashes with an approximate total thickness of between 1,500 and 2,000 feet. 

At this locality it rests apparently conformably upon the Contra Costa County 

Miocene. In the S~linas Valley, and at many other places, formations which 

are probably the equivalents of the San Pablo rest unconformably upon the 

Monterey shale. In the Santa Cruz quadrangle, beds containing the supposedly 

characteristic San Pablo echinoderm, Astrodapsis tttmi(ius Remond; rest unconformably. upon the Monterey, and are overlain conformably by at least a part 

of the Purisima (lower Pliocene). 

LOCALITIES. 

San Pablo Bay, WalnQ.t Creek, and Kirkers Pass; Contra Costa County. 

Scott Valley, Santa Cruz County. 

San Ardo and othe.r: localities in the Salinas and adjacent valleys, Monterey County. 

Coali11ga and vicinity, Fresno County. 

Estrella Valley; Santa Margarita and vicinity, 3 miles east of La Panza, Cammatta ranch, Music P. 0., 

and Pismo and vicinity, San Luis Obispo County. 

_Santa Catalina Island, Los Angeles County. 
MIOCENE FORMATIONS. 23 

FAUNA. 

Doctor Merriam, in his original definition of the San Pablo formation, says: a 

""The series of strata characterized by the presence of Astrodapsis and Rcutella 

( Olypeaster) gabbi may, with reference to its more important features, be treated 

as a distinct formation, and will be referred to in this paper as the San Pablo 

formation." By definition, therefore, the formation is limited in a genAral way 

to the zones of the above-mentioned echinoderms. In most of the localities where 

the formation has been recognized, at least one of these forms has generally 

been detected. Ostrect titan, Ta1niosoma gregarict, Pseudocardi~l1TI gctbbi, Chorus 

belcheri, a small Ocinebra, and sever~J species of· P ecten are also commonly found 

in its fauna. 

According to 1'Ierriam the fauna of the San Pablo is known so far by about 

fifty species, of which nearly one-third are peculiar to this formation, about onefourth are known also from the Contra Costa County Miocene, and OI?-e-sixth from 

the Merced; while of the total number a little less than one-half are extinct. The 

writer has noted several San Pablo species extending down into the Vaqueros (lower 

Miocene); while his estimate of the extinct species is about 65 per cent, rather than 

a little less than 50 per cent as given by Merriam. 

Pecten fauna.--The Pecten fauna of the San Pablo, and its supposed equivalents 

in age, consists of the following species: Pecten cindersoni, P. coosensis, P. crassicardo 

and its variety hamiltoni, P. discus, P. eldridgei, P. estrellanus and vars. catalince 

and ermin~ts, P. (Hinnites) giganteus, P. hastatus var. hericius, P. nutteri, P. moeni, 

P. pabloensis, P. pedroantts. 

The following f<pecies of more or less uncertain status may occur in the San 

Pablo or its equivalents: }.J. carrizoensis, P. cerrosensis var. mendenlwlli, P. dilleri, 

P . .fucanus, P. keepi, P. nealiensis, P. propatulus. 

The following fossils have been found in the San Pablo formation at San Pablo 

Bay, Kirker Pass, and other localities in the Mount Diablo region. 

List of San Pablo formation (upper .1tfiocene) fossils. b 

[Those marked with an asterisk(*) have been found by the writer at the type locality; those followed by (C) are supposed 

to be characteristic, and those followed by (L) also occur in the recent fauna of the coast.] 

ECHINOIDEA. 

* Asterias remondi Gabb (C). 

* Astroda psis tumid us Remond (C) . 

*Astrodapsis whitneyi Remond (C). 

Astrodapsis n. sp. Merriam (C). 

Scutella (Clypeaster) gabbi Remond (C),. 

PELECYPODA. 

*Cardium ( cf.) quadrigenarium Conrad ( L). 

Cyrena californica Gabb. , 

Dosinia ponderosa Gray (L). 

Gari alata Gabb (C). 

*Glycymeris ( +Axinea) sp. 

aMerriam, J. C., 1898, p. 113. 

PELECYPODA-COntinued. 

Macoma nasuta Conrad (L). 

*Mactra ca1ifornica Conrad (?) (L). 

Mactra falcata Gould (L). 

Modiolus sp. (C ?). 

*Mulinia densata Gabb (C). 

Mytilus sp. (C ?). 

Ostrea bourgeosii Gabb (C)~ 

Ostrea titan Conrad (C). 

*Pecten andersoni n. sp. 

*Pecten pabloensis Conrad (C). 

*Pecten crassicardo Conrad. 

Pinna alamedensis Yates. 

bTurner, H. W., .Jour. Geol., vol. 6, pp. 483 et seq., from which a part of this list is copied. 

• 
• 

24 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

List of San Pablo formation (upper Miocene) fossils-Continued. 

PELECYPODA-COntinued. 

Pseudocardium gabbi Remond. 

*Saxidomus gracilis Gould (L). 

Solen sp. 

Tapes staminea Conrad (L). 

Tapes staleyi Gabb (?). 

*Tresus nuttalli Conrad (L). 

* Zirphrea sp. ( C ?) 

GASTEROPODA. 

* Acmrea sp.. (C). 

Bittium asperum Gabb (L). 

Calliostoma n. sp. (?) Merriam (C ?) . 

·*Chlorostoma (?) sp. (C ?). 

Crepidula adunca Sowerby (L). 

Crepidula princeps Conrad? (L). 

GASTEROPODA-COntinued. 

Fusus (?) sp. (C ?). 

Li torina rem.ondi Gab b (C). 

Litorina planaxis Phil. (L). 

Lunatia lewisii Gould (L). 

*Ocinebra (aff.) cancellina Philippi (C). 

Ocinebra lurida Middendorf (?) (L). 

*Olivella pedroana Conrad (L). 

*Opalia sp. (C ?). 

Purpura canaliculata Duclos ( L). 

Purpura saxicola Valenciennes ( L). 

Ran ella californica Hinds ( L). . 

*Tritonium (Priene ?) sp. (C ?). 

*Trochita filosa Gabb. 

Trochita n. sp. Merriam (C). 

Trophon ponderosum Gabb. 

In addition to the above the following species have been found in the Santa 

Margarita formation (probable equivalent of the San Pablo) in the Salinas Valley, 

Monterey County, and southward: 

List of Santa Margarita format'ion ( = San Pablo) fossils from Salinas Va,Uey and southward. 

ECHINOIDEA. 

Astrodapsis tumidus Remond. 

Uidario spines and fragments of tests. 

PELECYPOD A. 

Area canalis Conrad. 

Area ( cf.) microdon ta Conrad. 

Cardium (cf.) meekianum Gabb. 

Cardium ( cf.) quadrigenariurn Conrad. 

Chione n. sp. (large; coarse sculpture). 

Chione sp. (medium sized). 

Glycymeris ( cf.) patulus Conrad. 

Lima sp. 

Mactra ( cf.) californica Conrad. 

Mactra ( cf.) falcata Gould. 

Mytilus sp. (very large). 

Ostrea attwoodi Gabb. 

Ostrea bourgeoisii Remond. 

Ostrea titan Conrad. 

Pecten crassicardo Conrad. 

Pecten discus Conrad. 

Pecten eldridgei n. sp. 

Pecten estrellanus Conrad. 

Pecten estrellanus var. terminus n. var. 

PELECYPODA-eontinued. 

Pecten hastatus Sby. var. hericius Gould. 

Pecten oweni n. sp. 

Phacoides acutilineatus Conrad. 

Pseudocardium ( cf.) gabbi Remond. 

Saxidomus ( cf.) gibbosus Gab b. 

Solen sicarius Gould. 

Tresus sp. 

Venus pertenuis Gabb. 

GASTEROPODA. 

Astyris sp. 

Chorus belcheri Hinds. 

Fusus ( aff.) robustus Trask. 

Nassa sp. 

Natica or Neverita sp. 

Ocinebra (aff.) cancellina Philippi. 

Olivella ( cf.) pedroana Conrad. 

Pisania n. sp. ( aff.) fortis Carpenter. 

Trochita filosa Gabb. 

Turritella sp. 

CRUSTACEA. 

Balanus estrellanus Conrad. 

Tamiosoma gregaria Conrad. 
TERTIARY FORMATIONS. 25 

PLIOCENE. 

Two more or less distinct faunal zones are recognizable in the Pliocene; 

the lower characterized by many forms identical to or closely related to those of 

the Miocene; while the upper appears to lack these older species and contains 

but comparatively few forms which are not found living at the present time. 

The fauna of the Purisima formation is characteristic of the lower horizon, 

while that of the Merced represents the upper. 

P URISLMA FOR L}IA TION. 

TYPE LOCALITY. 

The type locality Is m the vicinity of the mouth of Purisima Creek, San 

Mateo County, Cal. 

NAME AND DESCRIPTION. 

This formation was named and described by H. L. Haehl and Ralph Arnold 

m Proceedings of the American Philosophical Society, vol. 43, No. 175, 1904, pp. 

22-24. 

DEFINITION. 

The Purisima formation consists of a series of conglomerates, fine sandstones, 

and sandy shales, with a total thickness of about 800 feet, and is typically 

developed jn the vicinity of the lower portion of Purisima Creek, San :Mateo 

County. The formation also covers a considerable territory in other parts of 

the Santa Cruz quadrangle, especially that portion of the area adjacent to the 

coast and north of Pescadero Creek. Beds of age probably equivalent to at least 

a part of the Purisima are known from the Cholame Valley, Monterey County, 

and elsewhere south of the type locality. At least a portion of the beds on Eel 

River, Humboldt County, are doubtless the equivalent of the Purisima. As 

pointed out by Ashley, a the Purisima formation (his "Transition beds") and its 

probable equivalents appear in their lower portions to be more or less transitional 

toward the Miocene. 

Much uncertainty exists in the mind of the writer as to the exact relation 

existing between the Purisima and San Pablo formations. After a careful examination of a large amount of material from the type localities of the two formations 

and also from supposedly equivalent formations in the Salinas Valley and adjacent 

regions, supplemented by field studies at most of the localities from which the 

material was obtained, it appears evident that the two formations are quite 

intimately related. tT ust exactly what the nature of this relation is, however, bas 

not yet been determined. t is a complex problem, and is one which will require 

much careful field and labo ,atory study for its solution. The Purisima fauna, taken 

as a whole, appears to be younger than the aggregate San Pablo fauna, and for 

the sake of convenience ill be tentatively considered as the later of the two. 

a Ashley, G. H., Proc. California Acad. Sci., ser. 2, vol. 5, 1895, p. 330. 
26 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

The greater part of the San Pablo should, without question, be placed in the 

Miocene, while the major portion of the Purisima is undoubtedly Pliocene. In 

accordance with these facts each formation has been arbitrarily placed in that epoch 

with which it appears to be the more closely allied. 

Crescent Cit ~ Del Norte County. 

Eel River, Humboldt County. 

Tomales Bay, Marin County. 

LOCALITIES. 

Halfmoon Bay to Pescadero Creek, vicinity of La Honda, Alpine district, and ridge west of Portola 

Valley, San Mateo County. 

Near mouth of Stevens Creek, Santa Clara County. 

West branch of Soquel Creek. and Scott Valley, Santa Cruz County. 

Cholame Valley, Lewis Creek, and Priest Valley, Monterey County. 

Vicinity of Coalinga, Kreyenhagens, and the Kettleman Hills, Fresno County. 

Casmalia, Santa Barbara County. 

Temescal Canyon in Santa Monica Mountains, Third street and Broadway tunnels in Los Angeles, and 

San Fernando tunnel, Los Angeles County. 

Olinda, Orange County. 

Cerros Island, off the coast of Lower California, Mexico. 

The formations exposed at the following localities probably represent the upper 

part of the Purisima and the lower part of the Merced, and correspond to Dall's San 

Diego formation: 

Santa Barbara and Rincon asphalt mine, Santa Barbara County; Piru Creek and Eureka Canyon, 

Ventura County; Santa Monica Canyon and San Pedro, Los Angeles County; San Juan 

Capistrano, Orange County; San Diego and Pacific Beach, San Diego County. 

FAUNA. 

The fauna of the Purisima in central California contains a few species which 

extend into the Vaqueros (lower Miocene), many more which are common to it and 

to the San Pablo (upper Miocene), and a large number which are found in the 

Merced above it or are living at the present time. A number of the species common to the San Pablo and the Purisima are not found in the Merced or later, while 

a large number of the species found in both the Merced and the Purisima do not 

extend into the San Pablo, so far as known. Quite a number of the forms found in 

the Purisima are peculiar to this formation. Of the total Purisima fauna, about 30 

per cent are believed to be extinc:t. 

The fauna of the· '' Wildcat" series of Humboldt County, as determi~ed by 

Merriam and given by Lawson, a indicates the probable contemporaneity of at least a 

part of this series with the Purisima. The lower part of the San Diego formation 

probably represents the middle and upper portions of the Purisima. 

Pecten fauna.-The Pecten fauna of the Purisima and supposed equivalent formations is as follows: P. ashleyi, P. a·uburyi, P. bartscl"i, P . . bellus, P. bellilamellatus, P. caurinu8, P. cerrosensis, P. coalingaensis, P. cooper·i, P. diller'i, P. estrellanus 

var. catalinm, P. (Hinnites) giganteus, P. hastatus and its varieties hericius; hindsii, 

navarchus, strateg·us, I->. healeyi, ].J. lwmphilli, P. islandicus, P. jordani, P. latiaua Lawson, A. C., Bull. Dept. Geol., Univ. Cal., vol. i, 1894, No.8, pp. 260-261. 
. . . . . . 

~ . . . . 

:·· . .. . ... .. . . . . .. . . .. . . . • •. ! : : o• •. : • ...... . . . . . . .. . . . . . . . . .. . . 

.. . ... . . .. . . . . . :. :·. : 

PLIOCENE FORMATIONS. 27 

ritus, P. lawsoni, P. lecon ei, P. me1'riami, P. nutteri, P. opuntia, .J>. oweni, P. 

parmeleei, P. pedroanus, . purisimaensis, P. riversi, P. stearnsii, P. turneri, 

P. veatcl~.Jii, P. woohburnei, P. wattsi, and P. 1JJattsi var. morani. 

The following species ave been found in the Purisima formation at different 

localities in the Santa Cruz uadrangle: 

uri8ima formation (lower Pliocene) fossils. 

[Those species marked with an asterisk (*) are supposed to be characteristic; those followed by (M) are also found in the 

Miocene; thos by (N) in the Merced, and those by (l) are still living.] 

ECHINOIDEA. 

Astrodapsis n. sp. Merriam. 

Scutella interlineata Stimpson. 

BRACHIOPODA. 

Glottidia albida Hinds. 

PELECYPOD A. 

Area canalis Conrad (M). 

Area trilineata Conrad (1Vl). 

Callista angustifrons Conrad ( M) ( l ? ) . 

Cardium meekianum Gabb (M ?) 

*Cardium meekianum Gabb n. v r. A. 

Chione gnidia Broderip and Sowe' by (l). 

Chione sp. 

Clidiophora punctata Conrad ( l) . 

Corbula sp. 

Cryptomya californica Conrad (l) 

* Cryptomya n. sp. A. (aff. califo nica Conrad). 

Dosinia ponderosa Gray ( l). 

Dosinia sp. 

* Loovicardium n. sp. ( aff. substri tum Conrad). 

Leda ( cf.) fossa Baird (l ?) . 

Leda taphriaDall (l). 

Macoma calcarea Gmelin (l). 

Macoma inquinata Deshayes (l). 

Macoma nasuta Conrad (1). 

1Vlactra californica Conrad ( l). 

Mactra hemphilli Dall (l). 

Modiolus rectus Conrad ( l). 

Moerella salmonea Carpenter (l). 

1Vlytilus mathewsonii Gabb (M). 

N ucula castrensis Hinds ( l) . 

Panomya ampla Dall (l). 

Panopea generosa Gould (Z). 

*Pecten hastatus Sowerby(smoot var.). 

* Pecten healeyi n. sp. 

Pecten nutteri n. sp. 

Pecten oweni n. sp. 

*Pecten purisimaensis n. sp. 

Phacoides acutilineatus Conrad ( ). 

Phacoides nuttalli Conrad ( l). 

Saxidomus gibbosus Gabb (M). 

PELECYPOD A-COntinued. 

Siliqua lucida Conrad ( l). 

tiiliqua patula Dixon (l). 

Spisula catilliformis Conrad (l). 

Spisula falcata Gould (l). 

Solen sicarius Gould. 

Tapes staleyi Gabb (N) (M?). 

Tapes tenerrima Carpenter (l). 

Tellina ( cf. ) congesta Conrad ( M) . 

* Tellina n. sp., A. 

Tresus nuttalii Conrad (M). 

Venus pertenuis Gabb (M). 

Yoldia cooperi Gabb (l). 

Y oidia scissurata Dall ( l). 

Zirphooa gabbi Tryon (l). 

GASTEROPODA. 

Admete grarilior Carpenter (N). 

Astyris californiana Gaskoin (l). 

Astyris gausapata Gould (l). 

Astyris r{chthofeni Gabb (N). 

Bittium asperum Gabb (l). 

Boreotrophon pacificus Dall ( l). 

*Buccinum n. sp. A. 

*Calliostoma n. sp. A. 

Chrysodomus liratus Martyn (l). 

Chrysodomus tabulatus Baird ( l). 

*Chrysodomus n. sp. A. 

Crepidula princeps Conrad (M) (N). 

Crepidula havicelloides Nuttall (l). 

Crepidula ( cf.) onyx Sower by ( l). 

Crepidula rugosa Nuttall. 

*Dolichotoma n. sp. (aff. carpenteriana Gabb ). 

Drillia incisa Carpenter (l). 

*Fusus n. t"p~ (aff. rugosus Trask). 

*Galerus inornatus Gabb. 

Leptothyra paucicostata Dall (l). 

Lunatia lewisii Gould ( l). 

N assa californiana Conrad ( N) . 

N assa mendica Gould ( l). 

N assa perpinguis Hinds ( l). 

Natica clausa Broderip and Sowerby (l). 

*Neptunea humerosa Gabb. 
. . .. . . . .. . .. . ........ . . .. . . . . . . . . . . ··: . . . . 

. . . . : .... · .... :: .... : · .. : .. : · .. : . :: ... · ... · .. .... . · .. · . . .. . . ...... . · .. · ·.: :·. ·.: .... :: . : .·::··.::~.:: .. : 

·. : .. : ·. : :·: : : .. : •• . • . 

• • 

.. • . o• . . . 

• • .. .• . . .. . . . . . . 

28 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

· List of Purisima formation (lower Pliocene) fossils-Continued. 

GASTEROPODA-COntinued. 

Neverita recluziana Petit (l). 

Olivella intorta Carpenter (l). 

Pleurotoma perversa Gabb (l). 

Pleurotoma sp. 

Priene oregonensis Redfield (l). 

Purpura crispata Chemnitz (l). 

Rostellaria indurata Conrad ( M). 

Serpulorbis squamigerus Carpenter (l). 

GASTEROPODA- COntinued. 

Sigaretus de bilis Gould ( l). 

Solariella peramabilis Carpenter (l). 

To rna tina culcitella Gould (l). 

Tritonium sp. 

*Voluta n. sp. (?) A. 

CRUSTACEA. 

Balanus estrellanus Conrad (M). 

The San Diego formation in a genera] wa3r is the representative of the 

Purisima in southern California, although the former, at least the fossiliferous 

horizon, may not extend as far back in the. time scale as the base of the latter. 

The fauna of the San Diego formation as developed in the type section at Pacific 

Beach, north of San Diego, San Dieg~ County, is as follows: 

List of San Diego formation fossils. 

[Those marked with an asterisk (*) are supposed to be extinct.] 

ECHINOIDEA. 

Echinarachnius excentricus Eschscholtz. 

Strongylocentrotus purpuratus Stimpson. 

BRACHIOPODA. 

Laqueus jeffreysi Dall. 

PELECYPODA. 

Leda taphria Dall. 

Macoma nasuta Conrad. 

Mactra (Spisula) catilliformis Conrad. 

Metis alta Conrad. 

Modiolus rectus Conrad. 

Ostrea veatchii Gabb. 

Pecten ashleyi n. sp. 

Pecten bellilamellatus n. sp. 

Pecten cerrosensis Gabb. 

Pecten cooperi u. sp. 

Pecten hastatus Sowerby. 

Pecten hastatus var. hericius Gould. 

PELECYPODA-COntinued.' 

Peden hastatus var. navarchus Dall. 

Pecten healeyi n. sp. 

Pecten hemphilli Dall. 

Pecten opuntia Dall. 

Pecten stearnsii Dall. 

Phacoides acutilineatus Conrad. 

Phacoides nuttalli Conrad ( =Lucina id. ). 

Pododesmus macroschisma Deshayes. 

Tapes staminea Conrad. 

G.ASTEROPODA. 

Crepidula princeps Conrad. 

Dentalium neohexagonum Sharp and Pilsbry. 

Neverita recluziana Petit. 

Opalia anomala Stearns. 

Opalia varicostata Stearns. 

Purpura crispata Chemnitz. 

Scala stearnsii Dall. • 

Scala tincta Carpenter. 

· Turritella cooperi Carpenter. 

MERCED FORMATION. 

TYPE LOCALITY. 

The type locality is the sea cliff south of. Lake Merced, San Mateo County, Cal. 

N .AME AND DESCRIPTION. 

This formation was named and described by A. C. Lawson, in Bulletin of 

the Department of Geology, University of California, vol. 1~ No. 4, 1893, pp. 142 

· et seq. 

. I 
PLIOCENE FORMATIONS. 29 

DEFINITION. 

The type section of thl Merced formation consists of a series of rather soft, 

gray. sandstones and sandy shales, interbedded with hard pebbly conglomerates, 

hard well-cemented shell la ers, and occasional lignitic seams. The total thickness of the formation is a~proximately 5,000 feet. In age the Merced probably 

represents the upper Pliocene and lower Pleistocene, although there is no apparent unconformity in the ty e section, which is certainly Pliocene at the base and 

Pleistocene at the top. . 

. LOCALITIES. 

,'tfytilus beds, Shoalwater Bay, 0 eg. (Dall, 1898, p. 336). 

Upper portion of the "Wildcat ormation," Eel River, Humboldt County (?). 

Sea cliffs south of Lake Merce and foothills between them and Twelvemile Creek; north of 

Pillar Point; uppermost beds in sea cliff at mouth of Aiio Nuevo Creek, San Mateo 

County. 

Felt Lake, near Stanford Univer ity, Santa Clara County. 

Uppermost beds at Capitola, San a Cruz County. 

Beds at Bath House Beach and at least a portion' of Packards Hill beds, Santa Barbara, Santa 

Barbara County. 

Old irrigating ditch north of V e 'tura, Ventura County. 

Pliocene and lower portion of San Pedro formation, Deadman Island and San Pedro; Santa 

Monica Canyon, Los An eles County. 

San Juan Capistrano, Orange Co nty. 

Upper portion of San Diego for ation, Pacific Beach, and San Diego, San Diego County. 

FAUNA. 

The fauna of the lowe beds in the Merced formation indicates clearly their 

Pliocene age, while at the top the fossils show the Pleistocene origin of this 

part of the formation. I~ using ~'Merced" in its broader sense as a horizon 

name in the California col~mn it is deemed advisable to confine it, in a general 

way, to that period of th, standard geologic scale (viz, the Pliocene) to which 

the great bulk of the sfdiments of the formation belong. In correlating, 

however, the equivalence o~ the lower portion of the next higher formation (the 

San Pedro) to the upper p~rtion of the l\t1erced should be borne in mind. 

Pecten fauna.-No Pe tens have so far been recorded from the type section 

of the Nlerced, although b ds of probable equivalent age to the Pliocene portion 

of it have yielded the follo~ng species: P. ashleyi, P. belltts, P. bellilamellatus, 

P. ccrurintt8, P. cerrosensis, r .· cooperi, P. (I£innites) giganteus, P. hastatus and its 

varietie. s l~ericius, hindsii, [avar·chus, and stcrategus, P. healeyi, P. hmnphilli, P. 

islandicus, P. jordani, P. latiatrrittls, 1). opuntia, P. parmeleei, P. riversi, and 

P. stearnsii. 

The following fauna h s been found at or in the immediate vicinity of the 

type locality of the Merce 1 formation, and may be taken as characteristic of the 

horizon represented by the whole formation: 
30 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

List of Merced formation (upper Pliocene) fossils. a 

[Those unmarked have been reported from the type locality; those followed by (T) have been found only at Twelvemile 

Creek or Twelvemile House; those with (F) between Mussel Roek and Twelvemile House, and those with (S) at F(llt 

Lake, near Stanford University. Those species marked with an asterisk (*) are supposed to be extinct.] 

ECHINOIDEA. 

Echinarachnius excentricus Eschscholtz. 

* Scutella interlineata Stimpson. 

PELECYPODA. 

*Area trilineata Conrad. 

Cardium corbis Martyn. 

*Cardium meekianum Gab b. 

Cardium quadrigenarium Conrad (F). 

Chione succincta Valenciennes. 

Cryptomya californica Conrad. 

Macoma calcarea Gmelin. 

Macoma inquinata Deshayes (T). 

Macoma nasuta Conrad. 

Macoma (like sabulosa Spngl. ). 

Mactra californica Co'nrad. 

Modiolus rectus Conrad (T). 

Mytiius californianus Conrad. 

Mytilus edulis Linne. 

Ostrea sp. ? 

Pecten latiauritus Conrad (S). 

Pododesmus macroschisma Deshayes. 

Psephis lordi Baird. 

* Saxidomus gibbosus Gabb. 

Saxidomus gracilis Gould. 

Siliqua patula Dixon. 

Solen sicarius Gould. 

Spisula falcata Gould. 

* Tapes staleyi Gab b. 

Tapes staminea Conrad. 

PELECYPODA-COntinued~ 

Tresus nuttalli Conrad. 

V enericardia ventricosa Gould. 

GASTEROPODA. 

Astyris gausapata Gould. 

* Astyris richthofeni Gab b. 

Bittium asperum Gabb. 

Bittium filosum Gould. 

Chrysodomus liratus Martyn. 

Chrysodomus tabulatus Baird. 

Crepidula princeps Conrad. 

Crepidula navicelloides Nuttall. 

Drillia incisa Carpenter. 

Drillia inermis Hinds. 

Litorina planaxis Philippi (S). 

Lunatia lewisii Gould. 

Monoceros engonatum Conrad. 

Margarita pupilla Gould (S). 

Nassa fossata Gould. 

Nassa mendica Gould. 

Natica clausa Broderip and Sowerby. 

Olivella biplicata Sowerby. 

Olivella intorta Carpenter. 

Pleurotoma sp. indet. (F) . 

Purpura canaliculata Dud. 

Purpura saxicola Valenciennes. 

*Trochita filosa Gabb. 

Turritella sp. 

In southern California the Merced is represented by a somewhat different £auna 

£rom that found at the t.vpe locality. The Pliocene o£ Deadman Island, Los Angeles 

County, though representing a horizon probably a little lower than the bulk o£ the 

Merced, has a £auna which may be taken as approximately representing the Merced 

horizon in the southern part o£ the State. This Deadman Island £auna is as follows: 

List of Pliocene fossils from Deadman Island. 

[Those marked with an asterisk (*)are believed to be extinct.] 

ANTHOZOA. 

Caryophyllia californica Vaughan. 

• BRACHIOPODA. 

Laqueus jeffreysi Dall. 

*Terebratalia smithi Arnold. 

PEL:ECYPODA. 

Chama pellucida Sowerby. 

Corbula luteola Carpenter . 

Cumingia californica Conrad. 

Kellia laperousii Deshayes. 

Leda taphria Dall. 

a Lawson, A. C., 1893, pp. 144-145; 1895, p. 460; also Ashley, G. H., 1895, pp. 332-333. 
LEISTOC.ENE FORMATIONS. 

List of Pliofene fossils jro~n Deadman Island-Continued. 

PELECYPODA-COntinu d. GASTEROPODA-eontinued. 

Lyonsia californica Conrad. 

l\facoma calcarea Gmelin. 

Macoma inquinata Deshayes. 

Marcia subdiaphana Carpenter ( C ementia id.) 

Mytilimeria nuttalli Conrad. 

N ucula castrensis Hinds. 

Panomya ampla Dall. 

Panopea generosa Gould. 

Pecten caurinus Gould. 

Pecten hastatus Sower by. 

Pecten hastatus var. herieius Goul 

Pecten hastatus var. hindsii Carpe ter. 

*Pecten jordani Arnold. 

*Pecten stearnsii Dall. 

Phacoides acutilineatus Conrad. 

Phacoides californicus Conrad. 

Pholadidea penita Conrad. 

Protocardia centifilosa Carpenter. 

Solen sicarius Gould. 

*Thracia trapezoides Conrad. 

Thyasira gouldii Philippi. 

Thyasira bisecta Conrad. 

V enericardia barbarensis Stearns. 

V enericardia ventricosa Gould. 

Venus (Chione) simillima Sowerb 

GASTEROPODA. 

Acmrea insessa Hinds. 

Amphissa corrugata Reeve. 

Bela fidicula Gould. · 

Bittium asperum Gabb. 

Calliostoma canaliculatum Marty 

Calliostoma tricolor Gabb. 

Cerithidea californica Haldemann 

Chlorostoma brunneum Philippi. 

Chlorostoma montereyi Kiener. 

Chrysodomus sp. indet. 

Chrysodomus rectirostris Carpent r. 

Chrysodomus tabulatus Baird. 

Clathurella conradiana Gabb. 

Columbella gausapata Gould. 

Conus californicus Hinds. 

Cryptochiton stelleri Middendorf. 

* Drillia merriami Arnold. 

Drillia torosa Carpenter. 

Fusus barbarensis Trask. 

Hipponyx antiquatus Linne. 

Litorina planaxis (Nuttall) Philippi. 

Mangi-lia sculpturata Dall. 

Nassa californiana Conrad. 

Nassa fossata Gould. 

N assa mendica Gould. 

Nassa mendica var. cooperi Forbes. 

N assa perpinguis Hinds. 

Natica clausa Broderip and Sowerby. 

Neverita recluziana Petit. 

Ocinebra interfossa Carpenter. 

Olivella biplicata Sowerby. 

Olivella intorta Carpenter. 

Olivella pedroana Conrad. 

* Pleurotoma bartschi Arnold. 

* Pleurotoma dalli Arnold. 

Pleurotoma perversa Gabb. 

* Pleurotoma renaudi Arnold. 

* Pleurotoma smithi Arnold. 

Priene oregonensis Redfield. 

Puncturella cucullata Gould. 

Puncturella galeata Gould. 

Scala indianorum Carpenter. 

Solariella cidaris A. Adan1!". 

Solariella peramabilis Carpenter. 

* Taranis strongi Arnold. 

Terebra simplex Carpenter. 

Thalotia caffea Gabb. 

Tornatina eximia Baird. 

Trophon gracilis Perry. 

Trophon pacificus Dall. 

Trophon stuarti Smith. 

* Trophon orpheus var. prrecursor Arnold. 

Trophon tenuisculpta Carpenter. 

Turritella cooperi Carpenter. 

* Turritella jewetti Carpenter. 

PLEISTOCENE. 

31 

Columbella gausapata var. carinatl· Hinds. 

The marine Pliocene an Pleistocene deposits of California are intimately associated, and at many places glade into each othet~ wit~ no ~erceptible physical break 

between them. At others, owever, an unconformity exists between the two, and 

in some localities the Pleist cene itself may be separated into two divisions, with a 

more or less distinct line o 1 dema~·cation between them. Such a condition as. that 

last mentioned is found in the vicinity of San Pedro, Los Angeles County, where 
32 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

probably the best development of the fossiliferous marine Pleistocene on the 

coast is exposed. This locality is taken, therefore, as the type for the Pleistocene 

of California. 

SAN PEDRO FORMATION. 

TYPE LOCALITY. 

The type locality is vicinity of San Pedro, Los Angeles County, Cal 

NAME AND DESCRI:P'IIION. 

This formation was named and described by W. H. Dall, Table of North American Tertiary horizons: Eighteenth Ann. Rept. U. S. Geol. Survey, pt. 2, 1898, p. 335. 

DEFINITION. 

As redefined by the writer, a this formation includes '' all of the strata of 

Deadman Island and San Pedro lying stratigraphically above the brown Pliocene 

sandstone and below the raised beach formation of Deadman Island." In the 

type locality the San Pedro consists of a series of cong-lomerates and sands, 

both more or less incoherent and extremely. fossiliferous, with a total thickness 

of approximately 100 feet. Near Ventura, beds of probable similar age attain a 

thickness of about 1,000 feet. 

The formation may be divided into two distinct horizons-a lower and-an upperseparated at all points in the vicinity of the type locality by an unconformity. The 

lower part of the formation represents at least the base of the Pleistocene, and may 

possibly extend into the Pliocene. It is probably contemporaneous with the upper 

portion of the Merced, and contains a fauna which appears to be transitional between 

that of the Pliocene on which it rests and that of the characteristic Pleistocene above. 

The upper beds of the San Pedro formation are certainly Pleistocene, and as their 

fauna is more or less characteristic it will be cited as typical of the major portion of 

the Pleistocene. 

LOCALITIES. 

Deposits contemporaneous in a ge_neral way with the Sa~ Pedro formation, particularly the upper division, occur at numerous places along the coast from Alaska 

to Lower California. Only those localities known to be fossiliferous will be cited, 

however. They are as follows: 

Point Holmes, Como?C, Vancouver Island, British Columbia (NewcombeL 

Port Blakeley, near Seattle, ·wash., and other localities in the Puget Sound country. 

Fossil Point, Coos Bay, Oreg. (Dall, 1898, p. 336). 

Ilwaco, near the mouth of the Columbia River, and Newport, Oreg. (Diller, 1896, p. 479 et seq.) 

Fort Ross, Humboldt County. 

Purisima and Punta Afio Nuevo, San Mateo County. 

South shore of San Pablo Bay (unconformably above the San Pablo formation), Contra Costa County. 

Santa Cruz, Santa Cruz County. 

Vicinity of Venturaand Summerland, Ventura County. 

San Pedro, Long Beach, Bells Station, and Los Cerritos Hill, Los Angeles County. 

Newport, Orange County. 

Two miles south of Delmar, Pacific Beach, Spanish Bight, and San Diego, San Diego County. 

a Arnold, Delos and Ralph, The marine Pliocene and Pleistocene stratigraphy of the coast of southern California: 

Jour. Geol., vol. 10, 1902, p. 124. 
J_ 

EISTOCENE FORMATIONS. 33 

FAUNA. 

The fauna of the upper p rtion of the San Pedro. formation consists of species 

which are nearly all found living at the present time. One noticeable thing 

regarding this fauna is t:;he f ct that wherever found it generally contains species 

which, though living, are fou d now only south of the locality yielding the fauna; 

thus indicating somewhat mo e tropical conditions during the Pleistocene than are 

prevalent at the present tim~1 on the California coast. · 

Pecten fizuna.-The Pecten fauna of the upper, or characteristically Pleistocene, 

portion of the San Pedro and equivalent formations is as follows: Pecten alaskensis, 

P_· cattrinus, P. cirmtfaris, a ~ ~ariety ~quisu~cat1~~' P. diegensi8, P. (Hinnites) 

g~ganteus, P. hastat1l8 and v net1es enc~us , h~nrki~, iftavarchus, and strateg1ts, P. 

islandicus, P. latiauritus and varieties cerritensis, delosi, fttcicolu,s and monotimeris, 

P. subnodosus, and P. vogdesi. 

The follo·wing fauna ha 

formation in the vicinity of t 

the Pleistocene for the coast 

been found in the upper beds of the San Pedro 

e type locality, and may be taken as characteristic of 

of California: 

List of S n Pedro formation (Pleistocene) .fossils. 

[Those marked with an asterisk(*) are kno n so far at San Pedro only from the lower portion of the San Pedro formation.] 

ANTHOZOA. 

Caryophyllia arnoldi Vaughan. 

Caryophy llia pedroensis Vaughan. 

Paracyathus pedroensis Vaughan. 

ECHINOIDEA. 

Echinarachnius excentricus Eschsch ,ltz. 

Strongylocentrotus franciscanus AgaBf'iz. 

Strongylocentrotus purpuratus Stimp on. 

PELECYPQDA. 

Aligena cerritensis Arnold. 

Amiantis callosa Conrad. _ 

Angulus buttoni Dall. 

Anomia lampe Gray. 

Area labiata Sowerby. 

Astarte ( Crassinella) branneri Arnol ; 

*Bornia retifera Dall. 

Callista newcombiana Gabb. 

*Callistata subdiaphana Carpenter. 

Cardita ( Carditamera) su bquadrat Carpenter. 

( Lazaria id. } 

Cardium corbis Martyn. 

Cardium elatum Sowerby. 

Cardium procerum Sowerby. 

Cardium quadrigenarium Conrad. 

Chama exogyra Conrad. 

Chama pellucida Sowerby. 

Clidiophora punctata Conrad. 

* Cooperella subdiaphana Carpenter. 

17260-~o. 47-06----3 

PELECYPODA-COntinued. 

Corbula luteola Carpenter. 

Cryptomya californica Conrad. 

Cumingia californica Conrad. 

Diplodonta orbella Gould. 

Diplodonta serricata Reeve. 

Donax californica Conrad. 

Donax lrevigata Deshayes. 

Glycymeris barbarensis Conrad. 

Glycymeris septentrionalis Middendorf. 

*Kellia suborbicularis Montague. 

*Kellia laperousii Deshayes. 

*Kennerlia bicarinata Carpenter. 

·*Kennerlia filosa Carpenter. 

Lrevicardium substriatum Conrad. 

*Leda fossa Baird. 

*Leda hamata Carpenter. 

*Leda minuta var. prrecursor Arnold. 

Leda taphria Dall. 

*Lima dehiscens Conrad. 

Lithophaga plumula Hanley. 

Lyonsia californica Conrad. 

*Macoma calcarea Gmelin. 

Macoma ip.dentata Carpenter. 

Macoma inquinata Deshayes. 

Macoma nasuta Conrad. 

Macoma nasuta var. kelseyi Dall. 

Macoma secta Conrad. 

Macoma yoldiformis Carpenter. 

Mactra californica Conrad. 
34 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

List of ~an Pedro formation (Pleistocene) fossils-Continued. 

l'ELECYPODA-COntinued. 

)tlactra exoleta Gray. 

.Mactra hemphilli Dall. 

Metis alta Conrad. 

Modiolus fornicatus Carpenter. 

Modiolus rectus Conrad. 

*Moerella salmonea Carpenter. 

*Mytilimeria nuttalli Conrad. 

Mytilus edulis Linne. 

*Nerera pectinata Carpenter. 

*Nucula (Acila) castrensis Hinds. 

N ucula suprastriata Carpenter. • 

Ostrea luridaCarpenter. 

*Panomya ampla Dall. 

Panopea generosa Gould. 

Pecten caurinus Gould. 

Pecten circularis Sowerby. 

· Pecten circularis var. requisulcatus Carpenter. 

Pecten hastatus Sowerby. 

*Pecten hastatus var. hericius Gould. 

*Pecten hastatus var. strategus Dall. 

*Pecten jordaniArnold. 

Pecten latiauritus Conrad. 

Pecten latiauritus var. cerritensis n. var. 

*Pecten latiauritus var. delosi n. sp. 

Pecten latiauritus var. monotimeris Conrad. 

Pecten subnodosus Sowerby. 

Pecten vogdesi n. sp. 

Periploma argentaria Conrad. 

Petricola earditoides Conrad. 

Petri cola ( Petricolaria) cognata C. B. Adams. 

Petricola denticulata Sowerby. 

Phacoides ( +Lucin.a) acutilineatus Conrad. 

Phacoides ( +Lucina) californicus Conrad. 

Phacoides ( + Lucina) tenuisculptus Carpenter. 

Pholadidea penita Conrad. 

Platyodon cancellatus Conrad. 

Pododesmus (Mania) macroschisma Deshayes. 

*Protocardia centifilosa Carpenter. 

Psammobia edentula Gabb. 

*Psephis salmonea Carpenter. 

Rupellaria lamellifera Conrad. 

Sanguinolaria nuttalli Conrad. 

Saxidomus gracilis Gould. 

Semele decisa Conrad. 

Semele pulchra Sowerby. 

*Semele pulchra var. montereyi Arnold: 

* Septifer bifurcatus Conrad. 

Siliqua lucida Conrad. 

Siliqua patula Dixon var. nuttalli Conrad. 

·solen sicarius Gould. 

Spisula catilliformis Conrad. 

'spisula falcata Gould. 

PELECYPODA-COntinued. 

Tagelus californianus Conrad. 

Tapes lacineata Carpenter . 

Tapes tenerrima Carpenter. 

Tellina bodegensis Hinds. 

Tellina idre Dall. 

Tellina rubescens Hanley. 

*Thracia trapezoides Conrad. 

*Thyasira gouldii Philippi. 

Tivela crassatelloides Conrad. 

Tresus nuttalli Conrad. 

V enericardia barbarensis Stearns. 

*Venericardia ventricosa Gould. 

Venus tantilla Gould (Psephis id. ). 

Venus (Chione) fiuctifraga Sower by. 

Venus (phione) gnidia Broderip and Sowerby. 

Venus (Chione) neglecta Sower by. 

Venus 1

( Chione) simillima Sower by. 

Venus (Chione) succincta Valenciennes. 

* V erticordia novemcostata Adams and Reeve. 

Y oidia coo peri Gab b. 

*Yoldia scissurata Dall. 

Zirphrea gabbi Tryon. 

GAS'I'EROPODA. 

Acmrea depicta Gould. 

Acinrea in·sessa Hinds. 

Acmrea instabilis Gould. 

Acmrea mitra Eschscholtz. 

Acmrea paleacea Gould. 

Acmrea pelta Eschscholtz. 

Acmrea spectrum (Nuttall) Reeve. 

Actreori (Rictaxis) punctocoolata Carpenter. 

Actreon trask,ii Stearns. 

* Admete gracilior Carpenter. 

* Amalthea aritiquata Linne. (Hipponyx id.) 

Amalthea cranioides Carpenter. 

Amalthea tumens Carpenter. 

Amphissa corrugata Reeve. _ 

* A:IJlphissa ventricosa Arnold. 

Amphissa versicolor Dall. 

Bela fidicula Gould .. 

*Bela sanctre-monicre Arnold. · 

Bittium asperum Gabb. 

* Bittium caJifornicum Dall and Bartsch. 

Bittium filosum Gould. 

Bittium quadrifilatum Carpenter. · 

Bittium rugatU:m Carpenter. 

Bittium williamsoni Arnold. 

Bulla punctulata A. Adams. 

Bulla quoyi Gray, 

* Cadulus fusiformis Sharp and Pilsbry. 

Crecum ealifornicum Dall. 
P EIS'J_'OCENE FORMATIONS. 35 

List of San Ped o formation (Pleistocene) fossils-Continued. 

GASTEROPODA -COntinued. 

Cmcum crebricinctum Carpenter. 

* Crecum magnum Stearns. 

Calliostoi:na annulatum Martyn. 

Calliostoma canaliculatum Martyn. 

Calliostoma costatmn .JtJ.artyn. 

Calliostoma gemmulatum Carpenter. 

Calliostoma tricolor Gabb. 

Cancellaria cooperi Gabb. 

Cancellaria crawfordiana Dall. 

Cancellaria tritonidea Gabb. 

Cerithidea californica Haldemann. 

Chlorostoma aureotinctum Forbes. 

Chlorostoma brunneum Philippi. 

Chlorostoma funebrale A. Adams. 

Chlorostoma funebrale var. subapertu n Carpenter. 

Chlorostoma gallina Forbes. 

Chlorostoma montereyi Kiener. 

Chlorostoma pulligo Martyn (Phorc s id. ). 

Chlorostoma (Omphali us) viridulun var. ligulatum Menke. 

Chorus belcheri Hinds. 

Ghrysodomus rectirostris Carpenter. 

* Chrysodomus tabulatus Baird. 

Clathurella conradiana Gabb. 

* Columbella (Astyris) californiana 

Columbella (JEsopus) chrysalloidea arpenter. 

Columbella (Astyns) gausapata Gou d. 

Columbella (Astyris) gausapata carinata 

Hinds. 

Columbella (Anachis) minima Arnol1d. 

* Columbella (JEsopus) oldroydi Ar~old~ 

Columbella solidula var. prrecursor 4 rnold. 

Columbella (Astyris) tuberosa Carpe ter. 

Conus californicus Hinds. 

Coralliophila nux Reeve. 

* Crepidula aculeata Gmelin. 

Crepidula adunca Sowerby. 

Crepidula dorsata Broderip. 

Crepidula princeps Conrad. 

Crepidula onyx Sower by. 

Crepidula rugosa Nuttall. 

Crucibulum spinosum Sowerby. 

* Cryptochiton stelleri Middendorf. 

Cylichna alba Brown. 

Cyprrea spadicea Gray. 

* Cythara branneri Arnold. 

Dentalium indianorum Carpenter. 

Dentalium neohexagonum Sharp an Pilsbr'y. 

Dentalium pseudohexagonum Dall . . 

Dentalium semipolitum Broderip an Sowerby. 

* Diastoma, sp. indet. 

Drillia cartcellata Carpenter. 

GASTEROPODA-COntinued. 

Drillia hemphilli Stearns. 

Drillia inermis Hinds. 

Drillia inerrnis var. penicillata Carpenter. 

Drillia johnsoni Arnold. 

* Drillia merriarni Arnold~ 

* Drillia montereyensis Stearns. 

Drillia pudica Hinds. 

Drillia torosa Carpenter. 

Erato columbella Menke. 

* Eulima falcata Carpenter. 

Eulima hastata Sowerby. 

Eulima micans Carpenter. 

Eupleura muriciformis Broderip. 

Eupleura muriciformis var. curta Arnold. 

Fissuridea aspera Eschscholtz. 

Fissuridea inrequalis Sowerby. 

F~'Ssuridea murina ( Carpe?ter) Dall. 

F1ssurella volcano Reeve. I · 

Fusus barbarensis Trask. I 

Fusus luteopictus.Dall. 

Fusus ro bustus Trask. 

'~ Fusus rugosus Trask (=F. arnoldi Oossmann). 

Gadinia reticulata Sowerby. 

Galerus mammillaris Broderip. 

Ha.liotis fulgens Philippi. 

Haminea virescens Sowerby. 

Helix: (Epiphragmophora) sp. indet. 

Isapis fenestrata Carpenter. 

Ischnochiton regularis Carpenter. 

*I vara turricula (Carpenter) Dall and Bartsch. 

Lacuna compacta Carpenter. 

Lacuna porrecta Carpenter. 

Lacuna solidula (Loven) Carpenter. 

* Larnellaria stearnsii Dall. 

Leptothyra bacula Carpenter. 

Leptothyn~. carpenteri Pilsbry. 

* Leptothyra paucicostata Dall. 

Litorina planaxis (Nuttall) Philippi. 

Litorina scutulata G~mld. 

Lucapina crenulata Sowerby. 

Lucapinella callomarginata Carpenter. 

Macron kellettii A. Adams. 

Macron lividus A. Adams. 

Mangilia angulata Carpenter. 

Mangilia hooveri Arnold. 

Mangilia interfossa var. pedroana Arnold. 

Mangilia interlirata Stearns. 

* Mangilia oldroydi Arnold. 

* Mangilia painei Arnold. 

* Mangilia sculpturata Dall. 

Mangilia striosa C. B. Adams. 

Margarita optabilis var. knechti Arnold. 

·' 
36 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

Li.~t of San Pedro formation (Pleistocene) fossils-Continued. 

GASTEROPODA -continued. 

*Margarita optabilis var. nodosusArnol~; 

Margarita parcipicta var. pedroana Arnold. 

Marginella jewettii Carpenter. · 

Megatebennus bimaculatus Dall. 

Mitra maura Swainson.' 

* Mitramorpha filosa Carpenter. 

* Mitramorpha intermedia Arnold. 

Monoceros engonatum Conrad, 

Monoceros lapilloides Conrad. 

Mopalia ciliata Sowerby. 

Murex (Pteronotus) festivus Hinds. 

Murex ( Pterohytis) foliattis Martyn. 

Murex (Pterohytis) nuttalli Conrad. 

Murex ( Chicoreus) 'leeanus Dall. 

Murex (Cerostoma) monoceros Sowerby. 

Murex trialatus Sowerby. 

N assa .californiana Conrad. 

Nassa cerritensis Arnold. 

N assa fossata Gould. 

Nassa insculpta Carpenter. 

Nassa mendica Gould~ 

Nassa mendica var. eooperi Forbes. 

Nassa perpinguis Hinds. 

Nassa tegulaReeve. 

Nassa versicolor var. hooveri Arnold. 

* Natica clausa Broderip & Sowerby. 

Natica (Lunatia) lewisii Gould. 

Ne,rerita recluziana Petit. 

N orrisia norrisii Sower by. 

* Ocinebra barbarensis Gab b. 

Ocinebra foveolata Hinds. 

Ocinebra interfossa Carpenter. · 

Ocinebra keepi Arnold. 

Ocinebra lurida Middendorf; 

Ocinebra lurida var. aspera Baird. 

·. Ocinebra lurida var. cancellina Philippi. 

Ocinebra lurida var. cerritensis Arnold. 

*Ocinebra lorida var. munda Carpenter. 

Ocinebra micheli Ford. 

Ocinebra perita Hinds. 

-, Ocinebra poulsoni Nuttall. 

*Odostomia gouldii Carpenter. 

*Odostomia nuciformis var. avellana Carpenter. 

Odostomia tenuis Carpenter. 

Olivella biplicata Sowerby. 

Olivella intorta Carpenter. 

Oli vella pedroana Conrad. 

Opalia borealis Gould. 

Opalia crenitoides var. insculpta Carpenter. 

Pachypoma imequale Martyn. 

Paludestrina curta Arnold. 

Paludestrina stokesi Arnold. 

GASTEROPODA-continued. 

Phasianella compta Gould. 

*Physa hete:rostropha Say. 

Pisania fortis Carpenter. 

Planorbis tumidus Pfeiffer. 

Planorbis vermicularis Gould. 

Plenrotoma (Borsonia) bartschi Arnold. 

Pleurotoma (Dolichotoma) carpenteriana Gabb. 

Pleurotoma (Dolichotoma) cooperi Arnold. 

*Pleurotoma (Borsonia) dalli Arnold. 

*Pleurotoma (Borsonia) hooveri Arnold. 

*Pleurotoma (Leucosyrinx) pedroana Arnold. 

· Pleurotoma .. perversa Gabb. 

*Pleurotoma ( Drillia) renaudi Arnold. 

*Pleurotoma-{Spirotropsis) smithi Arnold. 

Pleurotoma (.Dolichotoma) tryoniana Gabb. 

Pomaulax undosus Wood. 

Priene oregonensis Redfield. 

Pu:ricturella cucullata Gould. 

*Puncturella· galeata Gould. 

Purpura crispata Chemnitz. 

Purpura saxicola Valenciennes. 

Pyramidella conica var. variegata Carpenter. 

Ranella californica Hinds. 

Rissoa acutelirata Carpenter. 

Scala bellastriata Carpenter. 

Scala crebricostata Carpenter. 

Scala hemphilli Dall. 

Scala hindsii Carpenter. 

Scala indianorutn Carpenter. 

Scalatincta Carpenter~ 

*Seila assimilata C. B. Adams. 

Serpulorbis squ,amigerus Carpenter. 

Sigaretus -de bilis Gould. 

Siphonalia ~ellettii .Forbes. 

Spiroglyphus lituella Morch. 

* Styliferina tenuisculpta Carpenter. 

Taranis strongi Arnold. 

Terebra (Acus) simplex Carpenter. 

* Thalotia caffea Gabb. 

Tornatina cerealis Go~ld. 

Tornatina culcitella Gouid. 

Tornatina harpa Dall. 

Triforis adversa Montague. 

. Trivia californica Gray. 

T:rivia solandri Gray. 

Tritonium gibbosus Broderip. 

Trophon (Boreotrophon) cerritensis Arnold. 

* Trophon ( Boreotrophon) gracilis Perry. 

Trophon (Boreotrophon) multicostatus Escl:r-

. scholtz. 

* Trophon orpheus var. prrecursor Arnold. 

Trophon ·. ( Boreotrophon) pedroanus Arnold. 
GEOLOGIC RANGE OF CALIFORNIA PECTENS. 

List of San Pedro formation (Pleistocene) fossils-Continued. 

G ASTEROPOD A -COn tinned. 

Trophon ( Boreotrophon) pacificus Dall. 

* Trophon stuarti Smith. 

GASTEROPODA-COlltinued. 

Turbonilla subcuspidata Carpenter. 

Turbonilla tenuicula Gould. 

* Trophon ( Boreotrophon) triangulatus Carpenter. * Tnrbonilla torquata Gould. 

* Tnrbonilla adleri Dall & Bartsch. 

* Turbonilla arnoldi Dall & Bartsch. 

* Turbonilla torquata var. stylina Carpenter. 

Tnrbonilla tridentata Carpenter. 

Turbonilla aurantia Carpenter. 

Tnrbonilla crebrifilata Carpenter. 

Turritella cooperi Carpenter. 

Tur~itella jewetti Carpenter. 

* Turbonilla gibbosa Carpenter. * V ermicularia, sp. indet. 

Turbonilla laminata Carpenter. Vitrinella williamsoni Dall. 

Turbonilla latifundia Dall & Bartsch. Volvarina varia Sowerby. 

Turbonilla lowei Dall & Bartsch. *Valvula cylindrica Carpenter. 

Turbonilla muricata Gould. 

* Turbonilla pentalopha Dall & Bartsch. 

Tnrbonilla similimis C. B. Adams. 

Turbonilla stearnsii Dall & Bartsch. 

PI ~CES . 

Urolophus halleri Cooper(?) 

GEOLOGIC RANGE OF CALIFORNIA PECTENS. 

Range of species and var·ieties. 

[?shows limits somewhere between which the species belongs.] 

Recent I Pleisto-J · cene. 1 Pliocene. Miocene. I Oligocene. Eocene. 

37 

L. . I San lvmg. Pedro. 

I 

Mer- r Purisiced. i ma. San · Monte- Vaque- San Lo- Tejon MartiPablo. rey. ros. renzo. · nez. I --- - - ------

Pecten: I 

alaskensis Dall . -.. -. - - .. - -. - Htt tttt .... -- ----- ----- ------ ------ ------1- - - - - - - - - - - -

andersoni n. sp: -- ___ - _ .... -. . _____ . -. -...... --I----- tt tttt tttt ------ ------ ------

ashl:;;~~a::~~~~~~:-~--~~~~~~ ~~~~~~ ~~~~~~ ---~~- -~~~~- ~~~~~~ ~~~~~~ -~~~~- ~~~~~~ ~~~~ ~~ ~~~~~~ auburyi n. sp ------- ---- ... - ... _ .. -.... _ ----.- tttt -----_ I_----- ------ ------ ------ ------

bartschi n. sp _ . -. --- ------- - --- --- ------ ---- -- tttttttt _- -- -_ -_-_· _- I_- _- -- -- -- -_

1 

-_ -_. _- _- _- _- _- _- -__ - _- -- ~ ~ ~ ~ ~ ~ ~ -_ -_ -_ -- -- bell us Conrad ... - - -.. - _- .. - - . -- __ .... --. tt 

bellilamellatus n. sp _ . ___ -. _ . . . _ . . . . _ . __ . tt tttt ------ --. --- -- --- ------ ------ ------

:~::;~in~_s:~~~~~~~~~~~~~~~~ ~~~~~ ~~~~~~ ~~~~~~ ~~~~ ~~~~~~ -~~~~- ~~~~ -~~--- ~~~~~~ ~~~~~~ calkinsi n; sp __ .- .. __ .. _ ... ___ .. __ .. _. _ ...... _ .... _ .. __ --. ---- . - . ----I-----. tttt 1 ------

carrizoensisn. sp _ _. __________ ------------------ -·----- ???? ???? ???? 1------ ------------

caurinus Gould------ ------- - tttt tttt tttt tttt --- --- ------ -----I---- -- - - - --- ------

cerrosensis Gabb- ----- _---- .. ____ .. ----.. tt tttt ------ ------ ------ -- •--- ------ ------ var. mendenhalli n. var __ ------------ ------------ ???? ???? ???? ------ ______ [ _____ _ 

circularisSowerby ___________ tttt tttt ???? ?? ------------------------------------

var. requisulcatus Cpr---- tttt tttt 

clallamensis n. sp _______ . ____ .. ____ .. ~ __ . ____ ..... __ .. __ --- .. ---- tt tt ------ ------

<;:oalingaensis n. sp. __ -.... - _ _ .. - __ . . . _ -. _ . -. . . . tttt ------ ------ ------ ------ -----· -----· 

cooperi n. sp - - - ----- - - ----- - - - - - - - - - - - -- tt i tttt ---- -- --- --- ---- -- ------ ------ · ----- coosensisShumard ___________ ------I------ 1 ••••• J . ____ tttt ------------------------ -----
38 TERTIAE.Y AND QUATERNARY PECTENS OF CALIFORNIA. 

Range of species and varieties-Continued. 

l? shows limits somewhere between which the species belongs.] 

Recent. p~!~~- Pliocene. MioceJ!e. Oligo-] Eocene. cene . . I 

- -

Living. P~d~o. Mer- Purisi- San Monte- Vaque- San Lo- Tejon Marticed. rna. Pablo. rey. ros. renzo. · nez. 

. . . Pecten--Continued. . I I 

crassicardo Conrad ............ ___ ............. - .. --- - tttt tttt tttt ------j----------. -

var. hamiltonin. var .... 

1 

______ ------------------ tttt ???? ???? ----------------- -

::::.~:io~~~:~~~~~~~~~~~~~~~~ -~~~~- ~~~~~~ ~~~~~~ ~~~~~~ ·;;;;· ·;;;;· ·;;;~- ~~~~~~ ~~~~~~ ~~~~~~ . diegensis Dall. -----'--- - ----r tttt tttf I· -----. -----------------: ------------I-~ ---. -----. dilleri Dall ___ _ . ___ , _ _ _ _ _ _ _ _ -. _ _ _ _ _ _ __ : _ _ _ _ _ _ _ _ ? ? ? ? ? ? ? '? • _ _ _ _ _ _ ____ . ______ . _____ . _ : ___ _ 

discus Conrad ....•.. " ..... _ . . _ _ _ _ _ . _ . _ _ _ _ _ . . . . . .... -. tttt ? ? ? ? . - - - - - - - - -- -; - - - - - . -- - -- -

eldridgei n. sp -------------------------------------- tttt ------------------1------------

estrellanus Conrad .. ___ .. __ . · ______ .. _ ....... _ ....... tttt _t_t_t_t_- _t_. t_t_t __ · _- _- _- _- _- -- ~- -- -- _- _- ,_- ~ _- -__ -_-_-_-_- · var. catalime n. var _____ ._ ~ ____ .. ~ __ ... _... tt tt 

var. terminus n. var _____ . _____ . _____ . __ ... . . . . . . tttt ...... ------ ------ ------ -.---. 

· excavatus Anton ............ tttt . -- .· .. -_----.

1

.----- . ----- --.-- - __ - -_- - · ·----: ----- ----- · 

fucanus Dall . ___ . __ ." __ . ____ .. __________ ... _________ . ???? ???? ???? . _____ ... __ . _____ _ 

giganteus Gray---- .. -... -.. tttt tttt tttt tttt tttt tttt tttt j------ ------ ------ hamlini n. sp -------------- ·:·--- ------------------ ???? ???? ???? j------1----- -J- ----- .hastatus So~erby ----------- tttt tttt tttt tttt -------------.----- --·- ·~--- ---- ,­

var. al b1d us Dall n. var. tttt . . . . . . . ----- ~ -~ --_- .------ ------ ------ ------

1

- - - - • - - - - - - · 

var. hericius Gould ..... . tttt tttt tttt tttt tt . -.----- ------ ------ ---- -----

var. hindsii Carpenter.. tttt tttt tttt tt ------------ ----'-- ------ 1------1------

~n;;~~:Wtft~~l:::: ;;;;: : ;~;;: : ;;::: . ~~;~. :::: :" ::::: :_:::::: ::::: t tttt :1:::::: 

islandicus Muller ... --- .... -. tttt tttt tttt tt ------ ------ ------ ------ ------'------ jordani Arnold ____________ _ tttt tt 

keepi n. BP---------~-- ----- ---·· ------------------ ???? ???? ???? 

landesi n. sp .......... _ . . . . ____ ... _ ... ____ . _ .... ~ ........ - - -·_ - - -. - -. . - - --- tttt . ---. -

latiauritus Conrad.-.-- ... -- tttt tttt tttt tt ------ ------ -- _._-- ------ . ---- -I------

var. cerritensis n. var __ _ 

var. delosi n. var ______ _ 

var. fucicolus Dall. ___ • _ 

var. monotimeris Con __ 

lawsoni n. sp _______ ~ _____ _ 

lecoi:ltei n. sp . ____ . ____ , __ _ 

lompicoensis n. sp. ________ _ 

lompocem;is n. sp _ ~ _______ ._. 

tttt 

tttf 

tttt 

tttt 

tttt - ... -...... -........... - .. --- .... --.· ........ -... -......... ----- ........... --... ----

ttt-t tttt ------ ------ ------ ------ ------ ------ ------ ------

----- ------ ------ tttt ------- -:---- ------ . ----- --·_ --- -----. 

.. ::: :::::: :::::: :~t~~:,_:::J:~: -~~~- :::::: :::::: :.::::: 
GEOLOGIC RANGE OF CALIFORNIA PECTENS. 39 

Range of species and mr-ief'ies-Continued. 

['? shows limits somewhere between which the species belongs.] 

Recent. Pcleeritseto. · Pliocene. Miocene. I Oligo1 Eocene. I cene. 

~ San Mer- Purisi- -San Monte- Vaqu:

1

1san-Lo-[ Tejon I Marti- IVm · Pedro. ced. ma. Pablo. rey ros. renzo. ; · nez. 

. ------ ---1- - Pecten-Continued. I ' I · ! .·1 

magnolia Conrad . ___ . __ .... -1-.... -l-... --1--. --- . ----l ----------- tttt ------! - - - - - -l------

:~;:~~~8~~ =p;~:::::::::: ::':::: ::! :: :J: ::: -ttt:_ ::::::I:::::: 1-~t~~- :::::: :::::: ::::: 

neahensis n. SP-------~- ---- ------ ------1------ ---·--- ???? [ ???? ???? 1 ...... 1 ...... • ------

nutteri n. sp ....... _.. . . . . . . .... i .. . . . . tt 1 tttt tttt 1 .. ---- ------ - - ---- ------' - -----

opun~ia Dall ... _ .... -.-. ; -. . ... -_ I_-----.

1 

tt tt ----- -j- --- ~- · ·---: · ·---- ---- ~ '!- ---· · ow em n. sp .. ---.----- ..... - ..... - ........ ---. tttt tttt 

1 

.. --- -- ------ ------ ----- ~ 1------

pabloe~Bis Conrad ___________ ------ ------ 1.------ -- ---~ tttt ------ -----· ------------ ..... . 

palmen _Dan .. ________ .. -- -. ! tttt . -----1------ .. ---l ---- · ---------- -- -- -- · -----I - _- - - - • 

~:::~:~:~t~:l~~~~~~~~~ ~ ~ ~ ~ ~ >-~~~~- ----- --~~ -1-t~~~ ---- -~~~~~ ~~~~~~ ~~:~~~ ~ ~ ~ ~ ~ : : : ~ ~ ~ peckhami Gabb - ..... - . -.--- . _ .. - . _.-. ;

1

_.--- tttt tttt tt . -. ---i. ----- pedroanusTrask _____________ ----- ------ tttt tttt tttt ------------------ -----· 

pernm n. sp. - --- -... - - --__ . _ ...... -- -- . . __ . _ _ . -. ???? tttt .

1

_ - -- - ~ - - - - .

1 

.... - -

proavus n. sp.--- .. -...... -. · ,·---- .... -. --_ -_ -_ -_ ·_ r_ -_ -_ -_ -_ . ---- -.---- .. --- -----. i tttt 

propatulusConrad ___________ 1 _____ ---- ???? ???? ???? 1------ ---··· ------ t 

~:::~:~:n~~ ;1~ _ ~~ ~ : : : : ~ : : : : . ~~~~ _ ___ _ _ _ _ __ tttt : :: : :: -: : : : : : : : : : t : : : : J ~ : ~ ~ J : ~ : : : 1 I . I 

var. tillamookensis n. var. tttt . ---- ----- ------ ----- J ------

riversi n. sp. ___ . _____ . ______ .. ___ 

sanctfficruzensis n, sp ___ . ____ ... __ 

sespeensis n. sp _________ .. _ ... ___ . 

var. hydei n. var_ ___________ _ 

stanfordensis n. sp . _ . _ ...... ! . . . . . . . . ___ . . ..... _ : __ .. 

stearnsii Dall ______ . __ ... _ . _

1

__ _ __ tt 

subnodosus Sowerby _. _. _--. tttt 

turneri n. sp ____ . _______ . _ .... ___ . ?? 

vancouverensis Wh~eaves _. tttt 

vaughani n. sp. __ ... __ .. __ _ 

veatchii Gabb. ___ . ____ . ____ . 

vogdesi n. sp ________ . __ . ____ . ____ . ???? 

wash burnei n. sp ______ . ____ -I-___ . . ___ _ 

watt:~:· 1:~~~~~ ~-- ~~~ ~ : ~ :: : : i: ~ ~ ~ : ~ [: ~ ~ ~ : . ! - - - - - • 

----. tttt 

----- 1------ -----

' tt 

~~~- -~ ~ : ~ J : : : : : : 

~::~~ ::::~~ ::~::: 

------ ------ j·-----

----- ------ --- ---

-.. --- -........ -- .... ----

tt -----· I • - - - - -

-i _ wayland! n~--:-- __ ::~~ +--- --1-____ -I-___ _ ~---- -- --~--~----------C----~---------- ----
40 'l'ERTI.ARY .AND QUA TERNARY PECTENS OF O..ALIFORNI..A. 

Summary of range of species and varieties. 

Species found in the Eocene ..... _______ . ___ . _______ . _ .............. __ . ______ . _ . __ . ___ . _ _ _ _ 4 

Species found only in the Eocene·---·-·-··········----···----············---.-·-··---··-----· 4 

Species transitional between the Eocene and Oligocene . _ . _ ~ .. _ .... ___ ~ _ .. _ . __ . ___ . ___ .. . . __ ~ None. · . . -

Species found in the Oligocene ...... ___ ._ ... _ .... __ .. ___ ... _._ ... _._._._ .' ... __ .. _. __ .. __ 5 

Species found only in the Oligocene _____ .. ___ . _______ .• ~ .. _____ ..... __ . _. ____ . __ . _ ~ _. __ ~ __ . None. 

Species transitional between the Oligocene and Miocene _. ___ . __ ... __ ... ____ . __ . _. _. _ . ___ . __ _ 5 

Species found in the Miocene .. ~. _________ ~ _ ~ _. __ . ______ . _ _ _ ...... - ..... _ ........ _ ....... . 32 

Varieties found in the Miocene. _ .... __ . _ .. _ .... ___ ...... ~ . _ . _ .................... : -........ . 6 

Species found only in the Miocene. ___ .. _. __ ....... __ . . _._._. __ ........ _ .. _ ........ _ ....•... 23 

Varieties found only in the Miocene_ ..... _ .... _ .. _ . .. ~. _ .... _ ....................... ..... . 5 

Species doubtfully Miocene .. _. _. _. _ ~ _ ... __ .. _ .. __ ....... _. _ ..... _ .. _ . __ ........... ____ ! ...• 1 

Species transitional between the Miocene and Pliocene ........ ~ ... _ ............ _ ........... . 4 

Varieties transitional between the Miocene and Pliocene ......... _ ...... __ . ~ . _ ..... _ ...... __ 2 

Species doubtfully transitional ...... ____________ .. _. _ ... _ .... .. _ ....... . .. __ .. _ ........ ___ . 1 

Species found in the Pliocene~ _ . _ . __ . __ . _ . _ ... _ . _ .... ___ . _ . _ ~ .. __ ... _ ............ _ .. _ ...... - 31 

Varieties found in the Pliocene __ . ___ .. __ .. ~ .. ___ .. ~. _ ..... _ .................. · ............ . 6 

Species found only in the Pliocene .... __ ........... ___ .................... __ ... _ ~. _ ..... _ .. _ 23 

Species doubtfully Pliocene. ___ . _ ... _ .... _. _ .. __ .. _-_______ ....... __ ...... _ .... _ ... _ .... _ .. . 2 

Species transitional between the Pliocene and Pleistocene .. _ ..... _ .............. : ...... ~ .... . 7 

Varieties transitional between the Pliocene and Pleistocene .......... _ ... _ .. __ ............ __ _ 3 

Species doubtfully transitional ...... _ .................... __ . ___ . _ .. __ ... ____ .. _ .... __ .. __ .: 2 

Species found in the Pleistocene ... _ ... __ . _ . __ . _ ... _ ....... _ .......... . ..... __ ..... _ ..... _ .. 11 

Varieties found in the Pleistocene .. __ ..................• _." ... : ............ -.. _ .. _ -.· ... _ .. . 9. 

Species found only in the Pleistocene .. _ ...... _ . ........ __ ........... _ .......... -·-..... _ ... . 1 (?) 

Varieties found only in the Pleistocene .. __ ...... _ ....... ___ . __ .. _ .. ___ . __ ....... _ . __ .. ____ _ 1 . Species transiti~nal between Pleistocene and Recent.. _____ ....... _._ ....... __ ..... _ .. _ ... __ _ 9 

Varieties transitional between Pleistocene and Recent _ .. __ . _. _ ... . ................... __ . ___ _ 8 

Species found in the Recent fauna. ___ ... ___ ._ ... __ ......................... _ ..... _ ... _ .... . 15 

Varieties found in the Recent fauna ........ __ .. ___ ... ____ . __ ......... " ........ _. _ ..... _. _ .. _ . 10 

Species found only in the Recent fauna ...................................... _- ............ . 7 

Varieties found only in the Recent fauna ....................... _. ~ .· ....................... . 2 

Species found from Recent to Pliocene fauna ( 1 doubtful) ................................... . 6 

Varieties found from Recent to Pliocene fauna ... _ ....................... ~ ... . ·_ ............ . 4 

Species found from Recent to Miocene fauna .............. , ...... . ......... .. .......... " .. . 1 

Varieties found from Recent to Miocene fauna .. ~ ." .. _ ....... : ....•......................• __ . 1 
PART II: 

SYNOPSIS AND DESCRIPTIONS OF SUBGENERA AND SPECIES.a 

, SYNOPSIS OF SUBGENERA AND SPECIES. 

)>age. 

Class PELECYPOD A ... --....... ------ ---- -- ------ ------- . ----- -------------------------- 45 

Order P RIONODESMA CEA ____________ .. ________________ ______________ . _____ . _ .. _. _ _ 45 

Superfamily PECTINACEA .... __________ ----- _____ .. _______ --- ___ .... . __ --- .. ---- 45 

Family PECTI~ID..E .. ____ . ________ . __ c _______ • ________ •• ______ •• • • _ • __ . • _ • • • • • • 45 

Genus Pecten MiiUer. _____ . ____ . ___ . _. _ .. . ... ___ . ___ . _. __ ...... __ . __ . _____ . 45 

Subgenus Pecten s . . s. Muller._. ___ . . ..... _. ___ . . .. __ .. ___ .. . . . . . . . . . . . . 48 

Patinopecten Dall. ______________________ ... _________ . . _____ . _ _ _ _ _ _ 48 

Nodi pecten Dall __________ . ______________ -.-. .. ___ •. ___ . __ . _.. . .... 49 

Chlamys Bolten _____ . _________________ .. __________ . _____ . _ _ _ _ _ _ _ _ 49 

Lyropecten Conrad. _____ . ___________ ........ _._ .. ___ ...... _ ..... _. 49 

JEquipecten Fischer ______ . ___ _ . ___ . ________ ... ___ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 49 

Plagioctenium Dall. __ .. _ .. _________ . ____ . _. ____ . __ . ___ ... _. _. __ . _ _ _ 50 

Pseudamusium H. and A. Adams ____ ._ ............................ ~ 50 

Amusium Bo.lten. ________________ . ___ . _ .. _ . 1 . _____ ................ 50 

Propeamusium Gregorio. _____ . __ . ____ .... _._ ....... . . _ .. ________ ._ 50 

Hinnites Defrance ___ . __________________ ... __ .. _ .. ___ . _____ .. _ _ _ _ _ 50 

Eocene Pectens_. _____ .. ___ . ______ . ______________ .... __________ .. ____ . 51 

P. (Chlamys) calkinsi n. sr- --------------------------------------- 51 

P. (Chlamys) landesi n. sp ---------------------------------------- 51 

P. (Chlamys) proavus n. sp. _. _________________ ... ___ . ____ . ____ . _ _ _ 52 

P. (Propeamusium) interradiatus Gabb. _. _. ___ ....... _. _______ ... _ _ 53 

Oligocene Pectens ______ . _____________ . ____ .. ___ .. __ .. __ ...... __ .... ~ _ _ 54 

P. (Pecten) sanctrecruzensis n. sp . __ .. __ . ______ . _ . _ ... _ ..... - -. . . . . 54 

P. ( Chlamys) branneri n. sp. ___ .. ___ ..... ___ .. __ . __ ... ___ _ : _ ... _ _ _ 55 

P. (Pseudamusium) peckhami Gabb __ . _ .. _ ...... _. _. ________ .. _ _ _ _ 56 

P. ( Propeam usi um) clallam ens is n. sp _ ..... ___ .... __ .. __ . ...... _ .. _ 57 

P. (Propeamusium) waylandin. sp --------------------------- ----- 58 

Miocene Pectens _____________ . ___ .. ____ . _ . ______ .. ____ . _ .. _ . ____ ..... _ 59 

P. (Pecten) carrizoensis n. sp _________ .. _____ ... __ . _ . .. _____ . _____ . 59 

P. (Pecten) keepi n. sp .... __ ........ .... _ .. _ ..... _ . _ .......... _ _ _ _ 60 

P. (Pecten) san ctrecruzensis n. sp. (persists from 0 ligocene) ___ . ____ . 60 

P. (Patinopecten) coosensis Shumard. ___ ... __ ............. _ ...... _. 61 

P. (Patinopecten) dilleri Dall (?) . _ •••..... __ ....... _ .. . ......... _ _ 62 

P. (Patinopecten) oweni n. sp : ..... ___ . ___ ... _______ .... ____ ...... 63 

P. (Patinopecten) propatulus Conrad._ .. _. _____ . ___ -- .... -- __ ... --- 64 

P. (Chlamys) branneri n. sp. (persists from Oligocene). _________ . __ . 55 

P. ( Chlamys) fucanus Dall . __________________ . _______ "'"" ___ . _ _ _ _ _ _ 66 

P. ( Chlamys) hamlini n. sp ____ .. ________ . ___________ ... _ .... ____ . _ 67 

P. (Chlamys) hastatus var. hericius Gould ______________ . . __ ... ___ .. 110 

P. ( Chlam ys) n utteri n. sp . _________ . _____________ .. __ ______ ... __ . 67 

P. ( Chlam ys) sespeensis n. sp ___________ . ________ . ________________ . 69 

P. (Chlamys) sespeensis var. hydei n. var___________ _______________ 69 

a The description of each species will be found under the heading of the epoch in which the species is first known 

to occur. Any species persisting into a following epoch will be listed in the synopsis also under the heading of the 

latter with an explanatory note. 

41 
42 TERTIARY AND QUATERNARY PECTENS ·Oil' CALIFORNIA. 

Class PELEOYPODA -Continued. 

Order PRIONODESMACEA-Continued. 

Superfamily PECTINACEA-Coutinued. 

Family PECTINIDJE-Continued. 

Genus Pecten M tiller-Continued. 

Miocene Pectens-Continued. Page. 

P. (Lyropecten) bowersin. sp -----············-----······--------- 70 

P; (Lyropecten) crassicardo Conrad ................ ,. __ .. ______ ___ _ . 71 

P. ( Lyropecten) crassicardo var. hamiltoni n. var ______ .. _ .. __ .. ___ . 73 

P. (Lyropect~m) estrellanus Conrad ___ . ___ . ______ ... _ .... ____ .. _. _ _ 7 4 

P. (Lyropecten) estrellanus var. catalinre n. var. ____ .... _ ....... ___ . 76 

P. (Lyropecten) estrellanusvar. terminusn. yar..: .... "-····-······· 77 

P. (Ly:ropecten) magnolia Conrad --------···· ····-------·····---- 77 

P. (Lyropecten) miguelensisn. sp ....... ·-··--·--·------·-···---·---- 79 

P. (Lyropecten) perrini n. SP-----·-----------··-·-- -- ~- -···--·---- 80 

P. (Lyropecten) vaughani n. sp .................... ······-----·---- 81 

P. (Plagioctenium) andersonin. SP---------·----·-············----- 82 

P. ( Plagioctenium) andersoni var. barkerianus n. sp .. .. ........ _ _ _ _ 83 

P. ( Plagioctenium) cerrosensis var. mend'enhalli n. var ~ _ .. ___ .... __ . 84 

P. (Plagioctenium) deserti Conrad ~ _. ________ . _ . . _ .. _ .. .. ..... _ _ _ _ _ 85 

P. ( Plagioctenium) discus Conrad_._ .. _. __ ; .... ___ .. ___ ........ _ _ _ _ 86 

P. (Plagio.cteniuin) eldridgei n. sp ___ . ________ .-. _ ........... _ .. _. _ _ 87 

P. ( iplagio.c.tenium) neahensis n. sp .. · _. _ ~. ____ .. __ ". _ ......... _. __ . _ 87 

P. ( Plagioctenium) pabloensis Conrad ___ ........ .". _ ......... _ .. _ _ _ _ 88 

P. (Pseudarnusium) lornpicoensisn. SP---------------··········---- 89 

P. (Pseudamnsium) pedroanns Trask _. ____ .. _ ........... _ ....... __ 90 

P. (Pseudamusium) peckhami Gabb (persists from Oligocene) ____ ._. 5G 

P. (Propeamusinm) clallamensis n. sp. (persists from Oligocene)..... 57· P. ( Propearnusium) stanfordensis n . sp ______ .. __ ... _________ .. _ _ _ _ _ 91 

P. ( Propearnnsinm) waylandi n. sp. (persists. from Oligocene) ___ ... _ 58 

P. (Amnsium) lompocensisn. sp ....... ----············------------- 92 

P. (Hinnites) gigantensGray...................................... 93 

Pliocene Pectens ... _. _ ......................................... _ .... _. 94 

P. (Pecten) anbnryin. sp ...... ." ......... . .......... ·-···-------- 94 

P. (Pecten) bell us Conrad ..... _ ... ___ . . . . . . . . ..... _ ... _ ...... _ ... _ 95 

P. (Pecten) coalingaensis n. sp ........ _ .......... _ ............ _.... 97 

P. (Pecten) hemphilli Dall ............................ _ .... _. ·.; .. _ 97 

P. (Pecten) lecontei n. sp. __ ...... _ ..... _ .................. _ ... ___ . 98 

P. (Pecten) merriamin. sp........................................ 99 

P. (Pecten) stearnsii Dan:._ .. _ ...... _ ...... _ ...•.......... ___ ..... 100 

P. (Pecten) vogdesi n. sp.......................................... 100 

P. (Patinopecten) caurinus Gould ...... _ ... __ ................ _..... 101 

P. (Patino pecten) tlilleri Dall (persists from the Miocene ? ) ....... __ . 62 

P. ( Patinopecten) healeyi n. sp _ .. _ ....... _ .............. _ ....... . 103 

.P. (Patinopecten) oweni n. sp. (persists from Miocene) . . . . . . . . . . . . . 63 

P. (Patinopecten) purisimaensis n. sp _. __ .......... _ ·- _ .. _. __ . __ .... 105 

P. (Patinopecten) turnerin. sp ----·----··:···········------------- 106 

P. (Nodipecten) veatchii Gabb ----------·-----···------------------ 106 

P. (Chlamys) bartschin. sp -----·-···--····-·------···--·-····---- 107 

P. ( Chlamys) bellilarnellatus n. sp ___ ............................. _ . 108 

P. ( Chlamys) hastatns Sowerby .. _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 

P. (Chlamys) hastatus var. hericius Gould (persists from Miocene)... 110 

P. ( Chlamys) hastatus var. hindsii Carpenter. __ • __ ............... _ 111 

P. (Chlamys) hastatus var. navarchus Dall .. _ -~ --.-----.- .. -....... 112 

P. (Chlamys) hastatusvar. strategnsDall ................. ---------- 113 

P. (Chlamys) islandicns Muller ...................... ; . . . . . . . . . ... . 113 
SYNOPSIS OF SUBGENERA .AND SPECIES. 43 

Class PELEOYPODA -Continued. 

Order P RIO NO DESMA CEA,--Continued. 

Superfamily PECTINACEA-Continued. 

Family PECTINIDJE-Continued. 

Genus Pecten Muller-Continued. 

Pliocene Pectens-Continued. Page . 

. P: (Chlamys) jordani Arnold-------------------------------------- 114 

P. (Chlamys) latiauritus Conrad __________________________________ . 115 

P. (Chlamys) lawsoni n. SP---------------------------------------- 117 

P. ( Chlamys) nutteri n. sp. (persists from Miocene)_________________ 69 

P. (Chlamys) o"puntiaDall. _______________________________________ 118 

P. (Chlamys) parmeleeiDall______________________________________ 119 

P. (Chlamys) washburnei n. sp _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 119 

P. ( Chlamys) wattsi n. sp _________________ ______ ........... _ . . . . . . 120 

P. (Chlamys) wattsi var. morani n. var. _____ . ____ .............. ____ 121 

P. (Lyropecten) ashleyi n. SP------·---------··--------------------- 122 

P. (Lyropecten) estrellanus var. catalinffi n. var. (pe:rsists from 

Miocene ) _________ .. ______ . ______________________ . _____ . ____ . 76 

P. (Plagioctenium) cerrosensisGabb _______________________________ 123 

P. (Plagioctenium) circularis Sowerby (?) ____ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 125 

P. ( Plagioctenium) cooperi n. sp ____________________ . __ . _ _ _ _ _ _ _ _ _ _ _ 124 

P. (Pseudamusium) peclroanus Trask (persists from Miocene)_._.____ 90 

P. ( Propeamusium) riversi n. sp ___________________________________ • 126 

P. ( Hinnites) giganteus Gray (persists from Miocene) ______ ~ ___ . _ _ _ _ 93 

Pleistocene Pectens _ . ____ . ______________________________________ . ___ . _ 127 

P. (Pecten) diegensisDall ______________________ , ___________________ 127 

P. (Pecten) vogdesi n. sp. (persists from Pliocene). _____________ .... 100 

P. (Patino pecten) caurinus Gould (persists from Pliocene). ___ .______ 101 

P. ( N odipecten) subnodosus Sower by __________________________ ... _ 128 

P. ( Chlamys) hastatus Sower by (persists from Pliocene) ____ . ____ . _. _ 108 

P. (Chlamys) ha~tatus var. hericius Gould (persists from Miocene) _ _ 110 

P. (Chlamys) hastatus var. hindsii Carpenter (persists from Pliocene) c 111 

P. ( Chlamys) hastatus var. navarchus Dall (persists from Pliocene) _ _ 112 

P. ( Chlamys) hastatus var. strategus Dall (persists from Pliocene)_ .. __ 113 

P. ( Chlamys) islandicus Muller (persists from Pliocene) ______ ._ ___ .__ 113 

P. ( Chlamys) latiauritus Conrad (persists from Pliocene) ______ . _ _ _ _ _ 115 

P. ( Chlan1ys) latiauritus var. cerritensis n. var. _________ . ___ . _ _ _ _ _ _ _ 129 

P. ( Chlamys) latiauritus var. delosi n. var _________________________ . 130 

P. (Chlamys) latiauritus var. fucicolus Dall_________________________ 131 

P. ( Chlamys) latiauritus var. monotimeris Conrad _. __ . _ _ _ _ _ _ _ _ _ _ _ _ _ 131 

P. ( Plagioctenium) cireularis Sower by (persists from Pliocene) _ ~ _ _ _ _ _ 125 

P. ( Plagioctenium) circularis var. &quisulcatus Carpenter.___________ 132 

P. (Propeamusium) alaskensis Dall. "_. _. _ .. _. ______ . _____________ . _ 133 

P. ( Propeam usi urn) ri versi n. sp. (persists from Pliocene) _____ . _ _ _ _ _ _ 126 

P. ( Hinni tes) gigan teus Gray (persists from Miocene) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 93 

Recent Pectens _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 134 

P. (Pecten) diegensis Dall (persists from Pleistocene)________________ 127 

P. (Pecten) excavatusAnton______________________________________ 134 

P. (Patinopecten) caurinus Gould (persists from Pliocene) _ _ _ _ _ _ _ __ _ 101 

P. (Nodipecten) subnodosus Sowerby (persists from Pleistocene)____ 128 

P. (Chlamys) hastatus Sowerby (persists from Pliocene)-------~---- 108 

P. ( Chlamys) hastatus var. albidus Dall n. var ___________ . ___ .. _ _ _ _ _ 136 

P. ( Chlamys) hastatus var. hericius Gould (persistsfrom Miocene) _ _ 110 

P. (Chlamys) hastatus var. hindsiiCarpenter (persistsfromPliocene). 111 

P. (Chlamys) hastatus var. navarchus Dall (persists from Pliocene).. 112 

P. ( Chlamys) hastatus var. strategus Dall (persists from Pliocene) ... _ 113 
44 TERTIARY AND QUATERNARY PECTENS OF CA.LIFORNIA. 

Class PELEOYPODA-Continued. 

Order PRIONODESJfACEA-Continued. 

Superfamily PECTINACEA-Continued. 

Family PECTINID2E-Continued. 

Genus Pecten Muller-Continued. 

Recent Pectens-Continued. 

P. ( Chlamys) islandicus Muller (persists from Pliocene) ..... _._ .. _ .. 

P. ( Chlamys) latiauritus Conrad (persists from Pli~cene) ___________ . 

P. ( Chlamys) latiauritus var. delosi n. var. (persists from Pleistocene). 

P. (Chlamys) latiauritus var. fucicolusDall (persists from Pleistocene). 

P. ( Chlamys) latiauritus var. monotimeris ' Conrad (persists from 

Pleistocene) .. _____ . _ . ___ ... ___ .. __ ..... __ . ___ · ___ .. ____ . - -... 

P. (..Equipecten) palmeri Dall ___________ ·--------------------------

P. ( Plagioctenium) paucicostatus Carpenter ____ ~ . _________ .. __ ..... . 

P. (Plagioctenium) circularis Sowerby (persists froin Pliocene) ..... . 

P. ( Plagioctenium) circularis var. requisulcatus Carpenter (persists 

from Pleistocene) ... __ . ____ . _ ....... _. __ .. _ .. _ .. ___ .. _ . -.... . 

P. (Pseudamusium) davidsoni Dall ... ~ ______ .... ____ ---- :..- ___ .... . 

P. (Pseudamusium) randolphi Dall _______________________________ _ 

P. (Pseudamusium) randolphi var. tillamookensis n. var .. _. _. _ ... _. 

P. (Pseudamusium) vancouverensis "Whiteaves. ___ . _ ....... __ ...... . 

P. (Propeamusium) alaskensis Dall (persists from Pleistocene) ______ _ 

P. (Hinnites) giganteus Gray (persists from Miocene) ... __ . .. __ ...... . 

· Unidentifiable Pectens .. __ .. ____ .. _ . .. ___ .. __ . __ ... __ .. __ ..... -... -.-. 

P. eatilliformis Conrad (Miocene) . _ . _ .. ____ . ___ ................ __ .. . 

P. nevadan us Conrad (Miocene)_ .. _ .. __ ._. ___ ......... _ .... __ .... . 

P. pyxidatus (Recent) . _______ ... ______ . _____ .. _ ... ______ .. _ . - . -- --

P. subcrenatus Carpenter (Recent) ... _ .. _______ . __ . ___ ......... __ .. 

P. townsendi Gould (Recent)~---- ... --- .... --~---------------------- I 

Summnry of the subgenera and species. 

N urn ber of subgenera represented ............ _ . _ ..... _ ...... _ .............. . 

Number of species represented._ .... _ ... __ . _____ ~ _________________ .. _. _ .......... . __ .. · ........ . 

Old species ... _. ____ . _. _ ... ___ .. __ .. _____ .. ____ .. __________________________ .. _ .. _. . 36 

New species .... ___ .. __ .. ~ ______ ~ ____ . ____ . ________ . _____ . _____________ . . . . . . . . .. -40 

Num~l~ ~!r~:Jii;:~~~ ~~~~~~~~~~~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~:: ~ ~ ~ ~ ~ ~:: ~: ~ :·: ~ ~ ~: ~ ~::::: ~: ~: ~ ~ ~ --- -7 

New varieties . __ . ___ . _ .. ____ . _ . __ . _ . ____ . _ . ________ .... _ . ____ .... ________ . _ .. ___ . _ 10 

Number of species included inPecten s. s." ____________ .. ________ : ___ _ ... : ............ _ . _ .. . 

Number of species included in Patinopecten __ . _____ ~ _____ ~ _ . __ . ___ .. __ · __ ... __ ... __ . _. ___ ..... .. 

Number of species included in Nodi pecten .... _ ... _ ..... .. .. .. .... _ ...... : .. __ ... : ............. ___ .. 

Number of species included in Chlamys ................................ _ ..... ~ ... __ ......... _ .. . 

Number of varieties included in Chlamys .. _ .. __ ... ___________ .. _ .... ____ ..... _ ...... _ ....... . 

Number of species included in Lyropecten .. _ ..... _ ... _ .. _________ ...... . _______ .. _ ... ___ . , _____ . 

Number of varieties included in Lyropecten. ___ . _____ .................... _ ......... _ ..... _ .. . 

Number of species included in £qui pecten .. _ .. __ .. ____ ..... . .................. _ ........... . 

Number of species included in Plagioctenium . ______ . ____ . _ ............ _ ........... __ ... _ .. . 

N urn her of varieties included in Plagioctenium .. _ ..... _ ......... _: ............. " ......... ___ . 

Number of species ineluded in Pseudamusium . ____ ............ _. _ ... _. _ ..... _ ....... _. ____ _ 

Number of varieties included in Pseudamusium . ___ . _. _ ................. _ ....... _ ... _.- _---. 

. Number of species included in Amusium ___ .. _________ . ___ .. ___ .. __ ·- _ ............... __ . _. ___ . 

Number of species included in Propeamusium. __ . .. _. ____________ ...................... ___ . 

N urn ber of species included in Hinnites . __ ........ _______ .. _____ . . __ ........ _ ... ________ ... . 

Page. 

113 

115 

130 

131 

131 

136 

137 

125 

132 

138 

138 

139 

140 

133 

93 

141 

141 

141 

141 

142 

142 

11 

76 

17 

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8 

2 

17 

11 

9 

3 

1 

11 

2 

6 

1 

1 

6 

1 
SYNOPSIS AND DESCRIPTIONS OF SUBGENERA AND Sl)EOJES. 

DESCRIPTIONS OF SUBGENERA AND SPECIES. 

Class PELECYPODA. 

Order PRIONODES"'"lfACEA. 

Superfamily PECTIN ACEA. 

Family PECTINIDJE. 

Genus Pecten a Muller. 

1776. Pecten (Klein, 1753) Muller, Prodr. Zool. Dan., p. 248. 

1778. Pecten Da Costa, Brit. Conch., p. 140. 

1798. Pecten Bolten, Mus. Bolt., p. 165. 

1799. Pecten Lamarck, Prodr. d'un Nouv. Class. Coq., p. 88. 

1898. Pecten Dall, Trans. Wagner Free In st. Sci., vol. 3, pt. 4, p. 689. 

Type, Ostrea maxirna Linne. 

GENUS PECTEN. },FULLER. 

45 

"The shell of Pecten comprises two generally more or less discrepant valves, 

united along a long, .straight hinge line by an inconspicuous ligament and a 

central strong resilium. A single rounded adduc.tor leaves its impression pretty 

·P 

FIG. 1.-Pecten circularis Sowerby var. xquisulcatus Carpenter. Right valve, i. e., the valve having the byssal notch; 

exterior. Dimensions: "Altitude" is distance between the base (B) and the apex of the shell or umbo (U); 

"longitudt:" is the distance between the anterior extremity (A) and the posterior extremity (P); "diameter" is 

the maximum perpendicular distance from the plane of the periphery (margin or border) to the top of the arched 

disk, when the shell is lying interior downward; A, anterior end; P, posterior end; B, base; U, umbo; U P B A, 

disk; ae, anterior ear or auricle; pe, posterior ear or auricle; bn, byssal notch or sinus; ba, byssal area; p&, posterior 

sinus; sm, submargins or lateral areas; r, ribs; is, interspaces. 

high up, a little before the mesial line of the valves, and the pedal retractors 

are usually attached to the left valve above it, being often obsolete on the right 

t!ide. The ends of the resilium are received by subtriangular or oval pits in the 

a The generic and subgeneric classification and descriptions, and also the general discussion relating to Pecten, ate 

taken from Doctor Dall's monograph of the genus in "The Tertiary Fauna of Florida," Trans. Wagner Free Inst. Sci., 

vol. 3, pt. 4, 1898, pp. 689-758. In many cases parts of the discussion and descriptions have been copied verbatim. Unless 

otherwise stated, all passages occurring in quotations have been copied from the above monograph. 
4o TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

nmbonal region. TheRe pits may be shallow or deep; their basal margin sometimes 

projects slightly into the cavity of the valves; their apex is always nearly coincident 

with the umbonal point of the valve. · In a few species in the right valve the lateral 

margins of the pit are raised into tooth-like processes, which fit into corresponding 

depressions in the opposite valve (e. g., P. swiftii Bernh.), but these are not 

homologous with the so-called teeth of Plicatula and Spondyl,us. Outside of these, 

radiating fanlike from the apex of the valve, are frequently found one to three 

pairs of more or less prominent laminre, which I call the cardinal crura, and farther 

away and below on the ridges which mark the lower boundary of the ears will 

sometimes be found another pair, only distally conspicuous, which I have named the 

auricular crura. The cardinal crura are most conspicuom; in heavy shells, especially 

such as Pecten proper and Lyropecten, and serve to adjust the closing of the valves, 

as does the hinge armature of the Teleodonts. In a few species the crura are 

A 

B 

FIG. 2.-Same species as fig. 1. Right valve; interior. A; P, B and U as in fig. 1; hl, hinge line; rp, resilial pit; pp, 

provinculum; cc, cc, cardinal crura; bn, bysSI\1 notch; crn, ctenolium; as, adductor scar. 

sufficiently prominent to actually interlock with the valves half open; in many others 

hardly any trace of them is visible. Almost aU species possess in the nepionic stage 

a well-marked provinculum, formed by an elongated area on each side of the pit, 

eovered by long, narrow, close-set taxodont teeth, separated by narrow grooved 

interspaces. In most species the provinculum is evanescent or represented in the 

adult o~ly by faint vertical strire, which cross the cardinal crura. In a few small, 

thin-shelled, mostly deep-water species the provinculum is persistent and functional 

(e. g., P. thalassinum Dall), forming an interlocking hinge~ · In Pecten proper, 

Ohlarnys, and some other groups the upper cardinal margin of the right valve is 

bent over that of the left valve. There are occasional species in which the adult 

valves have each a flat area along the whole cardinal margin, covered by the ligament 

aud forming, a V -shaped groove between the upper margins of the valves, as in .J>. 

swifti,£. The disk of the valve is usually rounded or oblique below and at the sides, 
GENUS PECTEN MULLER. 47 

but above continued on each side in a straight line to the umbo. The shell adjacent 

to these straight lines is frequently slightly different in sculpture from the rest of 

the disk, forming narrow areas, which were called by Conrad the • submargins.' 

Above the submargins the auricles or ears project, usualiy differentiated by a linear 

depression ending in a sinus below. This sinus is sometimes absent in the posterior 

ears, as it is in the very young stages of the shell, but it is not an important 

systematic character, since the same species (e. g., P. lat,iauritus Conr.) may exhibit 

varieties some of which have a well-developed posterior sinus while others are without 

it. The right anterior sinus is_ usually emphasized by a fiexuosity in the lower edge 

of the ear above it for the accommodation of the byssus, and on the upper part of 

submargin are usually found a number of small, regularly spaced spines, which in 

life separate the threads of the byssus and thus keep it from twisting with the motion 

of the water. The growth of the margin of the valve and ear does not always march 

with the development of these spines, so that a species which normally has them may 

exhibit stages when the valve margin has grown over the old set and the new set bas 

not been form~d, much like the inequalities of growth shown by the margin of the 

aperture and the internallirre of some Gasteropods. This set of spines, resembling a 

short comb with curved teeth, has been called ctenolium, pectineum, and pectinidium. 

In old very heavy shells, which are held in place more by their own weight than by 

the formation of a byssus, they are often absent, but may usually be traced in the 

groove corresponding to the younger stages or fasciole of the sinus." 

The . shell of Pecten, being thin . in proportion to its surface, is in the adult 

usually ribbed or fluted. This condition is brought about, doubtless, by natural 

selectiori, and serves to strengthen the valves which, in swimming and falling to the 

bottom, are often subjected to rude shocks. Shelly matter is sometimes deposited 

internally in the shape of radiating line to still further strengthen the disk. 

In addition to the ribs and riblets, the surface of Pecten may be ornamented by 

fine, almost microscopic groovings, which radiate from the umbo (shown in P. 

peckham,i), or by a minute concentric sculpture due to imbricated incremental lines. 

A combination of minute concentric and radial sculpture often gives the surface, 

especially in Ohiamys, a checkered squamation or microscopic reticulation. 

"The original prototype of Pecten, judging fi'om the stages of recent shells 

and the succession of the fossils, was a thin, nearly smooth shell, with a taxodont 

provinculum and the posterior ears ill-defined." These characteristics. have been 

altered in the subsequent forms to meet conditions of environment, in some 

instances certain features appearing and then becoming obsolete as their usefulness 

decreased. 

"The discrepancy in size of the valves appears to be more or less related to 

the activity of the animal; the species in which the difference is greatest being 

probably the more sedentary." 

P. exc(Jfl)atus is an: example of a species in which the discrepancy is very 

great, the right valve being extremely convex, while the left is somewhat concave. 

Where a discrepancy is shown the right is usually the more convex valve, although 

in some instances, notably in P. bowersi and P. andersoni, the reverse is true. 

The swiJ!lming habit is often ex~rcised by Pecten, it b~ing more common to 

the thin-shelled, light, and young in,9.ividual than to the thick-shelled, adult, and 
• 

48 TERTiARY .AND QUATERNARY PECTENS OF CALIFORNIA. 

sedentary forms. The movement, although quite rapid, is jerky, and is produced 

by the expulsion of water through the cavity of the auricles; the ventrai margins 

of the valves being in advance as the animal moves. 

'" In various geological horizons, as well as in the existing fauna, certain species 

of l)ecten assume a sessile habit, involving an irregular subsequent growth of the 

valves after attachment to other objects, as in Hinnites. These species have no necessary genetic connection with one another except what they gain from their relations to the Pectinidm as a group, and must be regarded as purely sporadic adjustments of individual forms to a particular environment.'' 

''The influence of the environment is very marked among the Pectens. As in 

mammals and birds, the same species in the northern part of its range is larger than 

in the south, unless it is a distinctively tropical species. . But in color the rule is 

reversed, the southern species being lighter and more brightly tinted than the northern ones in the same species. The specimens which live in deep water and swim 

actively are usually thinner shelled and smoother, while those which inhabit the 

lagoons are heavier, have more conspicuous concentric sculpture and more solid 

shells." 

The Pectens seem to form a natural genus which may be separated for convenience into groups, but as might be expected when the fossil forms are taken 

into consideration, these groups merge into one another by insensible gradations. 

Whatever might be advisable were our knowledge of the Pectin·idm confined to 

the recent species, any paleontological division of them can not ignore the intergradation which is so obvious between the different types of which the extremes 

appear so unlike. 

The subdivisions adopted l;lere, although more . or less widely separated in 

the California fauna, are known elsewhere t.o be connected by intimate gradations. 

For that reason they are assigned to a rank compatible with ·such relations. As 

would be expected, the relative importance attached to the characteristics upon 

which groups are founded is regulated more or less by the personal equation; 

therefore, in order to avoid the complications often arising from a too close 

discrimination, it has been deemed advisable in this paper to make all of the 

subdivisions which are worthy of a group name bear the grade of subgenus. 

The following groups of Pecten are represented in the Tertiary and living 

fauna of C~lifornia: 

Subgenus Pecten s. s. Muller. 

Type P. maxin1us Linne. ~ 

Right valve moderately inflated, left valve flattish; sculpture of strong ribs 

with radial striation, more or less roughened by simple concentric lamellation or 

incremental sculpture; ears subequal. · 

This group includes the following Pectens: auburyi, bellus, ca1·rizoensis, 

coalingaensis, diegensis, excavatus, hemphilli, · keepi, lecontei, merriami, sanctmcruzensis, stearnsii, and vogde8i. 

Subgenus Patinopecten Dall, 1898. 

Type P. caurinus Gould. 

Valves with small ribs, flat on the right valve, and sometimes dichotomous; 
GENUS PECTEN MULLER. 

smaller and more rounded on the left valve; concentric sculptur~ incon~picuous; 

radial strire ab:::~ent or obsolete, ears subequal; valves nearly equilateral. 

To this group belong the following Pectens: coosensis, caurinus, dilleri, 

healeyi, orweni, puTishnaensis, propat~tl~ts, and turneri. 

Subgenus Nodipecten Dall, 1898. 

Type P. nodosus Linne. 

Shell like Lyropecten, but the ribs intermittently nodose, with more or less 

prominent hollow nodes or bullre; radial striation pronounced; ears unequal, the 

posterior smaller, the valves often more or less oblique; imbricate surface layer 

sometimes very marked. (P. rwattsi is a connecting link between this subgenus 

and the typical Chlamys.) 

The only representatives of this group are 1). subnodosus and P. veatchii. 

Subgenus Chlamys Bolten, 1798. 

Type 1). islandicus M iiller. 

Valves moderately inflated, subequal, similar, oplique, or with unequal ears, 

the posterior sma1ler; Oamptonectes striation and imbricate surface layer usually 

present; shell usually solid and opaque; byssal notch and ctenolium present. 

Under this subgenus are grouped the following Pectens: bartschi, bellilamellatus, branneri, calkinsi, fucan~ts, lwmlini, hastatus and vars. erici~tS , albidu8, 

k -/ndsii, navarchus and strategus, islandicus, jordani, landesi, latiauritus and vars. 

cerriten.~is, delosi, fucicolus and monotimeris, za,wsoni, nutter'l:, opuntia, parmeleei, 

proavus, sespeensis, and its variety h,ydel:, washb~trnei, rwattsi, and its variety morani. 

Subgenus Lyropecten Conrad, 18~2. 

Type P. estrellanus Conrad. 

Shell resembling I)ecten s. s., but with both valves convex; usually of large 

size, heavy, and with radial striation and minute concentric imbrication; ribs entire, 

and not dichotomous; valves equilateral and sometimes more or less undulated in 

the vicinity of the urn bones. , 

This group includes the following Pectens: Ashleyi, borwersi, crassicardo and 

its variety hamiltoni, estrellanus and its varieties catalinm and term,in,us, magnolia, 

miguelensis, perrini, and vaughani. 

Subgenus ~quipecten Fischer, 1887. 

Type 1). opercularis Linne. 

Shell thin, orbicular, with subequal inflated valves, usually equilateral, with 

uniform, well-marked radial, not dichotomous, ribs and finely imbricate -radial 

striation; , ears subequal; valves internally lirate on the edges of the grooves 

corresponding to the external ribs; Oamptonectes striation present, but usually 

obscured by the radial sculpture; ctenolium and byssal notch obvious. 

The single representative of this group is P. palmeri. 

17260--~o. 47--06----4 
50 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

Subgenus Plagioctenium Dall, 1898. 

Type P. circularis Sowerby. 

Resembling .Ai:quipecten but without radial striation; the cone.entric sculpture 

in looped lamellre; the ribs strong, frequently smooth above; the submargins 

impressed below the subequal auricles; the valves well inflated with a tendency 

to oblique growth in the adult. 

This group includes the following species of Pecten: Andersorn//, ander'8oni 

var. barkerianus, cerro8ensi8 and its variety rnendenhalli, circularis and its variety 

cequisnlcatus, cooperi, dismtS, deserti, eldridgei, neahensis, pabloensi8, pa·ucicostatus. 

Subgenus Pseudamusium H. and A. Adams, 1858. 

· Type P. ewoticus Chemnitz = P. pseudarnus·iurn (Klein) Sowerby. 

Shells small, thin, more or less translucent; inner face of the disk without 

lirre; sculpture discrepant on the two valves, the right valve having the concentric 

and the left valve the radial elements most pronounced; valves usually flattish 

or compressed. , 

The following Pectens are placed in this group: Davidsoni, lompicoensis, peck: 

harni, pedroan·us, randolphi arid its variety tillamooken8is, and vancouverensis. 

Subgenus Amusium Bolten, 1798. 

Type P. pleuronectes Linne. 

Valves flattish, internally lirate, externally usually smooth or faintly striated, 

both valves being similarly sculptured; the ctenolium absent and . the byssal notch 

obsolete. · 

This group is represented by the single species P. lom:pocensis. 

Subgenus Propean{usium Gregorio, 1883. 

Type P. 'ineqttisculptus Tiberi (=P. fenestratus Forbes). 

Right valve impressed about the distal margin, which is not fully calcified, 

partially concave, the sides partially closed away from the ears; the internal lirre 

present but shorter; the1 external sculptp.re chiefly concentric, while on the left 

valve, if present, it is radial; the recent forms usually glassy or pale colored in 

. both valves. · · 

In this group are included the following Pectens: Alaskensis, clallarnensis, 

interradiatus, rvversz, stanfor·densis, and waylandi. 

Subgenus Hinnites Defrance, 1821. 

Type H. cortezi Defrance. 

Shell (up to advanced youth) a typical Chlarnys, later becoming sessile and 

irregular, in which stage the resilial pit is elongated and cardinal margin· 

develops an obscure area. 

This group is represented by the single species J>ecten giganteus. 
DESCRIPTIONS OF SUBGENERA AND SPECIES. 51 

EOCENE PECTENS. 

[Those known first to appear in the Eocene formations.] 

PECTEN (CHLAMYS) CALKINS! n. sp. 

Pl. II, figs. 1 and 2. 

Descript,ion.-Shell averaging about 35 millimeters in altitude, subcircular, 

equivalve or nearly so, equilateral, rather thin,. somewhat ventricose, and with only 

slightly serrate margins. Right valve with the exterior surface ornamented by 

about '05 small, squarish, ~lightly imbricated ribs, which show a tendency to ·become 

dichotomous near the end in some specimens; interspaces channeled and about . 

one-half as ,wide as the ribs; hinge line about three-fifths the length of the disk; 

ears equal in length, flat and with the swell of the disk commencing at right · 

angles to · them; anterior ear sculptured by 4 or 5 imbricated radiating ridges; 

byssal notch di8tinct; posteriot! ear sculptured in a similar manner to the anterior. 

Left valve similar to the right except that in the former the ribs are slightly 

more rounded and the anterior ear has no notch. 

Dim,ensions.--Alt. 30 mm.; long. 31 _mm.; hinge line 18 mm.; diameter 6 mm. 

So far as known this species has no closely allied forms in any of the other 

California Tertiary formations, and for that reason is admirable as a diagnostic 

form for the Tejon. The type and several other specimens of this species were 

among some material collected by Dr. H. W. Fairbanks on the north side of the 

Si8ar -V fllley ~ north of the Astarte oil wells, Ventura County. At this locality it 

was associated with . the following characteristic Tejon fauna: Area sp., Cardium 

breweri, Meretrix horni, .Jlfo diol~ts ornatus, Tapes sp., Turritella ~tvascma, Venericardia planicosta Lam. var. hornii. 

The types of P. calkinsi are now in the collection of the University of 

California. Named in honor of lVIr. Frank C. Calkins, of the United States · 

Geological Survey. 

RANGE. 

Eocene (Tejon). Sisar Valley, Ventura County (Fairbanks). 

PECTEN (CHLAMYS) LANDES! n. sp. 

Pl. II, figs. 3, 4, and 5. 

Description.-Shell averaging about 34 millimeters in altitude, about as long 

as high, subcircular, inequivalve, equilateral, thin, slightly ventricose~ and with 

serrate margins. · Right valve more ventricose than left, and flattening toward 

the periphery in the adult; surface ornamented by fro'm 25 to 40 subequal, 

rounded, more or less i_mbricate ribs, separated from each other by subequal, 

eoncave-bottomed interspaces, which average about as wide as the ribs; hinge line 

slightly longer than one-half length of disk; ears somewhat unequal, the anterior 

being slightly the longer: anterior ear sculptured by 4 prominent radials, while 

the posterior has from 6 to 8 less prominent ones; byssal notch deep; whole 

surface of disk and ears crossed by numerous fine imbricating lamelhe. · Left 
52 i 

TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

valve more compressed than rjght, similarly sculptured, but with both ears 

slightly obliquely truncated, the anterior one showing a broad shallow notch. 

Hinge and muscle scars similar to P. islandicus. 

I 

D imensions.-Alt. 34 mm.; long. 33.5 mm.; hinge line 19 mm.; diameter 12 

mm. (right valve 7 mm., left valve 5 mm. ). 

The general outline and convexity of all the shells of this species appear to 

be about the same, but the ribs are quite vari~ble, as regards both number and 

shape. In most cases the ribs are evenly rounded and about equal in width to 

the interspaces, but in some cases they are ridgelike and narrower than the 

interspaces. In some specimens a few of the ribs become dichotomous distant 10 

or 15 millimeters from the umbo, and small riblets are intercalated in a few of 

the interspaces at about the same distance. One specimen i8 contracted at a · distance of about 30 millimeters', and shows several ·intercalaries beyond the line 

of contraction. Some of the specimens of P. landesi remind one somewhat of 

P. rn mbr nos~ts Morton, from the Eocene of North Carolina, although the latter 

has more and narrower ribs, and · is ornamented by finer imbricating sculpture 

than the former. P. landesi is distinguishable from P. proavus by its relatively 

longer disk and fewer but more prominent, regular, and less imbricated ribs. It 

. is distinguishable from P. calkinsi by its smaller size when adult, fewer but 

more elevated ribs, and relatively much shorter hinge line. 

P. landesi is found quite abundantly in a dark-greenish sandstone bed that 

outcrops about 100 yards west of the junction of Stillwater and Olequa creeks 

(U. S. Nat. Mus. locality 4019) one-fourth mile · southwest of Little .Falls, Lewis 

County, Wash. It is also found in a similar matrix in the bed of Olequa Creek 

(U. S. Nat. Mus. 4024), 1 mile north of the first locality. It -is associated in this 

· formation with a characteristic Eocene fauna, among which are the following 

species: Venericard1.:a planicosta Lamarck, Thracia dilleri Dall, Orassat~llit 8 sp., 

Meretri x sp., Ostrea sp., Pterz'a (cf.) limula Con~ad, Cardium 2 sp., Barbatia sp., 

.Glyqpneris sp., Corbula .sp., Oallista sp., Turritella (c£.) uvasana Conrad, Fusus 

4 sp., Ocinebra sp., Ranella sp., Calyptroplwrus sp., Lunatia sp., Turbinella (?) sp., 

.Murex 2 sp., Comus sp., Cassis sp., Tritonium sp., Dentaliurn ( cf.) cooperi Gabb, and 

Nautilus sp. This horizon is probably upper Eocene, possibly above the Tejon. 

Named in honor of Pro£. Henry Landes, Seattle, Wash. 

RANGE. 

Eocene (probably upper). Vicinity of Little Falls, Lewis County, " rash. U. S. 

Nat. Mus. locality 4019; 4024. (Arnold.) 

PECTEN (CHLAMYS) PROAVUS n. sp. 

Pl. II, figs. 6, 7, and 8. 

Description.-Shell averaging about 50 millimeters in altitude, much higher 

than long, compressed, subequivalve, and equilateral, except for the ears; base 

regularly rounded; margins s~ooth; sides straight and forming an acute angle at 

the umbo. Left 'valve with numerous more or less unequal, narrow, thread-like, · 

imbricated ribs, between which are occasionally much finer ihtercalaries; interspaces 

about as wide as ribs, channeled and flat bottomed; whole surface of disk and 

• 
EOCENE PECTENS. 53 

ears ornamented by numerous, sharp, imbricating lamellrn of growth, which appear 

more prominently on the anterior portion of the disk; posterior ear short, slightly 

obliquely truncated, and sculptured by numerous radials and imbricating lamellrn; 

anterior ear unknown, but probably much longer than · posterior. 

DZ:mension._'<. -Alt. 38 mm.; long. 30 mm.; hinge line (restored and approximate) 

18 mm.; diameter 7 mm. 

This species is closely allied to P. traski Gabb, from the Cretaceous of the 

Pacific coast. It differs from the latter, however, in not having the diagonal 

microscropic sculpture so characteristic of that species. 

A fragment of a much larger specimen than the type of P. proavus, from the 

same beds and probably the same species, shows, near the periphery, narrow 

ridge-like ribs separated by rather wide interspaces in each of which are two o.r 

three fine thread-like riblets. (Pl. II, fig. 8.) 

The type of P. proavus, which is now in the collection of the department 

of geology, Stanford 'University, is a poorly preserved cast of a left valve 

on which part of the original shell matter is still preserved. It came from 

beds of probable lower Eocene (Martinez) age in the ridge between the 

headwaters of Pescadero Creek and San Lorenzo River, San Mateo County. 

At this locality it was associated with the following fauna: Terebratulina tejonen8is, 

Tritom:ttm (cf.) californicum,, Patella (ct) traski, Helcion diclwtoma, Ostrea (aff.-) 

idriaensis, Turbo sp., Acmcea or Patella sp., Terebrcdttla n. sp., G1'daris (?)spines 

Semele sp. After an examination of the above fauna Doctor Stanton was of the· 

opinion that it was younger than the Chico (Cretaceous). It is certainly not 

typical Tejon (middle or upper Eocene), but appears to be closer to the Martinez 

fauna than to any other, and is, therefore, tentatively placed in the horizon of the 

latter. RANGE. 

Lower Eocene (Martinez?). Between the headwaters of Pescadero Creek and the 

San Lorenzo River, San Mateo County (H. S. Gay; Arnold). 

PECTEN (PROPEAMUSIUM) INTERRADIATUS GABB. 

Pl. II, figs. 9, 10, and 11. 

1869. Pecten interradiatus Gabb, Pal. Cal., vol. 2, 1869, pp. 199-200, pL 33, :figs. 98, 98a. 

1888. Pecten interradiatus Gabb, Cooper, Seventh Ann. Rept. CaL St. Min., 1887, p. 289. (From 

"Cretaceous B," which is Eocene). 

Description.-" Shell small, subcircular, equivalve, equilateral, compresse_d, thin; 

upper [left] valve, ears equal, moderately large; lower [right]valve, right ear long, 

deeply and narrowly emarginate. Surface marked by very numerous fine radiating 

lines, and obscure lines of growth. Internal surface of both valves bearing 8 

straight, equidistant, large ribs of variable length among themselves, extending 

from the beaks to near the middle of the shell and ending abruptly." 

.Dimensions.-Alt. 25 mm.; long. 24 mm.; hinge line 15 mm.; diameter 2.5 mm. 

This species may be distinguished · from P. stanforderusis by its larger size, 

narrower anterior ear of right valve, and fewer number of interior ribs. , It is. also . 

distinguishable from P. clallamensis and P. waylandi by its larger size and inconspicuous ,external surface sculpture. 
54 TERTIARY AND QUATERNARY PEO'l'ENS OF CALIFORNIA. 

Gabb states that the type of P. interradiatu8 is from the ''buff-colored shale 

east of New Idria, at or near the summit of the Tejon Group" [Eocene], where he 

found it very abundant. Two spec.imens from the collection of the University of 

California, which were collected by Mr. H. W. Turner at New· Idria, are in a hard, 

dark-colored shale. 

A Pecten allied to P. interradiatu8, accompanied by the following note, was 

sent .to the writer by Dr. J. C. Merriam, of Berkeley: " .Road cutting below 

Profe.ssor Richer's house at mouth of Strawberry Canyon, Berkeley. Cutting now 

walled up. A. C. L. Cretaceous shale." This species, which is represented by an 

internal cast, is 12 millimeters in altitude, 10 millimeters in longitude, and has a hinge 

line 3.5 millimeters in length. It has io prominent rounded internal ribs e:x:tending 

f'rom the umbo nearly to the periphery, and in several of the broad interspaces a 

rounded intercalary, whieh begins at a distance of about 7.5 millimeters from the 

umbo and extends nearly to the periphery . . The anterior ear of the shell (which is 

a right valve) is slightly longer than the posterior, arcuate in front, and has but a 

faint suggestion of a byssal notch. 

The figures of P. interradiatu8, which are natural size, are copied from the 

originals of the type in Pal. Cal., vol. 2, pl. 33, figs·. 98, 98a~ 

RANGE. 

Eocene (?pper Tejon). New Idria, San Benito County (Gabb; Turner). 

OLIGOCENE PECTENS. 

(rhose known first to appear in the Oligocene formations.] 

PECTEN (PECTEN) SANCT1ECRUZENSIS n. sp. 

Pl. III, figR. 12 and 13. 

1903. Pecten (Pecten) twobarensis Arnold, MS. 

D escr{ption.-Shell averaging about 50 millimeters in altitude, slightly longer 

than high, plano-convex, equilateral, rather thin; base regularly rounded; sid.es 

only slightly concave above; margins smooth. 'Right valve quite convex ~nd 

ornamented with about 12 prominent, perpendic~lar-sided, slightly convex-topped 

ribs, separated by :flat-bottomed, channeled interspaces about equal in width to the 

ribs; surface sculptured by small, almost imperceptible, obsolete, radiating striations 

and numerous fine sharp concentric lines; hinge line considerably longer than one 

h11lf length of disk; ears subequal; anterior with shallow byssal notch and fine, 

sharp concentric lines; posterior similarly sculptured, but rectangularly truncated. 

Left valve :flat, with slight concavity near umbo; lateral areas rather prominent; 

ribs squarish, with slightly convex tops narrower than those of the right v:ahre 

and with proportionally wider interpaces; ears subequal, rectangularly truncated, 

and · with surface sculptured by numerous fine, sharp incremental lines. 

Dimen8ion8.-Alt. 52 mm.; long. 55 mm. ;· hinge line 32 mm.; diameter about 

l3 mm.; unbonal angle 110° . 

This species is allied to P. bellU8 and may be its precursor, as it Is· very 

similar to the latter in most respects. P. 8anctmcruzen8is may be distinguished 

' 
OLIGOCENE PECTENS. 55 

from I>. bellus by its fewer ribs (11 instead of 14) and relatively smaller size 

when adult. 

P. sanctcecruzensi8 is so far known only from beds which appear to be transitional from the Oligocene to the lower lVlioeene. At locality No. 111 (L. S. J. U. 

Geol. Survey) on Twobar Creek, one-fourth mile above its junction with San 

Lorenzo River, Santa Cruz County, the type .was found associated in a soft sandstone with the following speeies: Pecten branneri n. sp., Oyth.era (cf.) vespertina, 

Tritonittm sp. No. 1, Oorbttla (n sp., Yoldia (cf.) irnJJ'l'essa,. Nucula n. sp. (large, 

with coarse sculpture), L eda sp. B. and C., Oidaris (?) spines, Oallista sp., Tellina 

(Angttlus) sp., Cardium n. sp., near cooperi, Teredo sp., Chione (cf.) mathewsoni. 

One mile southeast of Cowell's asphaltum quarry (locality 30), near Santa Cruz, 

P. sanctcecruzensis is associated with P. pecklwmi, Nuc-ula sp., Phacoides sp., and 

Chione· sp. 

The type, a beautifully preserved mold of a left valve, is now in the ~ollection 

of the department of geology, Stanford University. A small cobblestone containing two right and two left valves of P. sanctcecruzensis was found by Miss 

L. J. F. Hecox, of Santa Cruz, as float in Bear Creek, about 2 miles from the 

type locality. One of these right valves is figured and serves as a co type. 

RANGE. 

Oligocene:-Miocene. Twobar Creek and Bear Creek, Santa Cruz County (Arnold; 

Hecox)~ 

PECTEN (CHLAMYS) BRANNER! n. sp. 

Pl. III, figs. 9, 10, and 11. 

D escription.-Adult shell averaging about 80 millimeters in altitude, higher 

than long, · equivalve, slightly convex, and equilateral, except for ears; sides only 

slightly concave above; base regularly rounded below. Right valve with from 20 

to 22 prominent, narrow, more or less s~aly or spiny ribs, which in the adults 

are sometimes medially ~mlcated or dichotomous; . interspaces generally much 

broader than the ribs, channeled and usually containing a spiny or scaly intercalary rib; whole surface sculptured by imbricating incremental lines, often also 

by microscopic. reticulations; hinge line about two-thirds length of disk; anterior 

ear much produced and sculptured by 6 to 10 imbricated ridges, which are separated 

by equally wide reticulated interspaces; byssal notch profound; posterior ear 

about three-fifths length of anterior, and sculptured similarly. Left valve similar 

to right. 

Dimensions.-Alt. 65 mm. ~ long·. 58 mm.; hinge line 40 mm.; diameter 14 

mill.; urn bonal angle 83° . 

Thi~ species ;varies considerably in the degree of impoitance of the minor 

sculpture, such as reticulation, imbrication, and size of the sulcations and 

intercalaries. Although unquestionably allied to the Ohlamys group, it has larger 

posterior ears than other species of the group that have come under the writer's 

notice. P. branneri resembles P. islandicus in size, outline, and general sculpture, 

but is distinguishable by having only about one-half as many ribs and much larger 

posterior ears. 
56 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

So far as is known, P. branneri is confined to the lowest horizon of the 

Miocene and top of the Oligocene. It is very abundant at the type loeality, 

Tuff Hill, near Stanford University. One large right valve was also obtained 

from the fine sandstone immediately overlying the San Lorenzo shale series 

(Oligocene) in Twobar Creek, near the town of Boulder Creek, Santa Cruz 

County. 

The type, like all of the known · speeimens . of the species, is a mold, and is 

now in the collection of the department . of . geology, Leland _Stanford Junior 

University. Named in honor of Dr. J. C. Branner, professor of geology in that 

institution. RANGE. 

Mioeene (lower). Tuff Hill, Stanford · University, Santa Clara County (Branne.r; 

J. P. Smith; Arnold).· 

Oligocene (upper) or Miocene (lower). Twobar Creek, near Boulder Creek, Santa 

Cruz County (Newson; Arnold). 

PECTEN (PsEUDAMusruM) PECKHAM! Gabb. 

Pl. III, figs. 6, 7, and 8. 

1869. Pecten peckhami Gabb, Pal. Cal., vol. 2, 1869, pp. 59, 60, pl. 16, figs. 19 and 19a. 

1888. Pecten peckhami Gabb, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 258. 

1898. Pecten peckhami Gabb, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 705. 

Description.-Shell averaging about 20 millimeters in altitude, subcircular, sub-:-

equivalve, slightly inequilateral, thin, usually compressed, and with smooth margins. 

Right valve with the disk showing several small, more or less obsolete, irregular 

concentric undulations, numerous fine .incremental lines and numerous fine obsolete 

radiating lines; hinge line about two-thirds of th~ longitude of the disk; anterior 

ear produced, separated from the body of the shell by a marked groove and a deep, 

narrow sinus, and prominently seulptured by 6 or 7 radiating ridges and numerous 

coneentrie elevated incremental lines; posterior ear not separated by any distinct line 

from the disk surface and ornamented only by concentric lines and ,obsolete undulations. Left valve similar to 'right except that the anterior ear is flat, the swell of 

the shell commencing with nearly a right angle with the ear surface; surface of 

anterior ear usually sculptured only by incremental lines, but occasionally with 

radiating strire also. -

Dimensions.-Alt. 21 mm.; long. 21 mm.; hinge line 14 mm.; diameter 2 mm. 

As a rule only the molds or casts of this species are found-in the shah~s in which 

they oecur, and for this reason some of the characteristics of sculpture of the species 

are generally lacking. For example, in a large series of specimens examined, only 

two or three of the shells showed the radiating sculpture. The disks are generally 

obliquely distorted and often compressed, but the sculpture on the anterior ear of 

th~ right valve is almost always present and is quite characteristic. 

In California this species is found from the San Lorenzo formation (Oligocene) 

to the Monterey or middle Miocene. P. pecklwmi is found abunclantly in . the 

Monterey shale in N~well Creek canyon, 2 miles above Ben Lomond, Santa Cruz 

County, where it is associated with Area monterey ana Osmont, Corbula sp., Cyth-
OLIGOCENE PECTENS. 57 

erea sp., Diplodonta n. sp., Venericardia ( n n. sp., Leda 2 n. sp., Phacoides sp., 

Semele n. sp., and Tellina c£. congesta Conrad. 

P. p ecklwmi is also abundant in certain horizons of the Oligocene-Miocene of 

Washington, and Mr. Diller has found it in some shales in Oregon. It occurs 

n~ar the base of the Oligocene-Miocene section between Bean and Restoration 

points, west of Seattle, King County, Wash., associated with 0 lypeaster ( ?) sp., 

Terebratula sp., and Teredo sp. At Freshwater Bay, Clallam County, Wash., it 

is found with Doli urn petrosurn Conrad, Fusus sp., Natica or Ltttnatia sp., Nucttla 

cf. decisa Conr., Volutilithes n. sp., Dentalium 8ubstriatmn Conrad, Phacoides 

acttttilineat·us Conrad, Solemya sp., Leda sp., and 11/arginella or Erato sp. Farther 

west along the Strait of Juan de Fuca, 1t miles east of Gettysburg, Clallam 

County, Wash., P. peckhami is associated with Nucula sp., Leda n. sp., .Dentalitt-m 

Stlbstriatum Conrad, Natica sp., etc. One of the specimens of P. peckhami 

from near Bean Point, Washington, shows the anterior ear of the left valve to be 

ornamented by about 13 fine elevated radiating lines. Owing to the comparatively 

good state of preservation of the Washington specimens, nearly all of them show 

the minute concentric and radiating sculpture of the disk and ears in addition to 

the characteristic undulations of the former. 

RANGE. 

Miocene (middle). San Pablo, Contra Costa County (Gabb); southeast of Pinole, 

Contra Costa County (Lawson); Langley Hill, Alpine district, and south of 

Portola., San Mateo County; Felton and Ben Lomond, _Santa Cruz County 

(Smith, Newsom, Arnold); Carmelo Valley, Monterey County (Lawson, 

Turner); Templeton, San Luis Obispo County (Fairbanks, F. M. Anderson); 

northwest of Tulare Lake, Tulare County (Watts); Ojai ranch, Ventura County 

(type locality) (S. F. Peckham); Big Panoche Creek, Fresno County (Turner); 

4 miles south of McKittrick, Kern County (Eldridge). 

Oligocene-Miocene. Ridge west of the headwaters of Boulder Creek and western 

slope of 'the south end of Ben Lomond Mountain, Santa Cruz County (Newsom, 

Arnold). In Washington at localities 4112a and 4113, between Bean and 

Restoration points, King County; locality 4121, Freshwater Bay; location 4120, 

2 miles west of Port Crescent; locality 4114, l~ miles east of Gettysburg, 

Clallam County (Arnold). 

PECTEN (PROPEAMUSIUM) CLALLAl\fENSIS n. sp. 

Pl. III, figs. 1, 2, 3, and 3a. 

Desm·?jJtion.-Adult shell averaging about 10 millimeters in altitude, subcircular, equivalve, equilateral, thin, compressed, and with smooth margins. Right 

valve ornamented externally by numerous equally elevated, sharp, s'lightly imbricate, 

concentric lamellre, separated by equal interspaces, each of which is about five times 

as wide as the thickness of a lamella; hinge line somewhat longer than one-half 

length of disk; ears decidedly unequal, the anterior being about twice as long as the 

posterior; anterior ear arcuate in front and sculptured by numerous regular, sharp, 

elevated, concentric l~mellre and · 5 or 6 slightly elevated, unequally spaced radials; 
58 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

byssal notch not profound; posterior ear rectangularly truncated and ornamented 

with concentric sculpture similar to that of the anterior; interior of disk 

strengthened by nine strong, rounded, elevated, radiating ribs, which terminate 

abruptly at a length of 6 or 7 millimet~rs; the middle ribs are straight, but 

occasionally the lateral ones are faintly arcuate toward the middle rib. Left valve 

beautifully ornamented externally by numerous regular, thin, concentric, imbricating, 

prominently elevated lamellre which, sloping at an angle of about 45° t.oward the 

umbo, rise into 10 or 11 prominent, rounded; radiating pseudo-ribs, separated by 

somewhat wider interspaces, in nearly every one of which is an intercalated, 

imbricated pseudo-riblet; this riblet hegins only after the shell has attained a height 

of about 1.5 to 2 millimeters; ears similarly sculptured to those of the 'right valve. 

Dimensions.-Alt. (type, left valve) 10 mm.; long. 9.5 mm.; hinge line 5.5 mm.; 

diameter about 0. 75 mm. 

This beautiful little Pecten appears to be allied to P. stanfordensis, but · is 

easily distinguished from the latter by its beautifully lamellated surface, and in 

possessing 9 instead of 10 or more internal riblets. . 

The type of P. clallamensis is a left valve (U. S. N. M. No. 164922) and was 

found at locality 4100, 1t mileR east of Pillar Point, near the mouth of the Pysht 

River, Clallam County, Wash., where it was assoqi~ted with Aturia cf. ziczac 

Sower by, .Dolium petrosum Conrad, Fusus sp., Natica or Lunatia, Marginella or 

Erato sp., Nucula sp., Leda sp. (large, smooth), Tell?,"na (Angulus) sp., Solemya sp., 

.Dentalium substriatum Conrad. The cotype is a right valve (U. S. N. M. No. 

164923), is from locality 4070, Bean Point, King County, Wash., and is associated 

there with Terebratula sp., Turritella sp., Marg,inella or Erato sp., Natica or 

Lunatia sp., Glycymeris. sp., and Astyr1:s sp. 

Both of the localities at which P. clallamensis have so far been . found are in 

the lower portion of the Oligocene-Miocene series. 

RANGE. 

Oligocene-Miocene. Mouth of Pysht Rive:r, Clallam County, and Bean Point, west 

of Seattle, . Ktng County, V\7 ash. (Araold). 

PECTEN (PROPEAM;USIUM) WAYLAND! n. sp. 

Pl. III, figs. 4 and 5 . 

.Description.-Adult shell averaging about 9.5 millimeters in altitude, somewhat 

longer than high, subcircular, equivalve, equilateral, thin, somewhat convex in 

youth, but becoming more compressed with age; margins smooth. Disk of right 

valve sculptured by numerous fine lines of growth and numerous, more or less 

obsolete, fine radiating lines; hinge line equal to about one-half the length of the 

disk; ears subequal; ·anterior arcuate in front and faintly sculptured concentrically 

by sharp lines and radially by faint ridges; byssal notch narrow and shallow; 

posterior ear slightly obliquely truncated and sculptured by faint radial ridges 

and fine, sharp, concentric lines; interior of disk strengthened by 8 subequal, 

strong, narrow, smooth, convex-topped riblets, which are widely separated and 

'which -terminate abruptly at about 6 to 8 millimeters from the umbo; these 
MIOCENE PECTENS. 5~ 

internal riblets are usually straight, but the ones distant from the center are often 

slightly arcuate toward the center. Left valve, up to an altitude of 6 or 8 millimeters, ornamented by 8 more or less prominently elevated, narrow, convex-topped 

radiating ridges, corresponding with the same number of equally long, smooth, 

convex-topped internal riblets; whole surface of disk sculptured by numerous 

subequal, inequidistant, sharp, radiating lines (usually varyi!lg from 5 to 7 between 

each major ridge) and faint incremental lines, the latter becoming prominent as 

the radiating ridges become obsolete; ears similar to those of right valve, with 

the exception that there is no byssal notch in the anterior one. 

Dimensions.-Alt. 9.5 mm.; long. 12 mm.; hinge line 5.5 mm.; diameter 

about 0. 75 mm. 

This little Pecten is closely allied to ]>. stanfordensis, but may be distinguished 

from the latter by the more prominently elevated ridges on the left valve, the 

greater prominence of its microscopic radial sculpture, and the smaller number 

(8 instead of 10 to 12) of internal riblets. P. waylandi is distinguishable from P. 

clallamensis, with which it is associated, by its relatively longer disk, simple and 

less prominent external sculpture, and fewer (8 instead of 9) internal riblets. It 

is allied toP. interradiatus Gabb, but is much smaller, being only about one-half 

as large, has a much shorter hinge line, and its left valve is much more strongly 

sculptured; it also occurs in a horizon probably later than that in which P. 

interradiatus is found. 

The type of P. waylandi (U.S.N.M., No. 164924) was found with the type of 

P. clallamensis at locality 4100, 1! miles east of Pillar Point, near the mouth of the 

Pysht River, Clallam County, Wash., and a list of its associated species is given 

in the discussion under P. clallantensis. The cotype of P. waylondi (U.S.N.M., 

No. 164925), a mold of the interior of a right valve, was found at locality 4115, 2t 

miles west of Gettysburg, Clallam County, Wash., where it was associated with 

Fusus sp., L eda sp., .Macoma or Tellina sp., and Atu-ria cf. ziczac Sowerby. The 

faun~s associated with P. waylandi, at both of the localities where it has so far been 

found, indicate the lower portion of the widely distributed Oligocene-Miocene series. 

The species is pamed in honor of Mr. Russell G. Wayland, of Seattle, Wash. , 

who assisted the writer during part of his paleontological reconnaissance trip along 

the northwestern coast of Washington in the summer of 1904. 

RANGE. 

Oligocene-Miocene, 2t miles west of Gettysburg, and 1! miles east of Pillar Point. 

near the mouth of the Pysht River, Clallam County, Wash. (Arnold), 

1lf10CENE PECTENS. 

[Those known first to appear in the Miocene formations.] 

PECTEN (PECTEN) CARRIZOENSIS n. sp. 

Pl. IV, figs. 1, la, 1b, 2, 3, and 3a. 

1898. Pecten sp. indet., Dall, Trans. Wagner Free Inst. Sci. , vol. 3,' pt. 4, p. 706, line 13. 

Description.-Shell averaging about 42 millimeters in altitude, longer than 

high, inequivalve, plano-convex, equilateral, and with smooth margins; base evenly 

rounded; sides concave above. Right valve convex, ornamented by about 18 or 
60 TERTIARY AND QUATERNARY PECTENS OF OALIFOR.NIA. 

19 prominent, square, flat-topped, medially sulcated ribs; interspaces channeled and 

slightly narrower than ribs; whole surface sculptured by fine, regular, concentric 

incremental lines; hinge line -less than one-half length of disk; ears subequal, 

convex, and ornamented by concentric lines. Left valve :flat or slightly concave~ 

ornamented by about 17 prominent, equal, equidistant; narrow, convex-topped ribs, 

which are separated by :flat-bottomed interspaces much wider than the ribs; surface 

sculptured by numerous fine, regular, wavy, concentric lines; ears concave and 

sculptured by concentri~ lines. 

Dimensions.-Alt. 36 mm.; long. 40 mm.; hinge' line 15 mm.; .diameter 8 mm.; 

umbonal angle (left valve) 105° . 

This species belm:igs to the group of which P. diegensis is the living member. 

P. carn:zoensis, P. stearnsii, and P. diegensis taken in chronologie order as above 

may represent a. genetic series. The three species are alike in ~ost respects: They 

are all plano-convex, have squarish, more or less sulcated or longitudinally ridged 

ribs, convex ears on the right valve, and rather narrow, rounded ribs and concave 

ears on the left. 

P. carn:zoensis differs-from the other two rpembers of the group in the smaller 

number and less prominence of its ribs and in its relatively much shallower and 

narrower interspaces. 

The Pecten mentioned by Dall on page 706 of the Transactions of the Wagner 

Free Institute as coming from the Miocene deposits near San Diego was compared 

with the type of P. carrizoensis and found to be of this species. ' 

The type locality of P. carrizoensis is at the head of Garnet Canyon, about 

12 miles north of the Mexican boundary, in the Carrizo Creek district, San 

Diego County. The beds in this district contain a fauna different from any of 

the other known California formations, but from other considerations it is deemed 

almost certain that the deposits are of Miocene age. Just what horizon the beds 

represent has not yet been determined. (See list of Carrizo Creek district fossils 

in Part I, p. 22, and list of Santa Rosalia, Lower California, fossils under P. cerro-

• 

sensis var. rnendenhalli, p. 85.) 

The type of P. carrizoensis, which was collected by Dr. Stephen Bowers, is 

now m the collection of Delos Arnold. 

RANGE. 

Miocene. Head of Garnet Canyon, 12 miles north of Mexican boundary, San 

Diego County (Bowers); Santa Rosalia, Lower California, west of and across 

the Gul:f from Guaymas, Mexico (G. P. Merrill; E. Palmer). 

PECTEN (PECTEN) KEEPI n. sp. 

Pl. V, fig. 1; Pl. VI, figs. 1 and la. 

Description.-Shell averaging about 75 millimeters in altitude, longer than 

high, plano-convex, equilateral, and with smooth margins; sides concave above; 

lateral area very broad. Right valve ventricose and ornamented by about 20 

low, broad, rounded ribs, separated by shallow .interspaces in which are low, broad 

intercalaries; the sulcation on the interior of the valve corresponding to the 
MIOCENE PECTENS. 61 

intercalary is often quite prominent; whole surface sculptured by inconspicuous 

incremental lines; hinge line more than one-half length of disk; ears equal, somewhat convex, rather obliquely truncated and turned up slightly at the corners; 

sculpture of ears consists of fine incremental lines; byssal n?tch rather small. 

Left valve flat, with a slight tendency toward concavity near the umbo, with 

broad lateral areas and with 18 or 19 low, rather flat-topped ribs; interspaces 

somewhat wider than the ribs; surface sculptured by fine incremental lines~ ears 

concave, obliquely truncated and sculptured by more or less irregular concentric 

lines. . 

Dimensions.-A1t. 75 mm.; hinge line to ventral margin 72 mm.; long. 82 mrn.; 

hinge line 35 mm.; diameter 20 rum.; umbonal angle (left valve) 102 °. This species is distinguishable from P. vogdes1: and P. ewcavatus, which it 

resembles in general characteristics by its. greater relative length, somewhat less 

convexity, greater umbonal angle, broader lateral areas and lower ribs. 

This species is found associated with P. carr1:zoensis and Ostrea vespertina. in 

beds in the Carrizo Creek district which are probably of Miocene age. The 

type is from Alverson Canyon, San Diego County, and is now in the _collection 

of Delos Arnold. Named in honor of Prof. Josiah Keep, of :Mills College, whose 

works on California conchology have greatly stimulated the study of that subject 

on the Pacific coast. 

RANGE. 

Miocene. Eight miles north of Mexican boundary, in Alverson Canyon, Carrizo 

Creek district, San Diego County (Bowers); Santa Rosalia, Lower California, 

west of and directly across the Gulf from Guaymas, Mexico (E. Palmer). 

PECTEN (PATINOPECTEN) coosENSis Shumard. 

Pl. VI, fig. 2; Pl. VII, figs. 2 and 2a. 

1858. Pecten coosensis Shumard, Trans. St. Louis Acad. Sci., vol. 1, pt. 2, 1858, p. 122. 

1864. Pecten coosaensis Shumard, Meek (typ. err.), Miocene check list, Smithsonian Miscell. Coli. , 

1864, p. 3 (fide Dall, 1898). 

1869. Pecten coosensis Shumard, Gabb, Pal. Cal., vol. 2, 1869, p. 122. 

1898. Pecten (Patinopecten) coosensis Sh:umard, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 

1898, p. 700, pl. 26, fig. 2. . 

Description.-Shell averaging about 110 millimeters in altitude, slightly longer 

than high, valves both well compressed, equilateral, and with margins smooth; sides 

only slightly concave, and sloping at only a moderately low angle. Right valve with 

29 to 31 prominent T-rail shaped ribs, flattened and sometimes faintly dichotomous 

above, overhanging narrow, deep, almost flat-bottomed channels; whole surface 

sculptured with more or less prominent fine concentric lines; hinge line nearly 

equal to one-half length of disk; anterior ear slightly produced and sculptured by 

radiating ridges and imbricating concentric lines; byssal notch wide and deep; posterior ear rectangularly truncated, and sculptured by sharp incremental lines and 

sometimes by obsolete radial ridges. Left valve with narrower, rounded, concavesided. ribs and wider, round-bottomed interspaces; sculpture of numerous, sharp, 
62 I 

TERTIARY AND QUATERNARY PEC'l'ENS OF CALIFORNIA. 

raised, concentric lines; ears subequal, and having incremental and sometimes 

obsolete radial sculpture. 

Dirrwnsions.-Alt. 110 mm.; long. 115 mm.; hinge line 54 mm.; diameter 

26 mm. 

This fine species is distinguishable by the great number and shape of its ribs. 

Specimens found at Howe's place, northeast of Corvallis, Benton County, Oreg., 

have only from 25 to 27 ribs on the -right valve. Otherwise the specimens are 

similar to the typical form. 

Found abundantly in the Empire beds at Coos Bay, Oregon, whence the type 

came. 

RANGE. 

~Iiocene. ·Coos Bay, Oregon (Shumard; Dall; A. W. Crawford and others); 

Howe's place, northeast of Corvallis, Benton County, Oreg. (Diller). 

PECTEN (PATINOPECTEN) DILLER! Dall. 

Pl. V, fig. 2. 

1901. Pecten (Lyropecten) dilleri Dall, Nautilus, vol. 16, no. 10, Feb., 1901, P• 117. 

The original description is as follows: 

Description.-'' Shell large, averaging about 190 millimeters in altitude, rather 

compressed, nearly orbicular with a relatively t-~hort, straight, hinge line, dorsally 

rectangular, nearly smooth, subequal ears, the posterior with .3 small rihlets; a well.-

marked though shallow byssal fold; and moderately thick valves. The right valve is 

somewhat more convex and strongly sculptured, bearing 29 to 30 high, narrow, T-rail 

shaped ribs, flattened above, overhanging narrower, deep, nearly smooth channels; 

and with marked concentric imbrication, feeble on top of the ribs but articularly 

scaly at their sides. The sculpture of the left valve is less pronounced, hid de~ in the 

matrix, but apparently similar." 

Dimensions.-"Alt. 192 mm.; long. 175 mm.; diameter about 35 mm~" 

In the type the lateral edges are slightly defective, the submargins verynarrow. 

This species is close to P. puris1:maensis, and is no doubt genetically related 

to that form. Although the left valve of P. dilleN has not been seen, it is safe to 

assume from the close relationship of this specieR and P. purisimaens1:s that the 

left valve of the former is ornamented with n!lrrow, ridge-like ribs which· are 

separated by concave-bottomed interspaces relatively wider than those of the right 

valve. 

P. dilleri is so far known only from beds of probable upper Miocene . (although 

possibly lower Pliocene) age at Rio Dell~ .on the Eel River, Humboldt County, 

where the type. was collected by Mr. J. S. Diller, of the United States Geological. 

Survey. 

RANGE. 

Upper Miocene or lower Pliocene. Rio Dell, Eel River, Humboldt County (Dall; 

Diller). 
MIOCENE PECTENS. 63 

PECTEN (P ATINOPECTEN) OWENI n. sp. 

Pl. VIII, figs. 1, la, and lb. 

1888. Pecten pabloensis Cooper (not Conrad), Seventh Ann .. Rept. CaL St. Min., 1888, p. 258 ( "Foxins, 

Santa Barbara County'' record, only). 

1898. Pecten sp., Dall, Trap~ .. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 705, line 27. 

Descript,ion.-Shell 'averaging about 85 millimeters in altitude, slightly longer 

than high, inequivalve, equilateral, and with more or less serrate margins; base 

regularly rounded.; sides somewhat ·concave above. Right valve much more convex than the left, with 15 or 16 subequal, strong, elevated, squarish ribs, which 

become more or less deeply medially sulcated after about 40 or 50 millimeters in 

length; inters paces about as wide as i·ibs, channeleq and ornamented with more or 

less prominent rounded intercalary riblets; whole surface of disk sculptured by 

fine lines of growth; hinge line considerably longer than length of disk; anterior 

ear slightly longer than posterior, obsolet~ly radially ribbed, and with sharp incremental sculpture; byssal notch quite prominent and equal in width to about onethird width of ear; posterior ear rectangularly truncated and with prominent 

incremental, but nearly obsolete, radial sculpture. Left valve less ventricose than 

right; ribs quite high, narrow, and rounded; interspaces much wider than ribs, 

with round bottoms, and each ornamented by a prominent rounded intercalary 

rib; surface sculptured by numerous sharp, regular, concentric lines; ears slightly 

obliquely truncated and sculptured as those of right valve. Hinge as in P. 

cattrtnus. 

Dimensions.-Alt. 85 mm.; long. 90 mm.; hinge line 54 mm.; diameter 24 mm. 

This species is quite clo::;ely allied to P. lwaleyi, of whieh it. is. pro'9ably the 

precursor. It may be distinguished from the latter by its smaller size, greater 

convexity, fewer and stronger ribs, more prominent intercalary riblets on the 

right valve, and relatively much longer hinge line. 

P. oweni is found in a horizon which is probably low down in the Pliocene, 

and also in deposits, such as those at Foxin's ranch, Santa Barbara County, from 

which the type comee, that may be upper Miocene. Specimens of this species 

have been found in the lower part of the Purisima (Pliocene) formation north of 

the mouth of Purisima creek. There appears to be more or less of a gradation 

from P. oweni to P. healeyi as we go up in the Purisima formation. The rather 

convex, 17 and 18 ribbed forms of P. healeyi, mentioned as occurring at Lobitas 

and Purisima, seem to furnish a more or less intimately connecting link between 

the latter species and P. oweni. , 

The type of P. oweni, which is figured, is now in the collection of the 

University of California. This specimen was labeled "P. pabloensis" by Doctor 

Cooper and furnished the erroneous record of P. pabloensis from '~ Foxins, Santa 

Barbara County'' (see Cooper, 1888, p. 258). 

In the Pliocene beds of Temescal Canyon, near Santa Monica, Los Angeles 

County, P. oweni is associated with P. stearnsii, P. estrellanus var. catalinre, P. 

cerrosensis and other Pliocene species. · 
64 TERTIARY AND QUA'rERNARY PECTENS OF CALIFORNIA. 

P. oweni is associated with the following possibly upper San Pablo (upper 

Miocene) fauna at the Double Eagle wells, in the Coalinga district, Fresno County: 

Tamiosoma gregar/a, Pisania (aff.)fortis, Tresus 0) sp., Gl;ycyrneris patulus (?),and 

Saxidomus gibbosus. This fauna, although containing Tamiosorna gregaria, lacks the 

two mo~t characteristic species of the San Pablo formation of this locality, viz, 

Pecten estrellantts and Ostrea titan. The beds at the Double Eagle wells represent 

the upper part of the .San Pablo as developed in the Coalinga district, so that P. oweni 

may, therefore, be considered as only occurring in the upper· part of the San Pahlo, 

or, in other words, in beds transitional from the San Pablo (upper Miocene) to the 

Purisjma (lower Pliocene). Just above the first railroad bridge across Wartham 

Creek, Fresno County, P. oweni is associated ;With the following fauna in beds 

probably representing about the same horizon ~s those exposed at the double Eagle 

wells above referred to: Saxidomus gibbosus, Chione n. sp. (large, coarse sculpture), 

and _Tamiosorna gregaria. 

A 17-ribbed right valve of P. oweni was found 2 miles south of San Lucas, 

Monterey County, associated with Pecten estrellanus and varieties, A strodopsis 

- twnidus, Balanus estrellanus, etc. 

Named at the request' of Mr. F. M. Anderson after Josiah Owen, of Los Gatos, 

Cal. 

RANGE. 

Pliocene (lower). North of Purisima, San Mateo County (F. L. · Hess); Olinda, 

Puente Hills, Orange County (Eldridge); Lonoak, Salinas Valley, Monterey 

County (U. S. Nat. Mus. locality 3830), (Hamlin); Lewis Creek, 9 miles 

below Priest Valley, Monterey County (locality 3833), (Hamlin). Temescal 

CanJ:on, Santa Monica :Niountains, Los Angeles County (Rivers). 

Miocene (upper?) Foxins, Santa Barbara County (University of California collection); Double Eagle wells, Coalinga district, Fresno County (Eldridge); railroad 

bridge across Wartham Creek, Fresno County (Eldridge); San Lucas, Monterey 

County (Hamlin; Arnold). 

PECTEN (PATIN.OPECTEN) PROPATULUS Conrad. 

Pl. VII, fig. 1; Pl. IX, figs. 1, 1a, 2, and 2a. 

1849. Pecten propatulus Conrad, Geol. Wilkes Expl. Exped., app. 1, 1849, p. 726, pl. 18, figs. 13, 13a. 

1864. Pecten propatulus Conrad, Meek, Miocene Checklist, S. I. Misc. Coli., 1864, p. 26 (fide Dall). 

1869. Pecten propatuht.~ Conrad, Gabb, Pal. Cal., vol. 2, 1869, p. 103. (California localities excepted.) 

18H8. Pecten propatulus Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 258 (in part). 

1898. Pecten (Patinopecten) propatulus Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, 

p. 699. 

Description.-Shell averaging about 95 millimeters in altitude, as high as long, 

equivalve, equilateral, rather thin, somewhat ventrico~e and with smooth margins; 

base regularly rounded; sides straight and sloping at a rather low angle. Right 

valye with 15 or 16 subequal. squarish ribs, some of which are generally obsoletely 

medially sulcated; interspaces subequal, flat-bottomed, about as wide as ribs and 

sometimes containing faint intercalaries; whole surface ornamented with fine, sharp, I 
MIOCENE PECTENS. 65 

incremental lines; hinge line less than one-half length of the disk; anterior ear 

slightly longer than posterior, arcuate-ended, and ornamented above .the byssal area 

by 4 or 5 prominent radiating riblets, which, with the byssal area, are crossed by 

numerous fine concentric lines; posterior ear r·ectangularly truncated, and ·ornamented by seve~·al radiating riblets and numerous incremental lines. Left valve 

somewhat similar to right, but with narrower, ridge-like ribs and the broader interspace~ sometimes showing a more or less prominent intercalary riblet in the later 

stages of growth; surface, when perfect, microscopically tessellated; ears radiately 

and concentrically sculptured. 

IJimensions.-Alt. 93 mm.; long. 93 mm.; hinge line 38 mm.; diameter 12 mm. 

One of Conrad's cotypes from the Miocene of Astoria, Oreg. (U. S. Nat. Mus., 

154155), shows the ribs and surface of the disk in a perfect state of preservation. 

The ribs on the right valve are broad, squarish, and all more or less medially sulcated, and with the surface sculptured by fine lines of growth and microscopic 

tessellations. The left valve shows more or less prominent intercalaries in each 

interspace, and has the whole surface beautifully tessellated. 

This species has been confused by some authors with P. carttrintts Gould, from 

wh~ch it difi'ers by being smaller, more convex, and having fewer (15 instead of 

20) ribs, and a tessellated surface on the left valve. 

P. propatulus is common in the Astoria Miocene of the Columbia River~ A 

specimen probably of this specieR, having 15 primary ribs on each valve, intercalary 

riblets in most of the interspaces, and the typical tessellated surface, was found at 

Newport, Y aquina Bay, Oreg·. 

A variety of P. ]J1'0patulus, with possibly an average of one or two more ribs 

and the intercalaries and medial sulcations slightly more prominently developed, 

is found at Griswoldsville, San Benito County, Cal., and at several other localities in the sout ern Mount Diablo Range. At Griswoldsville P. propatulus is 

associated with the following species: Phacoides acutilineatus, Area canalis, Panopea 

generosa, Oryptomya califo1·nica, Nucula castren..r;;is, Sigm'etrtts sp., Trochita filosa, 

Dosinia sp. (thin, flat). 

A more or less close relationship appears to exist between P. propatulus, 

P. oweni, and P. healey1:. The last is distinguishable by its more numerous ribs 

(having generally 20 or more), and P. oweni by its much stronger intercalaries and 

deeper medial sulcations. P. propat ulus is found in a horizon which is probably 

somewhat lower than any in which either P. oweni orP. healeyi occur. 

RANGE. 

Miocene (middle? and upper?). Clallam Bay, Strait of Fuca,' Washington (Diller; 

Arnold); Astoria, Oreg. (Dana; Dr. H. C. Kinney, and others); Newport, 

Yaquina Bay, Oreg. (H. Hill); Point Simpson, B. C. (No. 3518, Cal. Acad. 

Sci. Coli.); Griswoldsville~ San Benito County, Cal. (Turner, Cooper). 

17260-·N o. 47 -o6-5 
66 TER'ri.ARY AND QUATERNARY PECTEN& OF CALIFORNIA. 

-PECTEN ( CHLAMYS) FUCANUS Dall. 

Pl. X, figs. 1, 2, and 2a. 

1898. Pecten ( Chla.mys) jucanus Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 704, pl. 26., 

fig. 7. . 

1904. Pecten ( Chlamys) jucanus Dall, Harriman Exped. Repts., .Alaska· geology, Neozoic invert. 

fossils, p. 113. · · 

Description.-Adult shell averaging nearly 100 millimeters in altitude, about 

as long as high, inequivalve (the . left being the more conve~), equilateral, 

moderately thin, and with nearly smooth margins. Right valve with from 14 to . 

17 more or less unequal, prominent, rather•squarish, radiately sfriate ribs, between 

which (especially the anterior and posterior ones) are. occasionally intercalated 

small riblets; . interspaces unequal and averaging somewhat narrower than the 

ribs; whole surface of disk sculptured ·by rather prominent lines of growth and . 

a fine subsidiary tessellation; hinge line longer than one-half length of disk; ears . 

equal in length; the anterior rather narrow and sculptured by ! . prominent radials 

and fine, imbricating, inc~emental lamellre; . the posterior rectangularly truncated 

and sculptured by more, but less prominent radials and fine concentric lamellre; 

byssal notch profound. Left valve usually having 15 or 16· unequal, prominen't, 

convex-topped ribs, the median one generally being · stronger than the rest, with 

the second or third one from it on .each ·side only a ·little less prominent; the 

prominent ribs, especially the median . one, is generally surmounted by elevated 

imbricating scales; the other ribs are simply radially striated, as are the interspaces, which often carry one or more elevated riblets; the subma1:gins are radially 

threaded, as are the suhequal ears, which are . rectangularly truncated, and also . 

bear marked concentric lamella~; the fine subsidiary tessellation is ·also present on ·. 

well-p1·eserved specimens of this valve. '-fhe resilial pit 1s of :n!Oderate size, and 

the cardinal edge is deeply grooved parallel to and just below the margin. The 

interior of both valves reflects the external ribbing. 

Dim isiods~ -Alt. 85 mm.; long. 80 mm.; convexity of tight valve 5 mm.; of 

left valve 15 mm.; hinge line 50 mm. · 

The difference between .the convexity and ribbing of the two valves, together 

with the variation · in size, shape, and ornamentation of the individual ribs of the 

same valve, are the promnient characteristics of this species. It is not closely 

allied to any other species of · Ohlamys, but, instead, shows in its sculpture some · 

affinity to certain species. of Patinopecten:·. . . . 

The type of 1>.fucanus (U.S.N. M., No. 107790) is the ·.mold of the exterior 

and interior (a cast of the · former being Pl. X, fig. 2) of a left valve which was 

found by Mr. J S. Diller in the Miocene sandstone ·on the coast just east of 

Clallam Bay; Clallam County, Wash. It was assodated in ·the sandstone formation 

with the following species: Sig'aretus sp.; Orepidula sp., De'ntaliuin sp., Hytilus . 

sp., Hactra or Spisula sp., Venericardia sp., Nucula (cf.}decisa Conrad, Leda sp:, 

Tellina ( cf:) arctata Conrad, Tellina sp., Chione sp. 

The writer found P. fucanus at several localities (U. S. Nat. Mus. localities 

4074, 4077, 4081, 4082) on the coast between Clallam Bay and the mouth of the · 

Pysht River, 7 miles farther east. At all of these places it was associated with 

• 

.. 
MIOCENE PECTENS. 67 

characteristic Miocene fossils, among which was a large Pecten (probably propatulus 

Conrad) with medially sulcated ribs on the right valve. 

RANGE. 

Miocene. Between Clallam Bay and Pysht River, Clallam 9ounty, Wash. (Diller; 

ArnoJd); north end of Popoff ISland, Alaska (Dall). 

PECTEN (CHLAMYS) HAMLIN! n. sp. 

Pl. XI, fig. 2. 

Description.-Type somewhat distorted but originally about 60 millimeters in 

altitude, and probably somewhat shorter than high; moderately convex; base 

evenly rounded; sides nearly straight. Right valve with 4 broad, squarish ribs, 

each ornamented above by about 5 prominent imbricated radiating ridges, and 

separated, by relatively narrow interspaces; hinge line more than one-half length 

of disk; anterior ear much longer than posterior and ornamented by several 

imbricated radiating ridges; byssal notch quite prominent; posterior ear short and 

radially ridged. 

Dirnensions.-(Of the distorted type.) Alt. 60 mm.; long. 68 mm.; hinge line 

40 mm.; diameter 24 mm. 

This species ·is closely allied to P. wattsi, but is distinguishable from the 

latter species by its relatively broader ( ?) disk and longer hinge line. The characteristics C?f sculpture are approximately the same in the two species. 

The geologic position of P. hamlini is somewhat uncertain, although .the 

meager fauna with which it h; associated at the type locality points toward its correlation with the Vaqueros or lower Miocene. The type of P. hamlini (U.S.N.M. 

No. 164844) was collected by Mr. Homer Hamlin near the head of Slack's Canyon, 

in the Mount Diablo Range, Monterey County, where it was associated with 

P. estrellanus Conrad, Oh£one n. sp. (large, and with coarse sculpture), Ohione 

(cf.) mathewsonii Gabb, and Mactra (aff.) catilliformis Conrad. 

A specimen, which is probably a left valve of P. hamlini, was found associated with Pecten branneri in the lower :Miocene at Tuff Hill, near Stanford 

University, Santa Clara County. This specimen has three widely separated, narrow, ridge-like ribs, and the interspaces are ornamented by a number of rather 

coarse radiating rib lets; altitude 31 millimeters. 

RANGE. 

Miocene (lower?). Locality 3851, U. S. Nat. l\'Ius., head of Slacks Canyon, Mount 

Diablo Range, Monterey County (Hamlin); Stanford University (Tuff Hill), 

Santa ·clara County (Arnold). 

PECTEN ( CHLA1UYS) NUTTER! n. sp. 

Pl: XI, figs. 3, 4, and 4a. 

Description.-Shell averaging about 65 millimeters in altitude, slightly higher 

than long, i~equivalve, equilateral, more or less ventricose, and often showing 
68 TRRTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

several constrictions or undulations of interrupted growth; margins somewhat 

coarsely serrate; base regularly rounded; sides straight, and forming an acute 

al_lgle at the uul.bo. Right valve with . about 8 to 10, unequal, rather prominent, 

flat-topped ribs, each of which is channeled by one or rnore deep, narrow, concave 

sulcations which divide the primary rib from umbo to margin into two or more 

generaH:y unequal but evenly con':"ex riblets;· interspaces somewhat narrpwer than 

the ribs, and containing from l to 3 prominent rounded riblets; the riblets become 

more numerous and the major ribs less. prominent anteriorly and posteriorly; the 

minor sculptu!·e consists of squamose lines of growth, which .are more prominent 

on the ribs, and beautiful microscopic checkered tessellation which is best developed 

in the major and minot; interspaces; hinge line from two-fifths to nearly one-half 

length of disk; anterior ear prominent and sculptured by 5 ·or 6 elevated · radiating ridges and imbrieating concentric lamellre; byssal )lotch moderately deep; 

posterior ear rectangularly truncated, a little less than one-half length of anterior, 

and similarly but less prominently sculptured. Lett valve with unequal, rather 

narrow, convex ribs, the alternate ones being more prominent than · those intei·-

mediate; extremities of the ribs sometimes ornamented by -longitudinal riblets; 

interspaces of about equal width to the ribs, . and ornamented by one or three 

alternately prominent' intercalaries; surface sculptured by imbricating incremental 

lines; the constrictions, when present, are more pr~nounced in this valve; ear~ 

sc~lptured similarly to those of the right valve. Hinge with a pair of prominent 

cardinal crura adjacent to the umbonal pit in the right valve. 

Dfmensions.-Alt. 64 mm.; long. 57 mm.; hinge line 2-7 rrim.; diameter 21 mm. 

· This species is allied to P. parrneleei and P. wattsi but is distinguish~ble by 

having a larger number of ribs, which are also n~rrower and more coarsely radially 

sculptured. The Miocene forms of P. m.ttteri have more prominent and deeply 

sulcated ribs on the right valve, are generally more convex and more prominently 

constricted, and have relatively longer posterior ears than the later :forms. 

I->. n1.dteri, so far as known, ranges from the Mount Hamilton Ra:r;Ige ~Iiocene to 

the lower Pliocene. It is found rather abundantly in a certain la.ver in the sea cliff, 

one-half mile south of the mouth of 8an Gregorio Creek, San ·Mateo County, 

associated with a characteristic lower Pliocene (Purisima) fauna. The species is 

named in honor of Mr. Edward Hoitt Nutter, who has rendered the writer much · 

valuable assistance in the preparation of this paper.· The type is from San 

Gregorio, San Mateo County, and is now in the ·collection of the · depa.rtment of 

geology, Stanford University. · 

RANG.E. 

9 Pliocene (lower). Purisirria to Pescadero, San 1V1ateo County (.J. P. Smith, W. R. 

Hamilton, Arnold); Kreyenhagen's ranch, Fresno Coun.t,y (Watts). 

Miocene (upper). Near Mount Hamilton, 8anta Clara County (No. 58.05, Cal. St. 

Min. Bur. Coli., collected by Mrs. A~ E. Bush). 

.. 

'. 
• 

• 

MIOCENE P'CTENS. 69 

PECTEN (CHLAMYS) SESPEENf'IS n. sp. 

Pl. VIII, figs. 2, 2a, and 3. 

1888. Pecten hastatus Cooper (not Sower by), Seventh Ann. Rept. Cal. St. Min., 1888, p. 257 (Miocene 

of Estrella, San Luis Obispo County?). c; 

Description.-Shell averaging about 50 millimeters in altitude, higher than long, 

inequivalve but both valves equally slightly convex, rather thin, and equilateral, 

except for ears: Right valve. with about 9 pairs of narrow, rounded, nearly smooth 

ribs, each pair being· separated from the adjacent ones by interspaces, which are generally slightly wider than the interspace between the members of the pair; surface 

sculptured by incremental lines; hinge line about two-thirds length of disk; anterior 

ear much produced, sculptured by several prominent radials and numerous incremental lines; posterior ear over one-half as long as anterior, and sculptured similarly; 

byssal notch prominent. Left valve with about nine prominent, narrow, squarish, 

somewhat convex-topped ribs separated by much broader interspaces, along the 

bottom of which run one or more thread-like intercalaries of greater or less prominence; ears similar to those of the right valve. 

Dimensio'ns.-Alt. 37 mm.; long. 30 mm.; hinge line 19 mm.; diameter 12 mm.; 

umbonal angle 75° . · 

This species is closely allied to, and is probably the prec~rsor of P. hastatus 

Sowerby. It corresponds to P. ha~tatus in size, shape, and number of major ribs, 

but differs from the latter in having longer anterior ears and scarcely any secondary 

sculpture of minor riblets and scaly surface. P. sespeensis approaches more closely 

to the smooth form of 1-). hastatus found in the Pliocene, but may be easily distinguished from that form by its longer posterior ears and lack of much secondary 

~culpture. . I 

The only specimens of this spkcies known are rather poorly preserved casts, 

· with now and then small fragments of the shell hanging to them, which come from 

beds of lower Miocene age, locally .known as "oil rocks," in the Sespe oil district, 

Ventura County. Type and coty"Re, No. 12480, California State Mining Bureau. 

Other specimens of the same species, Nos. 12427 and 14759 C. S. M. B. On, Tar 

Creek, Ventura County, Mr. Eldridge found P. sespeensis associated with Turritella 

(~f.) hoffmanni, Ostrea sp., and Modiolus sp. 

RANGE. 

Miocene (lower.) Sespe oil district, Ventura County (Watts); Tar Creek, Ventura 

County (Eldridge). 

PECTEN (CHLAMYS) SESPEENSIS var. HYDEI n. var. 

Pi. V, figs. 3, 3a, and 3b. 

1903. Pecten ( Chlamys) hydei Arnold. MS. 

Description.-Shell averaging about 45 millimeters in altitude, much higher 

than long, subequivalve, slightly convex, and subequilateral, except for ears; 

anterior sides more concave than posterior; base regularly rounded; umbonal angle 
70 TER'l'IARY : AND , QUATERN fRY PECTENS OF CALIFORNIA_ 

comparatively small. Right valve with · about 20 subequal, promi..1ent, rounded, 

so mew hat imbricated ribs, which in'crease gradually in number by division and 

intercalation as the ~hell grows; interspaces somewhat narrower than ribs and often 

containing one or two thread-like intercalaries; ears as in P. hastatus var. her1:cius 

except less imbricated, and the posterior relatively lat:ger. Left valve similar in 

every respect to right. · . 

Dimensions.-Alt. 46 mm.; long. 39 mm.; diameter 13 mm.; umbonal angle 82° . 

This variety is characterized by the nearly uniform ·size of its ribs and interspaces. The shell has a tendency to contract somewhat upon reaching an altitude 

of about 35 or 40 millimeters. P. var. hydei is closely allied to the typical P. 

sespeens1:s, but may usually be distinguished by its more nearly eqmil ribs, which 

are generally more strongly imbricated. 

In a tributary of Little Sespe Creek, Ventura County, Mr. Eldridge found P. 

var. hydei associated with ScuteUa fairbanksi, Ostrea sp., Area sp., and Balanus. 

Near the Torrey wells, Ventura County, the same gentleman found. it with Mytilus 

mathewsonii, and Ostrea (aff.) titan. In the Ojai Valley it occurs with Pecten 

rnagnolia and Chione ~. sp. (large; coar.se sculpture). · 

The type specimen is from Lynch's Mountain, Monterey County, where it was 

found · associated in the ·lower Miocene (Vaqueros. s·andstone) with Turritella hoff- . 

manni, Pecten estrellanus, and ·other species characteristic of· this horizon. It· is 

now in the collection of Delos Arnold. Named ·in. hqnor of Prof. James M. Hyde, 

of the University of Oregon. 

RANGE. 

Miocene (lower). Lynch's Mountain, Monterey County (Arnold); vicinity of Little· 

Sespe Creek, Torrey oil wells, and Ojai Valley, Ventura County (Eldridge). · . 

PECTEN (L!ROPE(!TEN) BOWERS! n. sp. 

PL XII, figs. 1 and 2; PLXIII, figs. 1 and 1a. 

1856. ? Pecten nevadan us Conrad, Pac. R:. R. Rept., vol. 5, p. 829; pl. ~, fig. 77. 

Description.-Shell averaging about 150 millime~ers in altitude and length, 

inequivalve, equilateral, rather thick, ventricose, an.d with smooth margins; hase 

regularly rounded; sides sloping, the anterior ' ones · slightly . concave upward. ·. 

Right valve considerably less ventricose than left, the surface of the disk being 

almost flat until an altitude of 50 or 60 millimeters is· reached, when it begins to 

be more or less convex; s~rface ornamented with about 18 subequal, prominent, 

rounded ribs, which; with. the · interspaces, are obsoletely radiately striate and 

crossed by fine wavy incremental lines; the ~ibs tend to· become smaller toward 

the sides· of the disk, there being a varying number of riblets near the sides in 

different specimens; interspaces subequal; .round bottomed, about as wide as the 

ribs, and sometimes containing an auxiliary riblet; hinge line about three-fifths 

length of shell; ears about equal in length, ·anterior ear divi~ed into two nearly 

equal parts by a line radiating from the apex, the part above . the dividing ·line 

being ornamented by 3 or 4 radiating ribs and concentric lines while the lower 

part (byssal area) is ornamented by imbricating . inc:remf:mtai lines which are convex . 

•) 

• 

.. 

' 
MIOCENE PECT-ENS. 71 

toward the apex; byssal notch wide and of medium depth; posterior ear rectangularly truncated, radiately ribbed, and crossed by concentric incremental lines. 

Left valve prominently and evenly ventricose; sculptured the same as the right 

valve except that most of the interspaces contain an auxiliary riblet; anterior ear 

arcuate ended, radiately ribbed, and with concentric incremental sculpture; posterior 

ear as in right valve. · 

Dimenwt:ons.-Alt. 150 rum. ·; long. 150 mm.; hinge line (restored) 90 mm.; 

diameter 55 mm . . 

This species is distinguishable by its large size, almost smooth rounded ribs, 

and the greater convexity of the left valve. The flat surface of the right valve 

near the apex is 'also a very noticeable characteristic. P. bowersi is. placed in the 

section Lyropecten because of its hinge and general affinity to the group. It, 

however, lacks the radial seeondary sculpture found developed to·a greater or less 

degree on most of the species of this group, and is also different from the other 

members examined by the writer in having the left valve noticeably the mo~e 

convex. 

P. bowersi ranges from the lower to possibly the middle Miocene, being found 

associated in some localities with P. magnol1'a, and in others with P. discus. 

The type which is figured is from Santa Inez Canyon, Saata Barbara County, 

and is now in the collection of the University of 0alifornia. Named in honor of 

Dr. Stephen Bowers, of Los Angeles, one of the pioneer geologists of southern 

California, to whom the writer is indebted for ·much valuable material and information used in the preparation of this paper. 

RANGE. 

Miocene (middle~). Gillis's ranch, 10 miles southwest of Paso Robles, San Luis 

Obispo County (J. P. Smith). 

Miocene (lower). Santa Inez Canyon, Santa Barbara Oounty (Voy; J. H. 'Vilson); 

La Panza Creek, San Luis Obispo County (Fairbanks; R. Moran; Arnold); 

Barker ranch, and ''top of hill" at Long Tom mine and Miller Bros. ranch 

east of Annette P. 0., Kern County (Watts; Arnold); 30 miles north of Santa 

Monica and 1 mile from oeean, Ventura County (R. E. Maynard); Santa Monica 

Mountains, Los Angeles and · Ventura counties (Bowers). Station No. 550, _ 

Santa Ana Mountains (Watts). 

PECTEN (LYROPECTEN) CRASSICARDO Conrad. 

Pl. XVI, figs. 1 and 1a; Pl. XVII, figs. 1, 1a, and 1b; Pl. XVIII, figs. 1, 2, and 2a. 

1856. Pallium crassicardo Conrad, Proc. Acad. Nat. Sci. Phila., 1856, p. 313. 

1857.? Spondylus [=;Pecten] Estrallensis Conrad, Proc. Acad. Nat. Sci. Phila., first series, vol. 8,. for 

1856, 1857, p. 315. 

1857.? Spondylus [=Pecten] Estrellanus Conrad, Pac. R. R. Rept., vol. ·7, 1857, p. 191, pl. 1, fig. 3; not 

Pallium [ =Pe£len] estrellanum Conrad, Pac. R. R. Repi:., vol. 6, pt. 2,1856, p. 71, pl. 3, fig. 15. 

1863. Pecten crassicardo Conrad, Proc. Acad. Nat. Sci. Phila., 1862, p. 291. 

1867. Lyropecten crassicardo Conrad, Am. Jour. Conch., vol. 3, 1867, p. 6. 

1869. Liropecten crassicardo Conrad, Gabb, Pal. Cal., vol. 2, 1869, p. 105 (in part, at least). 

1888. Liropecten crassicardo Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 246 (in part, . 

at least). 
72 TEih'I.ARY AND QUATERNARY PECTENS OF CALIFORNIA. 

1894. Pecten estrellanus Conrad, Cooper, Bull. Cal. St.~ Min. Bureau, No.4, pt. 5, 1894 p. 57 (in part). 

1898. Pecten magnolia Dall, Trans, Wagner Free Inst. Sci., vol. 3, pt. 4, p. 702 (in part); not Pecten 

magnolia Conrad, Pac. R. R. Rept., vol. 7, 1857, p. 191, pl. 1, fig. 2. 

1901. Pecten magnolia Dall, Nautilus, vol. 14, 1901, p. 117 (in part); not P. magnolia Conrad, 1857. 

1904. Pecten (Lyropecten) _diabloensis Arnold, MS. (a distorted specimen of P. crassicardo being the 

type). -

D escription. _:_Adult, shell averaging about 1~0 millimeters in altitude, about as 

long as high, inequivalve, convex, equilateral (except for ears)~ thick, and generally 

prominently and abruptly constricted or undulated one or more times near the 

umbo and som~times at later stages of growth; sides nearly straight; base regularly 

' rounded; margins smooth. Right vah;e _with ·14 to 17 prominent; pei·pendicul~tr~ 

sided, convex topped ribs, which are separated by rriore or less deeply channeled, 

,flat-topped, conv x-bottomed interspaces somewhat. narrower than the ribs; whole 

"surface of ribs and interspaces sculptured by numerous radial strire and fine, 

minutely wavy, imbricating, concentric lines~ hinge line about four-sevenths length 

of disk; anterior 1 ear somewhat produced, subarcuate laterally and sculptured by _ 

about 5 prominent radial. ridges and numerous fine imbricating incremental lines; 

posterior ear about three-fourths length of anterior, sculptured simil::trly, but 

slightly less prominently, and ·rectangularly truncated. Left valve similar to right, 

except that the rios are · narrower, and the interspaces eorrespondiogly broader; 

ears similar to posterior one of right valve. Hinge with a deep resilial pit, on 

each 8ide of which are several prominent lateral crura or teeth. 

Dirnens1.:on8.-Alt. 140 mm.; long. 138 mm.; hinge line 85 mm.; diameter 50 

mm.; umhonal angle 105° . -

The tops of the ribs -sometimes overhang· the inters paces and also sometimes 

appear smooth. Great variation is shown in regard to the number, abruptness, and 

prominence of the constrictions on the disk. One or two are generally present near 

the umbo in most specimens, and some show as many as six or seven at different · 

periods of growth. The spe imens of this species from Orange County are generally 

freer from constrictions and the disks are usually more compressed than in the forms -

from central California; otherwise the former are .normal types. 

P. crassicardo is characterized by its comparatively few· ribs, which, with the 

inters_paces, . are more or les~ prominently striated. It is distinguishable _ from P. 

ashleyi, by its relativ..ely 'much greater length, fewer ribs, and tendency_ to be constricted at different stages of growth; distinguishable from P. magnolia, with which ~ 

it is often confused, by its more numerous and much narrower ibs, relatively shorter 

hinge line, more prominently striate eal's, and its _ t~ndency to become constricted; 

· distinguishable from P.· estrellanus, with which it is often associated, by its fewer 

and rather finely striate rihi:! and lack of a major intercalary i·iblet (the bottoms of 

the interspaces of P. crassicardo beir1g striate rather than containing a riblet). Some 

of the lateral ribs and int~rspaces, and the surface near the periphery of the disk in 

adults of P. estre1lanus generally show sculpture similar to that characteristic of 

P. crassica1'do. · 

P. crassieardo -is found abundantly in the San Pablo, or upper Miocene formatio_n of central California, and also in beds of possibly lower Miocene age in southern 

· California. · 

• 
MIOCENE PECTENS. 73 

Mr. Homer Hamlin and the writer found _P. crassica1·clo associated with th~ following fauna in beds of somewhat uncertain age, in a small ravine one-half mile south 

of J. ·C. Griffin's ranch house, Priest Valley., Monterey County; P. discus Conrad, 

Agasoma (a .if.) barkerianum Cooper, _j_1fytilus (a if.) mathewsonii Gab b, Venus pertenuis 

Gabb, and Ostrea titan Conrad . 

. In the Valcito Valley, Fresno County, Mr. H. W. Turner found P. crassicardo 

with Venus perten.ttis, .Dosin,ia ( qf) ponderosa, and Tellina sp. 

Mr. Eldridge found P.- crassicardo associated with the following species in beds 

of probable lower Miocene age on the ridge between the Upper and Lower Ojai 

valleys~ Ventura County: Pecten lornpocensis, Turritella ( cf.) hoffmanni, Phacoides 

sp. (fiat), Ostrea sp., Nassa sp., .Dentalium sp., Chione sp., Lecla sp., Balan/us sp., 

and Tritoniuni, or .F1tsus sp. 

Dr. Stephen Bowers has found P. crassicarclo with the following species in the 

Miocene of Laguna Canyon, San Joaquin Hills, Orange County: Pecten estrellanus, 

Glycymeris ~ sp., Turr·itellr£ hoffinanni, Chione n. sp. (large, coarse sculpture), 

Agasoma kernian1tm., and Gyrodes ? sp. 

A beautiful specimen of P. crassicarclo in the National ~Iuseum (No. 154154) 

labeled from "'California" is associated in the matrix with Saxidomus gracilis, Tresus 

nuttalli, and Litorina remoncli. As the last mentioned species is found only at 

Kirker Pass it is safe to assume that this magnificent specimen (which is figured) is 

from that locality. 

The type of P. crassica1'do (Pl. XVIII, fig. 1), which is now in the collection 

of the Philadelphia Academy of Natural Sciences, is simply labeled "California. 

Pres. by Dr. Wilson." 

RANGE. 

J\'Iiocene (upper). San Pablo Bay, Contra Costa County (Merriam, Arnold, and 

other~s); Kirker Pass~ Contra Costa County (U.S.N. M.); MountDiablo~ Contra 

Costa County (Pioche collection, Univ. Cal.); Scott Valley, Santa Cruz 

County (~liss L. J. F. Hecox); Cammatta ranch and San Juan Valley, east of 

San Luis Obispo~ San Luis Obispo County (Fairbanks, lVloran~ Arnold); Priest 

Valley, 'Monterey County (Hamlin, Arnold); San Ardo, Monterey County 

(Fairbanks, Hamlin, Anderson, "-r. C. Dudley for Cal. St. Min. Bureau, 

Arnold); Quailwater Creek, San Luis Obispo County (Anderl:lon); Ventura 

County (No. 12772, C. S. M. B.); Sunset district, Kern County (Eldridge); 

Valcito Valley, Fresno County (Turner). 

Miocene (middle or lower). Devils Den, Kern County; Ojai Valley, Ventura 

County (Eldridge); ~ El Toro and Laguna Canyon, Orange County (Bowers, 

Arnold). 

PECTEN (LYROPECTEN) CRASSICARDO Conrad var. HAMILTON! n. var. 

Pl. XI, figs. 5 and 6 . 

.Description.-Adult shell averaging about 60 millimeters in altitude, subequivalve, equilateral, convex; sides concave above; margins smooth. Right valve 

with 15 to 17 prominent convex-topped ribs~ separated by interspaces narrower 

• 
• 

. · 

74 TERTIARY AND QUATERNARY PEC'J'ENS OF CALIFORNIA. 

than the ribs; surface of. ribs and interspaces sculptured by rather coarse 

radiating lines and imbricating incremental lamellro; anterior ear longer than the 

posterior, and with 4 prominent, . finely imbricated radials; byssal notch rather 

deep; posterior ear rectangularly truncated, and with radial and concentric . 

sculpture. Left valve similar to right, except with slightly · wider interspaces. 

The disk of this variety is generally contracted after reaching an altitude of 40 

millimeters or more. . 

Dimensions.-Alt. 40 mm.; long. 47 mm.; hinge lineabout. 30 mm.; diameter 

about 14 mm. 

This variety is closely allied to the typical p; crassicardo, and probably is 

the ancestral form: It is distinguishable from the latter by its smaller size 

when adult, narrower, lower, and more strongly and evenly convex-topped ribs, 

narrower anterior ear on the right valve, and tendency to become more 

contracted, and consequently more convex when adult or at an altitude of about · 

60 millimeters. P. var. hamiltoni resembles P. estrellanus in size and shape, and . 

in the earlier stages of growth is almost indistingui_shable on acc.ou~t of having . 

·but a single line down the middle . of the interspace, which resem hle~ the inter- ·_. 

calary riblet of P. estrellanus. A£ter attaining ·an altitude of ··about· ·so millim~ters 

the two species ·are . easily separated, as at that stage· of growth the radial 

striation becomes apparent on the ribs of P. var. hamiltoni, and the radial line 

in the interspace is supplemented by others, thus . ornamenting the interspace 

with several radial lines rather than with an intercalary riblet, as in P. estrez:.. 

lanus. · The tendency to undulations caused by temporary contractions in the 

growth of the disk near the umbo is often exhibi~ed to a slight degre~ in some 

specimens of P. var. harniltoni. 

This variety is known only from the Mount Hamilton Range, where it is 

quite common from a few miles south of Mount Hamilton to Mount Diablo, in_ 

Contra Costa County. P. var. hamilton1; occurs in the ·horizon of the Miocene 

which is so well developed in the -vicinity of Alum Rock Canyon, Santa Clara 

County. The type is from this locality, and is now in the U .. S. National Museum 

(No. 164845). Nanied in honor· of Mr. W. R. Hamilton, of Bodie, CaL 

RANGE. 

Miocene (upp~r). Alum Rock Cany.on, Santa Clara Cou~ty (Turner; J. P. Smith; 

Arnold); Mount Hamilton, Santa Clara County (Crawford}; Mount Hamilton 

Range in Alameda County (Yates). 

PECTEN (LYROPECTEN) ESTRELLANUS Conrad; 

Pl. XIX, figs. 1 and 1a; Pl. XX, figs. 1, 2, and 2a; Pl. XXI, figs. 1, la, 1b, 2, 2a, and 2b. 

1856. Pallium estrellanum Conrad, Pac. R. R. Rept., vol. 6, pt. 2, 1856, p. 71, pl. 3, fig. 15. 

1856. Pallium estrellanum Conrad, Pac. R. R. Rept., vol. 7, pt. 2, 1856, p. 191, pl. 3, ·figs. 3 and 4; 

1857. Pallium estrellanum Conrad, Proc. Acacl. Nat. Sci. Phila., vol. 8 for 1856, p. 313. 

1863. Lyropecten estrellanus Conrad, Proc. Acad. Nat. Sci. Phila., vol. 6 for 1862, p. 291. --

1863. Lyropecten vola:formis Conrad, Proc. Acad. Nat. Sci. Phila., vol. 6 -for 1862, p. 291. 

1869. Liropecten estrallanus Conrad, Gabb, Pal. Cal., vol. 2, 1869, p. 105 . 

·. 
MIOCENE PECTENS. 75 

1888. Liropecten estrellanus Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 246. 

1894. Liropecten est:rellanus Conrad, Cooper, Bull. Cal. St. Min. Bureau, No. 4, pt. 5, 1894, p. 57, pl. 5. 

:figs. 65-67 (text only in part). 

1898. Pecten (Lyropecten) Heermanni Dall, Trans. Wagner Fre.e Inst. Sci., vol. 3, pt. 4, 1898, p. 701 

(not P. Heermanni Conrad, Proc. Acad. Nat. Sci. Phila., vol. 7, 1855, p. 267, which is P, 

caurinus Gould). 

De8cription.-Shell averaging about 90 millimeters · in altitude, somewhat 

longer than high, equivalve, equilateral, of ··medium thickness, generally quite 

ventricose, and with margins more .or less serrate; base evenly rounded; sides 

sloping, slightly concave above. Right yalve with 16 to 20 prominent, squarish 

ribs separated by channeled interspaces which are narrower than the ribs; interspaces each with one sharply outlined, squarish riblet in the middle; surface 

. sculptured by fine raised incremental lirulre which .loop back over the ribs and 

riblets, and, on the anterior and posterior portions of the disk, by radiating strire, 

which' increase in number as the periphery of the disk is approached; hinge line 

straight and nearly equal to one-half length of disk; ears equal; anterior ear 

arcuate in front and ornamented above byssal area by three or four radiating 

ridges and numerous incremental lines; byssal notch sharply defined; byssal area 

with incremental sculpture only; posterior ear with slightly concave end ~nd ornamented by 5 or 6 radiating . ridges and more .. or less prominent incremental lines. 

Left valve with the ribs narrower and having more sl.oping side.s and rounded 

tops thah those of the right; interspaces wider; auxiliary riblets inclined to be 

dichotomous near the ends in the more mature specimens; the looping incremental lirulre and the secondary radiating lines apparently more highly developed 

in this valve than in the right; ears similar to the posterio[ ear of the right valve. 

Dimensions . .-Alt. 93 mm.; long. 105 mm.; hinge line 50 mm.; diameter 47 mm. 

This is a most variable species in size, shape, and sculpture, the above 

description applying to the most common form. One peculiar characteristic 

sometimes shown by this species is a contraction or interruption in the growth at 

different stages. See Pl. XXI, fig-s . .1, la, lb. Up to the :first interruption the 

sculpture is generally simple and quite constant, but afterwards it (especially the 

radial) becomes more complex, the riblets in the interspaces becoming dichotomous 

. and the radiating lines becoming more numerous and prominent. 

The variety of this species described as Lyropecten volmforrnis by Conrad is the 

extremely convex type. Conrad thought that the valves were unequal inthe very 

convex shell, but in all the . specimens of this sort examined by the writer, both 

valves show an equal amount of convexity. This very ventricose form is common 

near Coalinga, Fresno County, in beds of probable San Pablo (upper Miocene) age. 

Specimens of this species from Catalina Island show more ribs (right valves, 

19 to 21) than the average, and also appear to be slightly inequivalve, the left valve 

. being the more ventricose. The characteristic interruption . and constriction took 

place on most of the Catalina specimens at an altitude of about 55 millimeters. 

A specimen of this species from San Benito County, collected by Mr. H. W. 

Turner, is very convex, and shows beautiful equal, equidistant, looped lamellre over 

the surface of the valve. The intercalary riblets on this spechnen are sharpiy 

defined. · 

.. 
"· 

76 .· TERTIARY• AND QUATERNARY PEC'.rENS OF CALIFORNIA.• 

Bet~een . s~n: Luc~s a;nd .San .· A:rdo, Monterey County, Mr. Homer Hamlin 

found a specim n of_,P. estrellanus measuring 125 millimeters in altitude, which 

shows tlie striations well developed . on the anterior and posterior ribs and near the 

·ends of the· middle ribs and~ interspaces.- The. flat forms grading into var. cdtalin<J3 

~ere found associated at this locaJity with the typical eonvex shells. . 

In central California, especially .in the ·region about the Salinas Valley, .the . 

P. estrellan'us· associate'd with the la:rg(3 Ostf.ea: titan,. Conrad usually have nineteen 

ribs,e .'\Vhile ._t~?se found in the horizon of Qstrea .palmula Carpenter and Chm·us 

belcheri Hinds ave~age two or- three less. · ':1-'he latter horizon appears to be above 

tha~ ~{ ;0:. ~tan. .. " . .' . . . . . _ lp the· r~gion atourid Coalinga, Fresno _County, P. estrellanus is very common, 

and. is usmiVy.: a~sociate~ 'with: Tamiosuma · grer;aria, Ostrea titan, Venus pertenuis, 

. Chione n . .sp ~ (l~rge; .. coarse sculpture)~ 4~ca canalis, etc., in· beds ·which may be. the 

· equivalenf of the · S~n ',Pablo·. formation. ·The significance o£ the total absence of 

. P. estrellanus from the. type .locality of the San ,Pablo is not at present known. . 

So far ·as is definitely ~nown, this species. is confined to the Miocene, where it is 

found in nearly every comity of Oiliforuia from Napa to Orange. In osome places 

it is.found . associat~d wfth a characteri~tic lo.wer Miocene farina, while at others the 

same ·form will be found in .. th_e San Pablo O!: upp(w Miocene. . . 

RANGE. · 

Miocene: Napa County (Lockwood); Solano Coun'ty (Cooper); Alameda County . 

(Yates); Mount Hamilton Range (J. P. Smith; Arnold); Santa Cruz Mountains 

(Ashley; Arnold); San· Lucas- and San Ardo, lVlonterey C~unty (Anderson; 

Hamlin); Ly.nch's1\1ounta.in, Mo;nterey County (C. S. Smith); 15 miles north- : 

east of San Miguel, Monterey County (Hamlin; Arnold); S~n· Luis Obispo and · 

Santa Barbara counties (Conrad; Fairbanks; R. Moran; J. H. Wilson; Arnold, 

and others}:;· Coalin,ga; Fresno County (Watts; Eldridge; L. D. O'Neal); ~ San 

Benito County (Turner); Santa Ana Range, Qrange County (Watts); El Toro, 

Orange County (.Bowers). . I '. • • 

PECTEN (LnoPECT~N) . ESTRELLANUS Conrad var. CATAJ1IN1E n. · var. 

Pl. XX, figs. 3, 3a, and 4 . . ' . . 

.Description.-Shell ave~·aging about 65 millimeters in altitude, considerably 

longer than high, equivalve, · equi'lateral, of ' Il1edium thickness, only slightly 

ventricose, and with margins more . or less serrate; ·base evenly rounded; sides 

only slightly concave above. Right valve with -19 or . 20 square, flat-topped ribs, 

all of which are sculptured by incremental lines and the 3· or 4 ·outer ribs on 

each side · by more . or less prominent radial lines; !nterspaces narrower than ribs 

and ornamented by a· prominent squarish riblet; hinge line over .one-half length 

of disk; anterior ear arcuate in front, with rather · small · t>yssal notch, and orna-· 

mented . by concent~ic lines and 5 or 6 rather prominent radiating ridges; poRterior ear with concave end and ornamented by numerous fine radiatin.g ridges and. 

incremental lines. Left valve similar to right except that the ears are both like 

the posteljor one ~f "the right valve, ·and. the inte'rspaces are relatively a little 

wide!'. 

. .... 
.. 

. . 

MIOCENE PECTENS. 77 

Dirnensions.--Alt. 62 mm.; long. 72 mm.; hinge line 40 mm.; diameter 12 mm. 

Thi~ species is similar in general characteristics to tile typical P. estrellanus, 

but differ.s from it in being much flatter, having a relatively much longer hinge, 

and, on the average, more ribs. The characteristic constriction of P. estrellanus 

is also lacking in this variety, so· far as known. 

P. var. catal1.:nce ranges from the upper Miocene to the Pliocene. On Santa 

Catalina Island it is associated with the typical P. estrellanus, in beds which are 

probably upper Miocene, while at Temescal Canyon, near Santa Monica, it is 

associated with the well-known Pliocene species P. stearn8ii, P. cer1•osensis, and 

Laqueus califurnic,us (or j ejfreysi). · 

The type, which is figured and ·is now in the collection of Delos Arnold, was 

found in · a limy matrix near the isthmus, Santa Catalina Island, Los Angeles 

County, by Mr. F. H. Thurston. . 

RANGE. 

Pliocene (lower). Temescal Canyon~ Santa Monica Mountains, Los Angeles County 

(Watts). 

Miocene (upper). Isthmus, Santa Catalina Island, Los Angeles County (Thurston, 

Mrs. Trask);? San Ardo and vicinity, Monterey County (Hamlin, Anderson). 

PECTEN (LYROPECTEN) ESTRELLANUS CONRAD var. TERMINUS n. var. 

Pl. XXIII, figs. 2 and 2a. 

Description.-Shellaveraging about 70 millimeters in altitude, somewhat longer 

than high, ventricose, subequivalve, equilateral; margins coarsely serrate. Right 

valve with about 15 prominent, squarish ribs, separated by narrower channeled 

interspaces, in each of which runs a prominent intercalary; surface of ribs · and 

interspaces obsoletely radially striate; hinge line more than one-hal£ length of disk; 

ears subequal, the anterior strongly radially ribbed, the posterior with finer 

sculpture; byssal notch deep and rather narrow. Left valve similar to right, except 

that the ribs are relatively narrower. 

Dirnension8.-Alt. 70 mm.; long. 75 mtn.; hinge line 43 mm.; diameter 32 mm: 

This variety is distinguishable from the typical form by its fewer and broader 

ribs, relatively longer hinge line, and finer obsolete radial striation; and from var. 

atalin ce by its fewer ribs and greater convexity. · · 

The type of P. var. terminu8 is from the upper Miocene or San Pablo horizon 

of Monterey County, and is now in the collection of -the University of California. 

RANGE. 

Miocene (upper). Monterey County (University of California). 

PECTEN (LYROPECTEN) MAGNOLIA Conrad. 

Pl. XXIV, figs. 1 and 2; Pl, XXV, fig. 1. 

1857. Pecten magnolia Conrad, Pae. R. R. Rept., vol. 7, 1857, p. 191, pl. 1, fig. 2. 

1888. L iropecten veatchii Cooper (not of Gabb ), Seventh An.n. Rept. Cal. St. Min., 1888, p. 246 

("Pliocene, Ojai Valley"). 

1898. Pecten magnolia Conrad, Dall, Trans. Wagner Free lust. Sci., vol. 3, pt. 4, 1898, p. 702 (in part). 

1901. Pecten magnolia Dall, Nautilus, vol. 14, 1901, p. 117 (in part.) ' 

. \ 
78 TER:iA~Y AND QUATER~ ARY PECTENS OF _CALIFORNIA. · 

. . 

Descri_ption.~Shell averaging about 150 millimeters in altitPde, slightly lm)ger 

than high, subequivalve, equilateral, rather thick; somewhat ventricose, and with 

smooth margins; · base regularly rounded; sides sloping above, and slightly concave. 

Right valve slightly more convex than left, with about 9 to 11 broad·, flat-topped, 

equal, equidistant .ribs; intersplces slightly narrower than ribs and flat-bottomed; 

whole surface of ribs -and interspaces covered by imbricated radiating riblets (about . 

10 on each rib) . and fine, concentric incremental lines; hinge line about two-thirds 

the length of the disk; ~nterior ear slightly longer than the. posterior, with arcuate 

end and fine concentric increinental sculpture; but obsolete radiatin.g ridges; posterior 

ear with no radial scul'ptui·e what.ever; byssal •notch I:elatively small. Left valve 

quite similar to right but with' narrower, more ·rounded: ribs; -sculpture of radiating 

riblets and fine wavy incremental lines; . i~terspaces broader than in right valve; 

ears almost · identical to those of right. ·. 

-'Dimensions.-Alt. 146 nim;; long. 150 mm.; hinge line· 105 inm.; diameter 

65mm. · · 

The original_-description and figure of this species are poor,' but there is no 

question in the writer's mind as to which species Corirad applied ·this name. There 

is no other large Pecten in the Miocene of the West Coast having th~ small number 

and characteristically large, striate ribs,' and ears with so little radiate sculptur~. 

The figure of the type, .. poor as it is, shows that there was ·little or no radiate 

sculpture on · the ear~ of .the -specimen or specimens servirig as the type for the 

drawings. Furthermore, there is no ·other . Pecten, except · the species ·above 

described, which would bring out the following comment, which . Conrad, in his 

original description, applied to _F. magnolia: 

"This species will compare in size with P. Jejfersonius 'Say, and 'is so remarkably -similar to i.t that it may prove .to be the same species when more perfect· specimens are collected." 

The specimens which . serv~d as the _types for Conrad's P. magnolia are . in .the 

U. S. National Museum (Nos. _13311 a~d 13325)", and came £ron1 _ the Santa. Inez 

Mountains, Santa Barbara County. Although much broken, these specimens show 

the ribbing and sculpture of the original shell almost perfectly; 

In many of the worn specime·ns of this species the radiating strire have been 

lost, and the . ribs . appear smooth. Internal casts sho.w smooth rounded ribs fop 

both· valves. The distinguishing ·characteristics of this magnificent _species, some 

of which attain an altitude o~ over 210 millimeterE!, are its. size, small _number and 

~quality .of ribs, equality of ears, and almost total lack of any radiating: sculpture 

.on the ears. . 

.P. magnolia is somewhat closely ·allied .to P. arassica?f'do, and is no doubt its 

precursor. It is distinguishable from the latter by its fewer (9 to 11, instead of 

14 to 17),-broader, more square-cut and more coarsely radially sculptured ribs, and 

the obsolete radia~ sculpture on its ears. - . · 

P. magnolia. is one of _ the most. characteristic of the lower Miocene, or V .aqu.eros 

formation, fo.ssils: ·. In the region around Mind ego Hiil, San Mateo County, it is 

found in the Vaqueros sandstene- assoCiated _ with _the . following fauna: Agasorna 

barkerianum, Aqasom.a (cf.). g1'avid~, Agasoma kernianum, Area (cf.) microdonta; 

I , 
MIOCENE PECTENS. 79 

Balanus (cf.) estrellantt8, Cardiun1 (Trachycardium) n. sp., Chione mathewsom i, 

Cltione n. sp. (large; coarse sculpture), Crep1~dula princeps, Cuma biplicata, Dosin1:a 

conradi, Dos1:nia nwthewsonii, Dosinia (cf.) montana, Dosinia (aff.) ponderosa, Galerus (aff.) eccentricus, Glycymeris n. sp. (large), Plwcoides .zcutitineatus, Phacoides 

richtlwfeni, Hytilus mathewsonii, JYeverita recluziana, Ostrea (a .if) titan, Panopea 

generosa, Pecten estrellanus, P ecten (Plag.ioctenium) andersoni, Solen sicar£us, Tivela 

ineziana, Trochita costellata, Tur1·itella hojfmanni. On the south fork of the lower 

Ojai Valley, Ventura County, Mr. Eldridge found P. magnolia associated with 

Chione n. sp. (large; coarse sculpture), Hytilus mathewsonii, Turritella lwifmann,£, 

Pecten sespeensis var. hydei, and other lower Miocene forms. 

RANGE. 

Miocene (lower). Mindego Creek, 10 miles south of Stanford University (Arnold)~ 

Corral de Piedra Creek, San Luis Obispo County (J. H. Wilson; Robert Moran; 

Fairbanks); Hazard Canyon, 12 miles south~est of San Luis Obispo (N. H. 

Drake); Morro and Toro creeks, San Luis Obispo County (Fairbanks; R. 

Moran); Santa Inez Mountains, Santa Barbara County (Conrad); near Oceanic 

quicksilver mine, San Simeon, San Luis Obispo County (L. Wagner); Ojai 

Valley, Ventura County (Eldridge). 

PECTEN (LYROPECTEN) MIGUELENSIS n. sp. 

Pl. XXII, £gs. 1, la, and lb; Pl. XXIII, £g. 1. 

1898. Pecten (Lyropecten) Heermanni Dall, (not Conrad), Trans. Wagner Free Inst. Sci., vol. 3, pl. 4, p. 

701. (Specimens in U. S. Nat. Mus., No. 6397, labeled P. Heermanni by Conrad; Pl. XXIII, 

fig. 1. ) 

Description.-Shell averaging about 110 millimeters in altitude, about as long as 

high, ineqnivalve, subequilateral, rather thin, and with margins more or less serrate; 

base rounded; sides slightly concave above, the posterior being slightly longer than · 

the anterior. .Right valve more convex than the left, with 17 •or 18 prominent 

rounded ribs, each sculptured by several (10 or 11 at extremity of ribs in type) dis- · 

tinct radiating raised riblets and numerous sharp, minutely wavy, incremental lines; 

interspaces narrower than ribs, and containing by a prominent radial auxiliary rib, 

which is ornamented by the incremental sculpture, and toward the periphery of the 

disk, by two or more radiating riblets as in the large ribs; hinge line somewhat 

longer than one-half the length of the disk; anterior ear arcuate in front, with small 

byssal notch, and sculptured by 5 or 6 prominent, rounded, radiating ridges and 

numerous sharp, concentric lines; posterior ear with 10 .or 11 radiating riblets and 

fine incremental sculpture. Left valve less ventricose than the right, but otherwise 

similar to it, except that the ribs are slightly narrower and the interspaces relatively 

broader; ears similar to those of the right valve except that the anterior one lacks 

the byssal notch . 

.Dimensions.-Alt. 107 mm.; long. 110 mm.; hinge line 60 mm.; diameter 50 mm. 

This species is distinguishable from P. estrellanus and others of the same group 

by its larger size, inequality of valves (which are more or less inequilateral), and 

radially striate surface from umbo to periphery. It sometimes shows the constric-
80 TERTIARY AND QUA TERNARY PECTENS OF CALIFORNIA. 

tions common to P . . estrellanus. 1 ). miguelensis may be the P. · catilliformis of 

Conrad (Pac. R. R. Rept., Vol. V, Pt. II, p. 83, Pl. IX, fig. 83, 1857}, but his 

description is so brief and his figure so poor that it is impossible to make anything 

definite out of it. · 

P. mig1telensis is confined to. the Miocene (probably lower horizon). 

The type is a slightly crushed specimen from San . Miguel Island. · It is the 

. specimen figured, and is now in the collection of the University of California. 

RANGE. 

Miocene. San Miguel Island (Univ. ofCal.); Santa Rosa Island (No. 12333, Cal. St. 

Min. Bureau); Santa Inez Valley, near Santa Barbara {J. H. Wilson); Santa Inez 

Mountains, near Santa Barbara, Santa Barbara County (Pac. R. R. Expedition). · 

PECTEN (LYROPECTEN) PERRIN! n. sp . . 

/ 

Pl. XIV, figs. 1 and la; Pl. XV, fig. 1. 

.Description.-Shell averagii;lg about 150 millimeters in altitude, somewhat 

longer than high, inequivalve, equilateral, of medium thickness, ventricose, and 

with smooth margins; base regularly rounded; sides sloping - and decidedly 

concave above: Right valve nearly flat, w'ith about 23 unequal, . narrow, more 

or less rounded, and often prominently imbricated, ra.diating ribs, . which are 

sometimes dichotomous; interspaces unequal, narrow, and ·occasionally ornamented 

by a small auxiliary riblet; surface sculptured by fine incremental lamellre 

which are much more prominent in some specimens than in others; hinge line 

about . one-half length · of disk; ears about equal in length; anterior ear wide, 

ornamented by concentric incremental sculpture; byssal notch wide and deep; 

posterior ear ornamented · by several prominent, more or less imbricated radiating 

ridges, and concentric sculpture. Left valve quite prominently ventricose, otherwise similar to the right, e~cept that the ribs seem to vary even more in 

relative size and , spacing; anterior ear lacking · notch, otherwise ears similar to 

those of the right valve. 

Dimensions.-Alt. 150 mm.; long. (restored) 160 mm.; hinge line (r-estored) 

80 mm.; diameter 55. mm . 

. This is a most variable species, there being no two specimens sculptured 

in exactly . the same manner in a series of over fifty specimens examined. · The · 

convexity of the valves is almost cbnstant, the variable factors being the number 

and ' relative importance ·of the intercalary ribs, and the prominence of the · 

incremental sculpture. • 

The geologic range of P. perrini is from the lower to the middle ( ?) 

Miocene. It is found associated with Pecten magnolia, and other characteristic 

lo~er Miocene fossils between Morro and Toro creeks, San Luis Obispo County, 

while at Roblar, in the same county, it is found with P. disc,us, a species found 

usually in the Santa Margarita formation. · 

The type, an imperfect specimen, of which both valves are figured, is from 

the lower Miocene between Morro and Toro creeks, San Luis Obispo County, 
MIOCENE PECTENS. 81 

and is now in the collection of the department of geology, Stanford Univers~ty. 

Named in honor of Dr. James Perrin Smith, professor of paleontology at the 

Leland Stanford Junior University. 

Miocene (middlen. 

Gillis, 10 miles 

Smith). 

RANGE. 

Roblar, 1~ miles from Paso Robles, and on ranch of W. F. 

southwest of Paso Robles, San Luis Obispo County (J. P. 

Miocene (lower). Between Morro and Toro creeks, and on the Lenton ranch, 

between Morro and Old creeks, San Luis Obispo County (Fairbanks, R. 

Moran)~ 30 miles north of Santa Monica and 1 mile from the ocean, 

Ventura(?) County (R. E. Maynard); Pyramid Mountain, Greenhorn Mountains, Kern County (No. 12925, C. S. M. B.) (Watts). 

PECTEN (LYROPECTEN) VAUGHAN! n. sp. 

Pl. XXIII, figs. 3, 3a, and 3b. 

Descr1]Jtion.-Shel1 averaging a bout 40 millimeters in altitude, slightly longer 

than high, inequivalve, equilateral, convex, and showing constrictions with 

consequent undulations on the right valve and nodose ribs on the · left; base 

regularly rounded; sides nearly straight above; margins smooth. Right valve 

with 12 prominent convex ribs separated by concave-bottomed interspaces somewhat narrower than the ribs; surface of ribs and interspaces sculptured by 

numerous fine, imbricated, thread-like, radial lines, between which are fine 

imbricating concentric line., the lines multiplying by intercalation toward the 

periphery of the disk~ hinge line about five-eighths length of disk; ears unequal, 

the anterior much elongated, rather narrow, and ornamented by 4 very 

prominent, rounded, sharply imbricated radials and numerous fine imbricating 

incremental lirro; byssal notch deep; posterior ear about one-half length of 

anterior, somewhat concave behind, and ornamented by about 6 radial and 

numerous fine incremental lirro. Left valve similar to right, but with narrower, 

sharper ribs and correspondingly broader interspaces; the second, fourth, seventh, 

tenth, and twelfth ribs from the posterior ·end are more prominent than the 

others, and are subnodose at the lines of undulation of the disk; anterior ear 

similar to that of the right valve but with 2 or 3 more radials, which are less 

prominent; posterior ear like that of right. 

Dimensions.-Alt. 37 mm.; long. 40 mm.; hinge line about 25 mm.; diameter 

15 mm. 

This beautiful little Pecten, though allied to P. magnolia, P. crassica,rdo, etc., 

is distinguishable by its small size, obviously unequal ears, long and strongly 

radially sculptured right anterior ear, deep byssal notch, undulating disk, and 

finely striated, concave-bottomed interspaces. This form seems to combine the 

number of ribs of P. magnolia (P. magnolia generally has one to three less), 

with the sculpture of P. crassicardo var. l~a'fniltoni, the undulations of P. crassicardo, and the long, strongly sculptured, right anterior ear of the typical Ohlamys. 

It appears to be a connecting link between the (ypical Ohlamys and Lyropecten. 

17260-No. 47-06-6 
82 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

The range of this species is not definitely known. It is found In the 

Miocene, probably lower, of the Ojai Valley, Ventura County. The type, which 

was collected at the above locality by Dr. Stephen Bowers, is now in the 

collection of Delos Arnold. The species is named in honor of Dr. T. Wayla!J.d 

Vaughan, of the United States Geological Survey. 

RANGE. 

lYliocene (lower). Ojai Vall"ey, Ventura County (Bowers). 

PECTEN (PLAGIOCTENIUM) ANDERSON! n. sp. 

Pl. XXVI, figs. 5, 5a, 6, 7, 8, and Sa. 

J894. Pecten discus Cooper (not Conrad), Bull. Cal. St. Min. Bureau, No. 4, pt. 5, 1894, p. 57, pl. 5, 

figs. 55 and 56 (in part). 

Description.-Shell averaging about 35 millimeters in altitude, generally somewhat longer than high, both valves convex, more or less inequivalve and inequilateral; margins smooth; base regularly rounded; sides concave above. Right 

valve with 14 to 18 prominent rounded ribs, separated by flat-bottomed interspaces, which are generally of about equal width to, but sometimes narrower than, 

the ribs; surface sculptured by numerous, sharp, imbricating, incremental lines, 

and sometimes, at irregular intervals, by more or less prominent lines of interrupted growth; hinge line more than one-half length of disk; ears subequal; 

anterior ear with 3 or 4 sharp radials and numerous :fine concentric lines; 

byssal notch quite pronounced; posterior ear sculptured similarly to anterior, and 

truncated nearly rectangularly. Left valve more convex than the right, scu~ptured 

similarly and with similar ears, except that the notch in the anterior is not so 

pronounced. 

Dimensions.-Alt." 37 mm.; long .. 44 mm.; hinge line 23 mm.; diameter about 

8 mm.; umbonal angle 105° . 

A prominent oharacteristic of this species is that the _left is decidedly the 

more convex of the two valves. In this respect it is similar to P. latiauritus 

and varieties. In fact, the young of P. andersoni is almost indistinguishable, in 

some instances, from· small specimens of P. latiaurwus var. monotimeris. The 

young of P. andersoni are equilateral, are relatively more convex, and have more 

prominent ribs than the adult forms. · 

Those specimens of P. andersoni found in the earlier formations appear to 

' be somewhat smaller, and have on an average fewer ribs (14 to 17) than those in 

the later Miocene horizons, which have from 15 to 18. Exceptions to this rule, 

however, are not rare, one specimen, for example, from the same locality as the 

type (which has 16 ribs . on the left valve) having 18 ribs. 

It would not be surprising to the writer to find, after an examination of a 

large series of P .. andersoni and allied forms from the upper Miocene, that it is 

more or less closely related to P. discus. Large specimens of P. andersoni very 

closely resemble some specimens of P. discus but differ from the latter in the 

fewer number (14 to 18) of their ribs, P. discus having 18 to 21. 
MIOCENE PECTENS. 83 

]"">. andersoni ranges from the lower to the middle (and probably upper) 

Miocene. At locality No. 9 (L. S. J. U. Geol. Survey), on "Tuff Hill," 3t miles 

southeast of Stanford University, P. andersoni is associated with the following 

species: P ecten branneri, Chione n. sp., Phacoides acutilineatus, Venus (cf.)pertenuis, 

Terebratella ( ?) n. sp., Glycymeris sp., and Balanus sp. (if.) estrellanus. At 

locality No. 4, not far from but stratigraphically considerably above No. 9, we 

find P. andersoni with the the following: Agasoma barkerianum, Area .n?..im·odonta, 

Chione sp., Callista n. sp. A., Dosinia matlwwsonii, L eda ( cf.) taphria, Phacoides 

acutilineatus, J1factra californica, Natica ocoyana (?), Saxidomus gibbos~ts, Tapes . 

truncata ( ?), Trochitct costellata, Tellina ( Angul us) sp., Tritonium sp., Tivela 

ineziana, and Yoldia n. sp. ( aff.) cooperi. On the Sears ville road, 3t miles west 

of Stanford University (locality 2), P. andersoni is associated with the following 

among other species: Agasoma gravida, Agasoma kernianum, . Dosinia (a if.) 

ponderosa, and Pinna alamedensis. At Barker's ranch, Kern County, Mr. Watts 

found P. andersoni associated with Agasoma barkerianum and kernianum and 

other supposedly characteristic lower Miocene forms. P. andersoni occurs with 

P. crassicardo in the upper Miocene 3 miles south of Mount Diablo. In Avenal 

Canyon, Kern County, P. andersoni is associated with P. andersoni var. barkerianus, 

Turritella ocoyanct, Venus sp., Ostrea sp., and a large flat Dosinia. In the Devils 

Den country, Kern County, P. andersoni is found with P. crassicardo in beds of 

probable lower Miocene (Vaqueros) . age. 

The type of P. andm·soni, which is now in the collection of the department of 

geology, Stanford University, is from locality 127, three-fourths mile below Zayante 

station on Zayante Creek, Santa Cruz County, where it was found associated with 

P. sespeensis var. hydei and Balanus (cf.) estrellanus. The beds from which the 

type was taken lie only ~L few feet below, and conformable with, the base of the 

characteristic Monterey shales, which are very well developed in the vicinity. 

RANGE. 

Miocene (upper). Three miles south of Mount Diablo, Contra Costa County 

(University of California); Pacheco, Contra Costa County (J. p, Smith); San 

Pablo Bay, near Pinole, Contra Costa County (Merriam, Arnold). 

Miocene (middle and lower). Locality 127, Zayante Creek, three-fourths mile below 

Zayante station; near Glenwood (Miss Hecox); near :Magnetic Springs; near 

Felton (locality 32), Santa Cruz Count}7 ; near Stanford University, at localities 

1, 2, 3, 4, 9, 34, and 35, Santa Clara and San Mateo counties (Branner, J. P. 

Smith, Arnold, and others); Barker ranch, Kern County (Watts); New Almaden 

(Turner); Contra Costa County (Lawson); near head of Slacks Canyon, NE. t 

sec. 9, T. 22 S., R. 13 E., Mount Diablo meridian, Monterey County (Hamlin); 

Avenal Canyon, Kern County (Eldridge); Devils Den, Kern County (Eldridge). 

PECTEN (PLAGIOCTENIUM) ANDERSON! var. BARKERIANUS n. var. 

Pl. XXVI, fig: 9. 

Description.-Sbell averaging about 40 millimeters in altitude, somewhat longer 

than high, equilateral, somewhat ventricose, and with serrate margins; base regu-
84 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

larly rounded; sides nearly straight, sloping at a moderately low angle. Left valve 

with 17 rather narrow, prominent rounded ribs, each with a rounded, thread-like 

rib let running longitudinally along its top; , at more or less regular intervals small 

obsolete spines protrude from the riblet; interspaces wider than the ribs, with 

sloping sides, and flat bottoms; ·whole surface of disk crossed by very fine incremental 

lines; hinge line longer than one-h~lf length of disk; ears subequal, reCtangularly 

truncated, and sculptured by radiating ridges and incremental lines. 

Dimensions.-Alt. 40 mm.; long. 44 mm.; hinge line 28 mm.; diameter 7 mm. 

This variety, which is characterized by the thread-like riblet alo~g the top of 

each primary rib on the left valve, has been found only in beds of lower Miocene 

age (Turritella ocoyana zone) in the southern San Joaquin country. It is found 

associated with the following characteristic fauna in the bluffs of the Kern River, 

1 mile below the power-developme~t station, Kern County: Conus n. sp., Mactra 

near JJlanulata, Phacoides sp., Tellina near idee, Trochita filosa, Agasoma kernianum, Agasoma barkerianum, Leda taphria, Leda (aff.) fossa, · Cancellar1:a n. sp., 

Pleurotoma (Doliclwtoma) n. sp., Pleurotoma (Leucosyrinx) near- pedroana, Chione 

n. sp. near gnidia, D entalium 2 n. sp., Nassa ( cf.) perpinguis, Ple·urotoma sp., 

NejJtunecb n. sp., Crucibulum n. sp., Turritella ocayana, Cancellaria ( cf.) vetusta, 

Phacoides (qf.) nuttalli, Natica or Lunatia sp., Terebra sp. (probably new), Trophon 

(cf.) JJOnderosum, Drillia (ajf.) torosa, Solen (atf.) sica1·ius. At Avenal Canyon, 

Kern County, Mr. Eldridge found P. var. barkerianus with P. andersoni, Turritella 

ocoyana, Dosinia (large and flat), Venus sp., and Ostrea sp. 

The type of P. var. , barkerianus was found east of the Barker ranch house, 

near Kern River, Kern County, and IS now Ill the collection of the California 

Academy of Sciences. 

RANGE, 

Miocene (lower). Barker ranch, Kern County (Watts): Avenal Canyon and bluffs 

of Kern River near power-development station, Kern County (Eldridge). 

PECTEN (PLAGIOCTENIUl\1) CERROSENSIS GABB var. ~ MENDENHALL! n. va:r:. 

Pl. XXV, figs. 2, 2a., and 2b. 

Descrpt1:on.-Shell, when adult, averaging about 75 millimeters in altitude. 

Similar to P. cerrosensis in shape, convexity, and ribbing, but differing from the 

latter in being much smaller when adult, having fewer ribs (about 19 in the former, 

while the latter has usually 21 or more), much less prominent incremental lines, 

and a relatively longer hinge line. 

Dimensions (of a medium-sized specimen).-A1t. 43 mm.; long. 44 mm.; hinge 

line 28 mm. ; diamet~r 17 mm. 

Although this 'form is plosely allied to P. cerrosens~s, it, nevertheless, should 

possibly have specific rank, as the differences between it and the typical P. cerrosensis 

are constant, and it belongs· to a different geologic horizon. Not enough is known 

about its range and relations, however, to warrant a wider separation, at present, 

than that of a variety. 

The type is from beds of probable Miocene age (the equivalent of the Carrizo 

Creek beds) at Santa Rosalia, Lower California, directly west of and across the Gulf 
MIOCENE PECTENS. 85 

of California from Guaymas, Mexico. At the type locality it is associated with 

the following fauna: Pecten carrizoensis, Pecten keepi, Oardittm sp., Chione n. sp., 

Glycyrneris sp., Ostrea sp. (large), Oodakia sp. (very large), Semele (aff.) pulchra, 

Oardita ( Oarditarnera) sp., Strornbus sp., Malea (ajf.) ring ens, echinoid spines, etc. 

The type of P. var. rnendenhalli is U. S. N. M. No. 164849, and is from Santa 

Rosalia, Lower California, where it was collected by Doctor J\'lerrill. Named in 

honor of Mr. Walter C. Mendenhall, of the United States Geological Survey. 

RANGE. 

Miocene. Santa Rosalia, Lower California (G. P. Merrill; E. Palmer); head of 

Garnet Canyon, about 12 miles north of the .Mexican boundary, and Alverson 

Canyon, about 8 miles north of the Mexican boundary, San Diego County 

(W. C. Mendenhall; S. Bowers). 

PECTEN (PLAGIOCTENIU:lVI) DESERT! Conrad. 

Pl. XXVI, figs. 1, 2, 2a, 3, 4, and 4a . . 1855. Pecten deserti Conrad, Desc. Fos. and Shells., House Doc., 129, July, 1855, p. 15 (fide Dall) . 

1856. Pecten deserti Conrad, Pac. R. R. Rept., vol. 5, 1856, p. 325, pl. 5, fig. 41. 

1888. Pecten deserti Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., for 1887, p. 257. 

1894. Pecten ( Plagioctenium) deserti Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, 

p. 703. 

Description.-Shell averaging about 32 millimeters in altitude, about as long as 

high, biconvex, equivalve, subequilateral, and with serrate margins; sides straight 

and sloping at a steep angle. Right valve with 22 or 23 high, narrow, close-set, 

smooth, rounded ribs, which sometimes show looped incremental lines on their 

tops near extremities; interspaces deep, narrow, slightly concave bottomed, and 

ornamented on the bottom by numerous fine, sharp, straight, incremental lines; 

hinge line about three-fourths length of disk; ears subequal; the anterior slightly 

convex and ornamented by 4 radiating ridges and numerous incremental lines, 

while the posterior is ornamented by 6 or 7 radials and numerous concentric 

lines; byssal notch rather small. Left valve similar to the right, except possibly 

that the ribs are relatively slightly taller. Hinge strong, with a deep resilial pit 

and a submarginal channel parallel with the upper margin; numerous parallel 

microscopic lines perpendieular to the hinge line visible in the crural grooves. 

Dimensions.-Alt. 32 mm.; long. 33 mm.; hinge line 25 mm.; diameter 17 mm. 

This species is distinguishable from allied forms by its strong hinge, tall, 

narrow, close-set ridges and straight incremental sculpture in the bottoms of the 

interspaces. 

P. deserti has so far been found only in beds supposed to be of Miocene age, 

in the Carrizo Creek district, Colorado Desert, San Diego County. From the 

evidence at hand it seems likely that P. deserti occupies a somewhat different 

horizon (possibly lower) than that containing P. carrizoensis, P. keepi, and P. 

cerrosensis var. rnendenhalli. RANGE. 

Miocene. East end of Carrizo Mountain, and Ulsa oil well, north of the Mexican 

boundary, San Diego County (Conrad; Fairbanks; Bowers; Mendenhall). 
86 TERTIARY AND QU.ATERN ARY PECTENS OF CALIFORNIA. 

PECTEN (PLAGIOCTENIUM) DISCUS Conrad. 

Pl. XXVII, figs. 1, 1a, 2, 3, find 4. 

· 1857. Pecten discus Conrad, Pac. R. R. Rept., vol. 7, pt. 2, 1857, p. 190, pl. 3, fig. 1. 

1869. Pecten discus Conrad, Gabb, Pal. Cal., vol. 2, 1869, p. 122. 

1888. Pecten discus Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 257. · 

1888. Pecten pabloensis Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 258 (in part). 

1894. Not Pect n discus Cooper, Bull. Cal. St. Min. Bureau, No. 4, pt. 5, 1894, p. 57, pl. 5, figs. 55, 56. 

( = P. andersoni n. sp.) · 

1898. Pecten ( Chlamys?) discus Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. .3, pt. 4, 1898, p. 704. 

Description.-Shell averaging about 50 millimeters in altitude, about as long 

as high, equivalve, equilateral, thin, rather compressed) and with smooth margins; 

umbonal angle large, averaging about 108° ; sides somewhat concave above. Rigli:t 

valve with 17 to 20 moderately strong, rounded ribs, separated by rather flat 

interspaces about equal in width to the ribs; surface sculptured by regular, 

elevated, wavy, incremental lines and, at irregular intervals, generally by more 

or less prominent lines of interrupted growth; hinge line about one-half length 

of disk; ears unequal, the' anterior showing several strong radials, while on the 

posterior the radials, are obsolete; both ears sculptured by fine concentric lines. 

Left valve similar to right; ears more or less distinctly radially ridged and 

obliquely truncated. . 

Dimensions.-Alt. 48 mm.;, long. 50 mm.; hinge line 24 mm.; diameter 8 mm.; 

umbonal angle 108° . 

This species, of which the type is a poor specimen, being preserved as a cast in 

indurated clay, is characterized by its moderately strong, convex ribs, compressed 

disk, and st\·ikingly unequal ears on the right valve. . Specimens of P. discus having 

.the shell material preserved always show moderately high, convex ribs; the internal 

casts (in which form the species is generally found) have the ribs more or less 

squarish, and low. The specimens having the fewest number of ribs have the widest 

lateral areas or submargins. The type does not show the radial sculpture found in 

most cases on the ears of the left valve. 

P. d1:scus is closely allied to P. pabloensis but has the constant difference of 

larger size when adult and stronger rounded ribs instead of weak squarish ones. It 

occurs in approximately the same horizon as P. pabloensis and seems to represent the 

latter in what is probably the equivalent of the San Pablo (upper Miocene) formation in the region south of the typical San Pablo Bay locality, although at some 

localities it has been found in beds of probable middle Miocene age. 

About the head of Crescent Creek, . near Oil City, Fresno County, P. discus is 

associated with the following: Ocinebra, near cancellina, Trockita filosa, .Mytilu..<: 

mathewsonii (~),Area sp. indet., and Volttta 0) sp. This appears to be an uncertain 

horizon in the Miocene. 

. RANGE. 

Miocene (upper). Walnut Creek, Contra Costa County (Univ. of Cal. collection); 

Santa Margarita, San Luis Obispo County (J. H. Henry); Assuncion ranch, San 

Luis Obispo County (Fairbanks; Arnold; R. Moran); Huasua ranch, ~0 miles 

north of Santa Maria, Santa Barbara County (C. E. Knecht). 
MIOCENE PEC'.rENS. 87 

Miocene (middle or lower?) Roblar, 12 miles from Paso Robles, and on ranch of 

W. F. Gillis, 10 miles southwest of Paso Robles, San Luis Obispo County (J. P. 

Smith); Oil City, Fresno County (Eldridge). · 

PECTEN (PLAGIOCTENIUM) ELDRIDGE! n. sp. 

Pl. XXV, figs. 3, 3a, 3b, 4, 4a, 5, 5a, and 6. 

Description.-Shell averaging about 20 millimeters in altitude, nearly as high 

as long, equivalve, somewhat oblique (the posterior portion being the longer), very 

thick and heavy, very ventricose, and with serrate margins; base unequally 

rounded; sides somewhat concave above and sloping at a moderately steep angle. 

Right valve with 19 or 20 small, rather low but sharply defined, squarish ribs; 

interspaces about one-half as wide as ribs, channeled, and with flat bottoms; 

surface of disk ornamented by numerous sharp concentric lines which loop back 

over the ribs; more or less prominent constrictions, indicating interrupted growth, 

are common on most specimens; hinge line eql;(al to about three-fourths length 

of disk; anterior ear slightly longer than posterior, deeply notched, and ornamented by 3 or 4 prominent radiating ridges and numerous imbricating incremental lines; posterior ear rectangularly truncated and ornamented by 8 or 10 

radiating ridges and incremental sculpture. Left valve similar to right, except 

that the ribs are slightly narrower and more rounded; ears similar to those of 

right valve except that the anterior one is not as deeply notched. Hinge similar 

to that of P. circularis except stronger and with the auricular crura much more 

highly developed. Adductor impressions very deep. 

Dimensions.-Alt. 20 mm.; long. 21 mm.; hinge line 15 mm.; diameter 15 mm. 

This species is similar in many respects to P. circularis, but is characterized 

by its smaller size, greater ventricosity, thicker and heavier shell, deep adductor . 

impressions, and more or less prominent constrictions. It sometimes attains an 

altitude of 45 millimeters, as shown by fragments collected at the type locality. 

Ij. eldridgei appears to be confined to the oil-bearing strata of the San 

Joaquin Valley, which are probably San Pablo or upper Miocene in age. 

The type, which is figured and is now in the United States National Museum, 

was collected in the hills south of the Dabney water wells, McKittrick district, Kern 

County. Named in honor of the late Mr. G. H. Eldridge, of the United States 

Geological Survey. RANGE. 

Miocene (upper). McKittrick district, Kern County (Eldridge); Buena Vista and 

McKittrick, Kern County (Watts). 

PECTEN (PLAGIOCTENIUM) NEAHENSIS n. sp. 

Pl. XV, figs. 2, 2a and 2b. 

Descript1:on.-Adult shell averaging about 45 millimeters in altitude, somewhat 

longer than high, subequivalve, suhequilateral, prominently ventricose, especially 

for about the first. 25 millimeters of altitude, after which it is sometimes more 

compressed; sides concave above; base evenly rounded; margins smooth. Right 

valve with 19 prominent rounded ribs, separated by somewhat · narrower 
88 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

interspaces; surface sculptured by flue incremental lirulre which loop back over · 

the tops of the ribs; hinge line over one-half length of disk; ears subequal; 

anterior with 4 or 5 prominent radials, posterior with one or two less prominent 

ones; ' both ears sculptured by fine incremental lines; byssal notch rather 

prominent. Left valve a little less ventricose. than right and with ribs narrower 

ftnd more sharply convex above and the interspaces relatively broader; ears as 

in right valve. 

Di,mensions.-Alt. 43 mm.; long. 50 mm.; hinge line 28 mm.; diameter 

28 mm. 

This species is probably allied to .P. eircularis and P. circularis var. 

requisulcatus, but may be distinguished by its fewer and narrower ·ribs and longer 

hinge line. 

The type (U. S. N. M. No. 5912) is labeled "Neah Bay, Washington," and 

was collected by Lieut. J. G. Swan. The b.eds in the immediate vicinity of 

N eah Bay were found by the writer to be almost entirely unfossiliferous, so that 

it is. probable that P. neahensis, instead of coming from Neah Bay, comes from 

some of the fossiliferous strata farther east, possibly from those in the vicinity 

of Clallam Bay. 

RANGE. 

Miocene. Clallam County, near 0) Neah Bay, Washington (J. G. Swan). 

PECTEN (PLAGIOCTENIUM) PABLOENSIS Conrad. 

Pl. XXVII, figs. 5, 5a, q, 6a, and 7. 

1857. Pecten pabloensis Conrad, Pac. R. R. Rept., vol. 6, pt. 2, 1857, p. 71, pl. 3, fig. 14. 

1888. Pecten pabloen8is Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 258 (in part). 

1898. Pecten (? Plagioctenium) pabloensis Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 

1898, p. 703. 

Description.-Shell averaging about 35 millimeters in altitude, about as high 

as long, equivalve, equilateral, thin, only slightly ventricose, and with smooth 

margins; sides sloping at a low angle and quite prominently concave above: 

Right valve with 18 to 20 square, flat-topped, radiating ribs, which are narrower 

and less distinct laterally and become 'more feeble as the periphery of the disk 

is approached; interspaces about as wide as the ribs, flat bottomed and often 

separated from the principal ribs by impressed lines which give the interspaces 

the appearance of bearing intercalary rib lets; whole · surface of disk sculptured by 

fine concentric lines and, in some instances, more or less prominent lines showing 

interrupted growth; hinge line somewhat longer than one-half length of disk; 

anterior ear slightly longer than posterior, deeply notched, and ornamented by 

4 or 5 coarse radiating ridges and sharp, raised incremental lines; posterior ear 

slightly concave behind, and covered by numerous incremental lines and several 

obsolete radiating ribs. Left valve similar to the right except that in some cases the 

ribs are slightly more rounded above, and the looped or wavy concentric lines 

are more conspicuous; ears similar to those of the right .. valve except that the 

anterior one lacks the deep byssal notch. Hinge as in P. circularis except that 

the cardinal crura are very faint, while the auricular crura are quite prominent. 

• 
MIOCENE PECTENS. 

Dimensions.-Alt. 35 mm.; long. 35 mm.; hinge line 20 mm.; diameter 6 mm. 

The measurements given above are from an average-sized specimen. One left 

valve examined was 50 millimeters in altitude, but this size is exceptional for 

specimens from the type locality (shore of San Pablo Bay). 

The prominence of the ribs seems to be the most variable fac.tor in this 

species. As a rule the ribs are sharp and well defined until the shell attains an 

altitude of 10 or 15 millimeters, when they broaden out and become low, those 

near the sides almost losing their identity in some specimens. One specimen 

examined retained the elevated and sharply defined ribs up to an altitude of over 

25 millimeters, and very much resembled a young P. circularis var. ceqttisulcahts. 

P. pabloensis is so far known only in the San Pablo, or upper Miocene 

formation. At the type locality, on the shore of San Pablo Bay, Contra Costa 

County, a bed several feet thick is made up almost entirely of valves of this 

species. A.t this locality P. pabloensis is associated with P. crassicardo and 

P. andersoni ( ?). RANGE. 

Miocene (upper). Shores of San Pablo Bay, Contra Costa County (Newberry; 

Merriam; Arnold). 

PECTEN (PSEUDAMUSIUM) LOMPICOENSIS n. sp. 

Pl. XXIII, fig. 5; Pl. XXVII, fig. 8. 

Descrption.-Adult shell averaging about 11 millimeters in altitude, subcircular, inequivalve, · thin, compressed; margins smooth. Right valve ornamented 

externally by numerous sharp, elevated, equal, equidistant, imbricating, concentric 

lamellre; hinge line equal to one-half length of disk; ears unequal; anterior nearly 

twice as long as the posterior, arcuately truncated and sculptured by regular, 

sharp, imbricating, concentric lamellre and 6 or 7 faint radials; posterior ear short, 

somewhat obliquely truncated and sculptured by concentric lamellre; byssal notch 

only faintly indicated. Left valve sculptured by concentric lamellre similar to those 

of the right, and, in addition, having numerous fine radiating strire, which usually 

become obsolete near the periphery in the adult shell; ears similar to those of the 

right valve, except that in the specimens examined no radials were noted on the 

anterior one. Hinge similar to that of P. randolphi. 

Dimensions (of slightly distorted specimen).-Alt. 11.5 mm.; long. 11 mm.; 

hinge line 5. 5 mm. 

This beautiful little Pecten is allied to P. p eckhami, but is distinguishable 

from the latter by its much more prominent and regular concentric lamellre, and 

by its well-defined ears, the anterior one of which on the right valve is relatively 

much shorter and broader than the analogous one in P. pecklwm.i. The byssal 

notch in P. lompiqoensis is also only faintly indicated, while in I). peckhami the 

notch is profoundly developed. 

P. lompicoensis is known only from the Miocene (exact horizon doubtful) 

shales at the head of Lompico Creek, Santa Cruz County, where it is associated 

with a Phacoides resembling acutilineatus Conrad. 

RANGE. 

Miocene. Head of Lompico Creek, Santa Cruz County (Newsom, Arnold). 
90 TERTIARY AND QUATERNARY .PECTENS 01!' CALIFORNIA. 

PECTEN (PsEUDAMUSIUM) PEDROANUS Trask. 

Pl. XXVIII, :figs. 4 and 5. 

1856. Plagiostoma Pedroana Trask, Proc. Cal. Acad. Nat. Sci., vol. 1, 1856, p. 93, pl. 3, :figs. 1, 1a. 

1856. Plagiostoma truncata Trask, Proc. Cal. Acad. Nat. Sci., V?l. 1, 1856, p. 94, pl. 3, :fig. 3. 

1856. Plagiostoma annulatus Trask, Proc. Cal. Acad. Nat. Sci., vol. 1, 1856, p. 94, pl. 3, :fig. 2. 

1869. Pecten Pedroanus Trask, Gabb, Pal. Cal., vol. 2, 1869, p. 60. 

1888. Pecten p edroanus Trask, Cooper, Seventh Ann. Rept. Cal. St. Min., for 1887, p. 258. 

1898. Pecten pedroanus Trask, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, . p. 705. 

The original description is as follows: 

Description.-" Shell compressed, subtriangular, with 8 or 9 flatly rounded 

concentric an.nulat1ons, which are nearly as distinctly marked on the interior of 

the valve for about half the height from the ventral margin; beaks acute at . the 

apex, and as high as the line of the auricles; anterior auricle rounded in front, 

and has a small, thin fold extending from the umbone to the center of its 

anterior margin, and is covered with about 13 small, rounded, radiating 

strire, which converge at the beak; beaks at the anterior third; subacute; anterior 

margin rounded, and somewhat produced; ventral margin smoothly arched; 

pos.terior margin rounded, becoming slightly arcuate toward the dorsum of the 

shell~ posterior auri'ble angulate and obtusely truncate posteriorly." 

Dim,ensions.-Alt. 30 mm.; long. 37 mm.; hinge line 13.5 mm. 

The above is Doctor Trask's original description with measurements of the 

type. Gahb has the following to say of this species:a 

'' In 1856 Doctor Trask named three species of Plagiostoma, giving full 

descriptions and well-executed figures as above. His specimens are casts of a 

number of distorted Pectens, perhaps normally a little oblique, but in most cases 

with the obliquity exaggerated by pressure. They belong without question to 

but one species, and the first name given will have to be retained. I have 

carefully studied the specimens, and have visited the locality from which they 

were obtained. The deposit belongs to the bituminous shale of the upper Miocene, 

which underlies the whole or the greater part of the Los Angeles plain, crops 

out on the beach at San Pedro, under the post-Pliocene, and has been reached 

by artesian borings under the city itself. 

"'The species is about an inch in diameter, ears subequal, shell thin, perhaps 

normally a little oblique, and the shell substance contains a few concentric 

undulations or ribs, which are retained in the cast. No specimens show any shell 

preserved; so that if there was any surface sculpture, it is as yet unknown." 

The writer has examined several specimens of this species collected by Mr. 

W. L. Watts in the oil fields of southern California. Some of these specimens 

show the original shell material, which, upon a careful examination, revealed no 

trace whatever of any but the concentric undulating sculpture. 

The best preserved specimens of this species examined by the writer were 

taken from the Third street tunnel in Los Angeles by Mr. Homer Hamlin and 

are now in the U. S. National Museum (No. 164840). In several of these specimens 

the original shell material is quite well preserved, and In one case Oamptonectes 

a Pal. Cal., vol. 2, 1869, p. 60. 
MIOCENE PECTENS. 91 

sculpture of numerous faint radiating ribs, microscopic strire, and numerous more 

or less prominent lines of interrupted growth were plainly seen. The sculpture 

was very similar, if not identical, to that of P. randolphi. P. pedroanus and 

P. randolphi are also alike in shape and general characteristics, and the only 

difference noted in a comparison of the two was the slightly larger size and more 

prominently undulated disks of the former. A careful examination of better 

material of the fossil form, if any is ·ever obtained, may lead to a union of the 

two species. 

' The Third street tunnel beds are of soft bluish shale, which yielded besides 

P. pedroantts the following fauna: Pecten ashleyi, P. stearnsii, P. opuntia, Glypltis 

d8nsiclatkrata, Pecten latiaurittts, Nassa n. sp. ~, .iriacoma sp. indet., Area multicostata, Lima lwmlini, Buccinum sp. indet., Neverita reclttziana, A8tarte ~ sp., 

Priene oregonensis, Ostrea veatchi?:, Pleurotoma sp. indet:, carditoid, coral, bird 

hone, and crab claw. ' 

This fauna indicates a horizon about the same as that of the San Diego 

formation, and is Pliocene (probably lower) in age. It therefore seems likely that 

P. pedroanu8, which has heretofore been considered a typical .Monterey or middle 

Miocene species, also occurs in the Pliocene, and may possibly be Dall's recent 

deep-water species, P. randolphi. 

RANGE. 

Pliocene (lower). Clark estate, Los Angeles and Puente Hills, Los Angeles 

County (Watts); Third street tunnel, Los Angeles (Hamlin); Joyce wells, 

Whittier district, Puente Hills, Los Angeles County (Eldridge). 

Miocene. San Pedro (Trask, Gabb); 4 miles south of :McKittrick, Kern County 

(Eldridg·e). 

PECTEN (PROPEAMUSIUM) STANFORDENSIS n. sp. 

Pl. XXIII, fig. 4. 

Description.-Shell averaging· about 9 millimeters in altitude, subcircular, 

equivalve, equilateral, thin, only slightly ventricose, and with smooth margins. 

Right valve with the exterior ;;;urface ornamented by numerous fine concentric 

undulations and, in some cases, microscopic radiating strire; interior with 10 to 

12 prominent, rounded, equidistant ribs extending from the umbo to or near to 

the periphery of the disk, those ribs nearest the · center of the shell being 

straight, while those near the sides are somewhat arcuate toward the central rib; 

hinge line slightly longer than one-half the lengt_h of the disk; ears equal in 

length, and ornamented by the fine concentric undulations; ·anterior ear with a 

small byssal notch. Left valve similar to right, except that its anterior ear lacks 

the byssal notch . 

.Dimensions.-Alt. 7 mm.; long. 7.2 mm.; hinge line 4 mm.; diameter 1.2 mm. 

In the specimens showing the original shell material the internal ribs sometimes break out and leave corresponding grooves in the disk, thus showing that 

they are of a rather secondary growth compared to that of the disk. 

This species is somewhat similar to P. interradiatus of the Tejon (Eocene), 

but may be distinguished from it by having 10 to 12 instead of 8 ribs, being 
92 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

smaller, and having the ribs reach to or nearly to the periphery rather than 

abruptly terminating near the middle of the disk. 

The type specimen, which is the one figured, is now in the collection of 

Delos Arnold. It is from the buff-colored Miocene shale in a small ~avine on 

the Burke ranch, one-third mile south of Los Trancos Creek, near Stanford 

University, San Mateo County. This species . is named in honor of Leland 

Stanford Junior University. 

So far this species 4as been found only in the type locality, where it is 

associated with Pecten pedroanus ( ?) and several small undetermined pelecypods. 

Its range, as determined stratigraphically, isprobably middle Miocene or Monterey. 

Its associated fauna also adds weight to this theory. 

RA:!'IGE. 

Miocene (middle). Burke ranch, 3 miles south of Stanford University (Branner, 

J. P. Smith, R . . Arnold). 

PECTEN (AMUSIUM) LOMPOCENSIS n. sp. 

Pl. XXVIII, figs. 1, 2, and 3. 

Descript~:on.-Adult shell averaging about 100 millimeters in altitude, somewhat 

longer than high, compressed, subequivalve, equilateral, and thin; base regularly 

rounded; sides straight, or nearly so; margins smooth. Right valve with external 

surface smooth except for very fine and numerous concentric and nearl.Y obsolete 

radiating strire; internal surface sculptured by about fourteen pairs of rather 

prominent rounded radiating lirre, the members of each pair being separated by . 

flat spaces usually of about two-thirds the width of the major interspaces (in 

one case the spaces between the members of each pair were as wide as the 

interspaces); hinge line about two-fifths the length of the disk; ears subequal, 

obliquely truncated, and finely concentrically sculpture~; anterior with a faint 

suggestion of a qyssal notch; ctenolium absent. Left valve similar in all respects 

t6 the right except that the anterior ear has a straight, rather than an arcuate end. 

n~:mensions.-Alt. 103 mm.; long. 1l3 mm .. ; hinge line · 40 mm.; diameter 

20 mm. 

This very · unique species, of which there are · no closely allied forms in the 

Tertiary or living faunas of the west coast, so far as known, is somewhat 

analog·ous to P. (.Arnttsiurn) rnortoni Ravenel of the Miocene and Pliocene of 

eastern America. It is distinguishable from the latter species, however, by the 

smaller . number, greater promjnence, and more regular arrangement of the 

internal ribs. P. lornpocensis is included in Amusiurn because it appears to 

show stronger affinities for this than for any other group. 

P. lompocensis was first discovered in the limy beds which outcrop about 4 

miles south of Lompoc, Santa Barbara County, where the types, which are now 

in the collection of the California Academy of Sciences, were collected by Mr. 

Frank M. Anderson. At the type locality this unique form is found associated with 

the following species in beds of probable ·lower Miocene age: Pecten crassicardo, 

Ostrea (aff.) titan, Lima n. sp., Oidaris (?) sp.; Terebratella 2 sp., and Sm.della 

• 
MIOCENE PECTENS. 93 

sp. On the ridge between the Upper and Lower Ojai Valleys, Ventura County, 

Mr. Eldridge has found P. lornpocensis with the following species, in beds which 

he thinks are of lower Miocene (Vaqueros) age: Pecten crassicardo, Tur·ritella (cf.) 

lwffmanni, Phacoides sp. (flat), Ostrea sp., Nassa sp., .Dentaliurn sp., Chione sp., 

Leda sp. Bdlan'ttS sp., Tritoni1tm or .Fusus sp. 

RANGE. 

Miocene (lower ~). Four miles south of Lompoc, Santa Barbara County (F. M. 

Anderson); ridge between uppet; and lower Ojai valleys, Ventura County 

(Eldridge). 

PECTEN (HINNITES) GIGANTEUS Gray. 

Pl. XXIX, figs. 1, 2, and 2. a 

1826. Hinnites giganteus Gray, Ann. Phil., 2d ser., vol. 12, 1826, p. 103. 

1834. Hinnita poulsoni Conrad, Jour. Acad. Nat. Sci., Phila., vol. 7, p. 182, pl. 14. 

1843. Hinnites giganteus Gray, Sowerby, Thes. Conch., vol. 1, Hinnites, p. 80, pl. 20, figs. 3-5. 

1853. Hinnites g1'ganteus Gray, Reeve, Conch. Icon., vol. 8, Hiitnites, Oct., 1853, sp. 2, pl. 1, fig. 3. 

1857. Hinnite8 cras8a Conrad, Pac. R. R. Rept., vol. 7, pt. 2, p. 190, pl. 2, figs. 1 and 2. 

1863. Hinnite8 g·iganteu8 Gray, Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1863. Hinnites cra88a Conrad, Carpenter, Brit. Assn. Rept., 1863, p. 595. 

1869. Hinnite8 giganteus Gray, Gabb, Pal. Cal., vol. 2, 1869, p. 105. 

1887. Hinnite8 giganteu8 Gray, Whiteaves, Trans. Roy. Soc. Canada, vol. 4, sec. 4, 1887, p. 119. 

1888. Pecten (Hinnite8) giganteus Gray, Kuster, and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondy!us und 

Pecten, sp. 228, taf. 65, figs. 9 and 10. 

1888. Hinnites giganteus Gray, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 243 (Santa Rosa 

Island record excepted). 

1892. Hinnite8 giganteus Gray, Keep, West Coast Shells, p. 165, fig. 138. 

1892. Hinnites giganteu8 Gray, Williamson, Proc. U. S. Nat. Mus., vol. 15, 1892, p. 193. , 

1898. Hinnites giganteu8 Gray, Dall, Trans. \¥ agner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 711. 

1898. Hinnites cras8a Conrad, Dall, Trans. ·wagner Free Inst~ Sci., vol. 3, pt. 4, p. 711. 

1903. Pecten (Hinnite8) giganteu8 Gray, Arnold, Mem. Cal. Acad. Sci., vol. 3, pt. 2, 1903, p. 115. 

1904. Pecten (Hinnite8) giganteus Gray, Keep, West American Shells, p. 42, fig. 22. 

Descr'ljJtion.-Shell averaging about 75 millimetm·s in altitude, usually not 

quite so long as high, irregular, inequivalve, generally inequilateral on account of 

attachment to irregular sudace; shell quite thick; margins smooth. Right valve 

more ventricose than left, ornamented by 9 to 18 narrow, irregular, prominently 

squamose ribs, between which in the flat interspaces are less prominent raised lines 

similarly sculptured; hinge line more than one-half length of disk; ears subequal, 

and more or less prominently sculptured by fine, squamose, radiating lines; byssal 

sinus sometimes visible. Left valve less ventricose tha,n right, othenvise similar. 

Hinge rather narrow and heavy; fosset deeply excavated, oblique, narrow, and 

angular; hinge is dark purple in living shells. 

Dimensions.-Alt. 70 mm.; long. 65 mm.; hinge line 40 mm. in length, 10 mm. 

in wi<.lth; diameter 35 mm. 

The young of this species is free swimming until an altitude of about .20 or 30 

millimeters is reached, when they become attached to some fixed object. If this 

object happens to have an irregular surface, as is generally the ease, the shell grows 

irregular in consequence. The young, up to the time of attachment, are indis-
.. 

94 TERTIARY AND QUATERNARY PECTENS o~· CALIFORNIA. 

tinguishable from the young o£ P. lwstat?.ts and varieties, except possibly . that 

the ribs on the right valve o.f I-Iinn1:tes are rather more irregular in size than those 

of Oh[a.mys. · 

After comparing Conrad's types of Hinnites crassa )Vith a large series of living 

Hinnites giganteus, the writer has no hesitation in pronouncing the two species 

identical. . The types of H. crassa were collected from the upper Miocene near 

Santa Margarita. (See PI. XXIX, fig. 1.) · ' · · 

P. (Hinnites) giganteus ranges from the lower Miocene to tlie living fauna. Mr. 

Eldridge found it associated with Turrritella lwffmanni in a small gulch east or 

Wiley Canyon, Ventura County. RANGE. 

Living. Strait of Fuca to San Diego (Cooper); Quatsino Sound, B. C. (Dawson). 

Pleistocene. Santa Barbara to San Diego (Cooper); uppe:r and lower San Pedro 

formation, San Pedro (Arnold). 

Pliocene. Pacific Beach, San Diego (Arnold); Ventura County, Los Angeles County · 

(Cooper). 

Miocene (upper). Santa Margarita, San Luis Obispo County (Conrad). 

Miocene (lower). Gulch east of V\7 iley Canyon, Ventura County (Eldridge}. 

Miocene (horizon?) Carrizo Creek district, San Diego County (Bowers).· 

PLIOCENE PECTENS. 

[Those known first to appear in the Pliocene formations.] 

PECTEN (PECTEN) AUBURn: n. sp. 

Pl. XXXIII, figs. 2. and 2a; Pl. XXXIV, figs. 2 and 2a. 

1900. Pecten indet., Merriam, Bull. Cal. St. Min. , Bureau, No. 19, 1900, p. 222. 

Description.-Adult shell averaging about 60 millimeters in altitude, somewhat . 

longer than high, inequivalve, plano-convex, equilateral, and with smooth margins. 

Right valve convex and ornamented by about 16 or 17 prominent, rather narro~, .. 

convex-topped ribs; 'interspaces slightly n~rrower than the ribs, and with concave · 

bottoms; whole surface sculptured by prominent, fine, sharp, subequal incremental 

lines; hinge line less than one-half length 9f disk; ears subequal and convex; 

anterior ear with two or three obsolete radiating ridges, prominent concentric. 

sculpture, and small byssal notch; posterior ear with concentric sculpture only. 

Left valve flat or slightly concave, ornamented . by 16 or 17 prominent, narrow, 

convex-topped ribs, which are separated by deep, almost flat-bottomed interspaces 

slightly wider than the ribs; whol~ surface sculptured by prominent, fine, sharp, 

·equal, concentric lines; ears slightly .concave, rectangularly trunc.ated, and sculptured 

by fine, sharp, concentric lines. 

Dimensions.-Alt. 47 mm.; long. 50 mm.; hinge line 21 mm.; diameter ·12 

mm.; umbonal angle (left valve) 93°. · 

This species is quite closely related to P. lecontei, but is distinguishable from 

the latter by the smaper angle at the apex (102° in the latter),' much narrower 

sharper ribs, and stronger sculpture on the right valve. 

P. auburyi has so far been found only in beds of probable lower Pliocene age. 

About 1 mile east of the Chandler well~. Puente Hills, Los Angeles County, it is 
PLIOCENE PECTENS. 95 

associated, according to Doctor 1\ferriam (see :Merriam, 1900, p. 222), with Cancellaria 

2 n. sp., Crepidul(~ sp. indet., Drillia sp., Hinnites near giqanteus, 1Yatica (1Yeverita 

(aff.) recluziana, }Jriene (aff.) oregonen.;is, Ran ella californica, and Trochita sp. indet. 

At Olinda, Puente Hills, Orange County, Mr. Eldridge found P. auburyi with 

the following lower Pliocene fauna: Pecten ashleyi, P. wattsi, P~ oweni, var., Priene 

(a if.) oregonensis, OardiuTn ( cf.) quadrigenari1-t1n, Neverita recluziana, Phacoides 

califm·nicus, Atsus (qf) barbarensis, Area multicostata ( ~), Nassa perpinguis ( ~), 

Chione sp., L eda taphria, Fissuridect murina, Nassa fossata, Phacoides ·richthofeni, 

Phacoides nuttalli, Pl~;acoides (cf.) acutilineatus, Oard1:U1n (cf.) corbis, CAione sp., 

.Dentalittrn neohewagonurn, Solen ( rf.) sicaritts, Turritella cooperi, Crepidula r'ugosa, 

Astyris sp., Cancellaria n. sp., Calliostorna costatttm, Modiolus ( qf.) rect?,ts, Bulla 

p11mctulata, and Dentaliurn n. sp. (like Miocene form). 

The type specimen is from the first-mentioned locality, and is now in the State 

Mining Bureau. Named in honor of Mr. Lewis E. Aubury, State Mineralogist of 

California, through whom the writer was enabled to procure the valuable Pecten 

material in the State museum. 

RA~GE. 

Pliocene. · Locality 38, 1 mile east of the Chandler wells, Puente Hills, Los Angeles 

County (Watts): Several localities in the vicinity of Olinda and Brea Canyon, 

Puente Hills, Orange County (Eldridge). 

PECTEN (PECTEN) BELLUs Conrad. 

Pl. XXXI, figs. 1 and 1a. 

1857. Janira bella Conrad, Proc. Acad. Nat. Sci. Phila., for 1856, p. 312. 

1857. Janira bella Conrad, Pac. R. R. Rept., vol. 6, 1857, p. 71, pl. 3, fig. 16. 

1869. Janira bella Conrad, Gabb, Pal. Cal., vol. 2, 1869, p. 105, pl. 16, fig. 20. 

1888. Janira bella Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 244. 

1898. Pecten (Pecten) bellus Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 704; not 

P. bellis McCoy (teste Dall, 1898). 

1900. Vola sp. indet., Merriam, Bull. Cal. St. Min. Bureau, No. 19, 1900, p. 222, table III. 

1903. Pecten (Pecten) bellus Conrad, Arnold, Mem. Cal. A,cad. Sci., vol. 3, 1903, p. 103, pl. 21, figs. 1, 2 . 

.Descr1pt1:on.-Shell large, thin, inequivalve, elegantly, radiately ribbed. Left 

(upper) valve slightly convex, the point of greatest convexity being generally about 

one-fourth the distance from the apex toward the ventral margin; between this point 

of greatest convexity and the apex there is a deeply depressed area, the depression 

generally not affecting the two outer ribs on each side, which inclose the depression 

on the sides; surface of left valve ornamented by 13 or 14 prominent, fiat-topped, 

sometimes faintly bicarinated, radiating ribs, which have fiat, sloping sides; these 

ribs become broader, less elevated, and less sharply angulated near the periphery in 

the adult; interspaces slightly wider than the tops of the ribs, with slightly rounded 

bottoms; whole surface of left disk covered with fine, sharp, concentric, regular 

lamellre; ears rather small, subequal, slightly concave, finely concentrically lamellated, separated from the disk by an impressed line. Right (lower) valve prominently convex, the point of greatet:lt convexity being about one-th!rd the distance 

from the apex to the ventral margin of the disk; the umbo in this valve curves 

sharply and meets the plane of the ears at an angle of about 90 degrees; surfaee 
/ 

96 t 

TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

of right valve ornamented by 14 or 1f> prominent, nearly flat-topped, square, radiating ribs, some of them with one or two longitudinal obsolete lines; the ribs become 

somewhat less elevated and the sides more sloping as the periphery is approached in 

the adult; surface of right disk ornamented with close, fine, squamose, concentric 

wrinkles; ears subeq~al, arched, covered with crowded, elevated lamellre; byssal 

notch small. 

Dimensions.-Alt. 80 mm.; Jat. 108 mm.; diam. 32 mm.; length of binge 

line, 45 mm. 

The description, measurements, and figures are of Gabb's type specimen of 

Janira bella (No. 960, Collection Academy Natural Sciences, Philadelphia), which 

was kindly lent to the writer by Prof. H. A. Pilsbry, curator of Mollusca. 

P. stearnsii and P. diegensis are distinguishable from· P. bellus by the more 

numerous (25 or 28 in the first, 20 or 22 in the second), narrower, sharper defined, 

perpendicular-sided, radiating ribs on the right valve, and by the evenly rounded., 

prominently and evenly lamellated ribs of the left valve. P. hemphilli is distinguishable from P. bellus by its smaller size; by having on the right valve more 

numerous (15 or 16 in the former), round-topped, narrower, nearly perpendicularsided, radiating ribs, which retain their prominence for -their entire length; by 

the less convexity of the disk; and by the more numerous, narrower, and more 

elevated radiating ribs of the left valve. P. hemphilli has the same depression 

below the apex in the left valve, but the lesser convexity of the rest of the 

. disk lessens the prominence of the depression, which is so marked in most specimens of P. bellus. P. excavatus is distinguishable from P. bellus by its smaller 

size, greater convexity of right valve, greater concavity of left valve, greater 

number of ribs, and- by the auxiliary ribs in the left valve. 

After a careful comparison of a large series of P. bellus with Conrad's description and figure and Gabb's figure and type specimen, the writer has no hesitancy 

in adopting the synonymy given at the beginning of this article. Dall is of the 

opinion that Conrad's species and that 'Of Gabb are different. This idea was 

probably caused by the exaggeration of the bicarination of the ribs in Conrad's 

figure. Several of the specimens of I>. bellus examined by the writer show this 

bicarination to a greater or less degree, although as a rule the ribs are nearly 

smooth-topped. A Jarge series of P. bellu8 and P. hemphilli show the differences 

enumerated in a previous paragraph to be constant for ·the adults. The young 

of both ·species up to an altitude of 20 millimeters are nearly identical in 

appearance. . 

P. bellus, so far as known, is confined to the Pliocene. It occurs abundantly in 

the Pliocene formation on Packards Hill, Santa Barbara, and in other localities 

m the vicinity. The type was obtained near Santa Barbara. 

RANGE. 

Pliocene. Santa Barbara (Conrad; Gabb; Yates; Cooper; Arnold); Top of hill, 

Long Tom mine, Kern County (Watts); Eureka Canyon, west side, near 

mouth, Ventura County (Eldridge); Rincon a~pbalt mine, Santa Barbara County 

(Watts); Loc. 33, east side of Piru Creek, near railroad bridge, Ventura County 

(Watts); ?. Temescal Canyon, north of Santa Monica, Los Angeles County 

(Rivers). 
PLIOCENE PECTENS. 97 

PECTEN (PEC'FEN) COALINGAENSIS n. sp. 

Pl. IV, figs. 4, 4a, and 5 . 

.Description.-Shell about 45 millimeters in altitude, longer than high, planoconvex, or nearly so, equilateral, and with smooth margins. Right valve 

ventricose and ornamented by about 20 ribs which have narrow, somewhat convex 

tops, and sides which slope at angles of about 45° ; interspaces quite deeply 

impres:::;ed, channeled, and flat bottomed; surface sculptured by fine incremental 

lines; hinge line slightly longer than one-half length of disk; ears equal, convex, 

and ornamented by 2 or 3 obsolete radiating ridges and numerous fine incremental 

lines. Left valve flat, with 19 prominent convex ribs, a surface sculpture of fine 

regular incremental lines, and concave ears which are slightly obliquely truncated. 

Dimensions.-Alt. 45 mm.; long. 5~ mm.; hinge line 28 mm.; diameter J 8 mm. 

This species is easily distinguishable by the peculiar shape of the ribs on the 

right valve. The type (right valve) was collected by Mr. L. D. O'Neal from 

beds of probable lower Pliocene age near Coalinga, Fresno County, and is now 

in the collection of the Leland Stanford Jqnior University. A left valve, which 

is undoubtedly of this species, was found by Mr. Watts near Kreyenhagen's ranch, 

Fresno County, and is now in the collection of the California Academy of Sciences. 

This left valve measures as follows: Alt. 35 mm.; long. 37 mm.; hinge line 13 mm. 

RANGE. 

Pliocene (lower). Coalinga, Fresno County (L. D. O'Neal); Kreyenhagen's ranch, 

Fresno County (Watts, Anderson, Arnold). 

PECTEN (PECTEN) HEMPHILL! Dall. 

Pl. XXXIII, figs. 3, 3a, and 3b. 

1879. Pecten hemphilli Dall, Proc. U. S. Nat. Mus., vol. 1, 1879, p. 15. 

1888. Pecten hemphilli Dall, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 257. 

1898. Pecten (Pecten) hemphilli Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 706. 

1903. Per;ten (Pecten) hemphilli Dall, Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 105. 

Description.-Shell of medium size, thin, inequivalve. Upper (left) valve flat 

or slightly concave, with a concave depression betwe~n middle of valve and umbo; 

surface of this valve sculptured by 16 or 17 very prominent, rather narrow 

radiating ribs, which are nearly flat-topped and have nearly perpendicular sides; 

interbpaces wider than ribs, with rounding bottoms; fine incrementallamellre cover 

the surface of this valve; ears square-cornered and concave, covered with incremental 

lamellre. Lower (right) valve convex, the convexity being most apparent between 

middle of valve and umbo; sculptured by 16 prominent squarish ribs, which are 

similar to those on the upper valve, except that they are slightly broader and have a 

more rounded top; whole surface sculptured by very fine incremental lines; ears 

similar to those of upper valve except convex, the right one having 3 or 4 radiating 

ridges and a small byssal notch. 

17260--No. 47--06----7 
98 TERTIARY AND QUA';I'ERNARY PECTENS OF CALIFORNIA. 

Dimensions.-Alt. 56 mm.; long. 63 mm.; diam. 15 mm.; hinge line 28 mm. 

This species is readily distingui8hable from P,. stea'l·nsii and P. diegensis by 

its smaller size, greater convexity of lower valve, and fewer ribs. Distinguishable 

from P. bellius by smaller size, flat, or concave upper valve, and narrow, more 

elevated and prominent, radiating ribs. Common in the upper horizon of the 

Pliocene at Pacific Beach, and also in the strata exposed on Tenth street, near 

Russ School, San Diego. 

RANGE. 

Pliocene. Temescal Canyon, north of Santa Monica, Los Angeles County 

(Rivers); Pacific Beach, Russ School, and "San Diego well," San Diego 

(Hemphill, Dall, Arnold). 

PE9TEN (PECTEN) LECONTE! n. sp. 

Pl. XXXIII, figs. 4, 4a, and 4b. 

Descri_ption.-Shell averaging about 60 millimeters in altitude, longer than 

high, plano-convex, equilateral, and with smooth margins; base evenly rounded; 

sides concave above. Right valve convex, and ornan;tented by about 18 prominent 

round-topped, perpendicular-sided, smoothish ribs, separated by interspaces, which 

are narrower than the ribs and have nearly flat bottoms; surface sculptured by 

fine wavy incremental linel::l, which are generally worn off from the tops of the 

ribs; hinge less than one-half the length of the disk; ears somewhat convex; 

the anterior with 2 or 3 broad,. nearly obsolete, radiating ridges, imbricating 

incremental lines, and a rather small byssal notch; the posterior rectangularly 

truneated, and with fine incremental sculpture. Left valve flat or slightly concave, 

ornamented by about 17 prominent rounded ribs, which are separated by interspaces about equal in width to the ribs; surface sculptured by numerous fine, 

sharp, regular, raised, incremental lines; ears concave, rectangularly truncated, 

and covered by fine sharp incremental lines. 

Dimensions.- -Alt. 59 mm.; long. 65 mm.; hinge line 29 mm.; diameter 18 

mm.; umbonal angle (left valve) 102° . 

This species is distinguishable f:rom P. diegensis, P. bellus, P. stean.f;sii and 

other members of this group by the number and convexity of the ribs on the 

right valve. The left valves of P. lecontei and P. diegens1~s are somewhat similar, 

although the former has fewer ribs and is generally slightly more concave. 

P. lecontei has so far been found only in the Pliocene of Cerros Island, where 

it is ass~ciated with P. veatchi1:, P. cerrosens£s, and Ostrea veatchii. The type is 

now in the collection of Delos Arnold. Named in honor of the late ,Prof. Joseph 

Le Conte, of the University of California. 

RANGE. 

Pliocene. Cerros Island, Lower California (University of California). 
PLIOCENE PECTENS. 99 

PECTEX (PECTEN) ~IERRIAMI n. sp. 

Pl. XXX, figs, 1, la, and 2. 

1900. Pecten meekii Merriam (not of Conrad, 1857=P. ccmrinns Gould), Bull. Cal. St. Min. Bureau, 

.No. 19, 1900, p. 222. 

Description.-Shell averaging about 115 millimeters in altitude, longer than 

high, inequivalve, equilateral, of medium thickness, and with smooth margins; 

base evenly rounded; sides straight or only slightly concave above, sloping at a 

rather low angle. Right valve decidedly ventricose, with 18 or 19 subequal, 

strong, square ribs, some of which show faint medial sulcations near their 

extremities; interspaces flat-bottomed and somewhat narrower than ribs; whole 

surface of disk sculptured by more or less prominent lines of growth; hinge line 

1nore than one-half length of shell; ea,rs about equal in length; anterior ear with 

faint byssal notch, obsolete r'adiating ridges and fine incremental sculpture; posterior ear rectangularly truncated, and with faint radial and fine concentric 

sculpture. Left valve flat to concave, with a more or less prominent bulge just 

below the umbo, as in P. bellus; ribs prominent and rounaed, relatively flatter 

and broader as the periphery of the disk is approached; interspaces about as wide 

as the ribs, round-bottomed, and some of them showing a faint intercalary 

riblet; surface sculptured by fine, sharp, looped, concentric lines; ears ornamented 

by 5 or 6 rather prominent radiating ridges and numerous fine concentric lines. 

Dimens·ions.-Alt. 115 mm.; long. 130 mm.; hinge line 70 mm.; diameter 

30 mm. 

P. merr-iami is distinguishable from P. bellus," to which it is allied, by its 

much larger size when adult, more numerous ribs (18 to 19 in the former, 14 to 15 in 

the latter), relatively longer hinge line (the hinge line of the former being about 

60 per cent of the length of the disk, while that of the latter is only about 45 

per cent), and the radial ridg·ing of the ears. 

The types of ·this species, which are the only specimens of it so far known, 

were collected by Mr. Watts from light-colored shale underlying the conglomerate 

on San Felician Creek, near Piru, Ventura County. The following fauna, as 

given by Doctor Merriam, (t was associated with P. 1nerriami at the type locality: 

Echinarachnins near emcentricus, Macoma near secta, Nassa sp. indet., Pachypoma 

n. sp. ~ Solen sicarius, and, as determined by the writer, Pecten cerrosenst:s. This 

fauna indicates beds of probable lower Pliocene age. The type of P. merriami 

is now in the collection of the California State Mining Bureau, San Francisco. 

Named in honor of Dr. John C. Merriam, professor of paleontology, University of California, to whom paleontologists are indebted for so much of their 

knowlerlge regarding the faunas of the California Tertiary. 

RANGE. 

Pliocene (lower). San Felician Creek, near Piru, Ventura County (Watts). 

aBull. Cal. St. :Min. Bureau, ~o. 19, 1900, pp. 220-222. 
100 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

PECTEN (PEcTEN) STEARNSII Dall. 

Pl. XXXII, figs. 1 and 1a. 

1869. Janira dentata Gabb (not Sowerby), Pal. Cal., vol. 2, 1869, P• 104 (in part). 

1879. Pecten stearnsii Dall, Proc. U. S. Nat. Mus., vol. 1, 1879, p. 14. 

1888. Janira dentata Cooper (not Sowerby), Seventh Ann: Rept. Cal. St. Min., 1888, p. 244 (in part). 

1898. Pecten (Pecten) stearnsii Dall, Trans. Wagner Free Inst. Sci, vol. 3, pt. 4, 1898, p. 706, pl. 26, fig. 5. 

1900. Vola sp. indet., Merriam, Bull. Cal. St. Min. Bureau, No. 19, 1900, p. 222, table 4. 

1903. Pecten (Pecten) steamsii Dall, Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 106, pl. 12, fig. 3. 

Description.-Shell of medium size, subeircular, inequivalve, concavo-convex, 

thin; right valve slightly convex, with about 26 regular, even, square ribs, separated 

by channeled interspaces somewhat na1~rower than the ribs; the top surface of each 

rib is flattened with a broad, shallow groove in the middle, with one or two faint 

riblets on each side of the groove; whole surface covered with concentric lamelloo 

which are much finer and about twice as crowded as those of the left valve; left 

valve flattened or concave, with about 24 regularly rounded, vaulted, even ribs, 

separated by slightly wider channeled interspaces; the whole surface covered with 

fine, sharp, concentric, regular lamelloo, a little looped backward over the tops of 

the ridge; ears of this valve concave, with obsolete radiating ridges, and fine, concentric lamelloo; ears of right valve subequal, arched, covered with crowded, 

elevated lamelloo; byssal notch very small. 

Dirnensions.~Alt. 62 mill.; long. 71 mm.; diameter 14 mm.; hinge 25 mm. 

According· to Doctor Dall this is the precursor of ]:>. diegensis, from which it 

differs by having 5 or 6 more ribs, which in the adult have a conspicuous medial 

sulcus. · 

J>. stearnsii, so far as known, is confined to the Pliocene. It is quite abundant 

at Pacific Beach, ne~r San ·Diego, where it is associat.ed with P. healeyi, P. hemphilli, Opalia varicostata~ 0. anomala, Scala stearnsii, Pecten panneleei, and other 

unique forms. In a well at San J nan Capistrano it was found by Watts associated 

with Turritella cooperi, Venericardia ventricosa, Area trilineata, Nassa rrnendica, etc. 

Two left valves have been found in the Pliocene at Deadman Island, near San Pedro. 

RANGE. 

Pliocene. Temescal Canyon, Santa lVIonica Mountains, Los Angeles County (Watts, 

Rivers); San Pedro (Aruold); San Juan Capistrano, Orange County (Watts); 

Pacific Beach, near San Diego (Hemphill, Stearns, Dall, Arnold); Third street 

tunnel, Los Angeles (Hamlin). 

PECTEN (PECTEN) VOGDESI n. sp. 

Pl. XXXIII, figs. 1 and 1a; Pl. XXXIV, fig. 1. 

1888. Janim dentata Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 244 (Quaternary records). 

1903. Pecten (Pecten) dentattts Arnold, Mem. Cal. Acad. Sci., vo!. 3, 1903, p. 105 (Pleistocene record). 

Description.-Shell similar toP. exca/vatus, except averaging larger and with the 

following differences: Right valve, somewhat less convex, bas 19 or 20 broader, flatter 

ribs, which are separated by relatively broader interspaces that occasionally show 

faint intercalary riblets or faint longitudinal striations. Left valve with fewer ribs 
PLIOCENE PECTENS. 101 

than P. excavattts, and having no intercalary riblets, or else faint ones, which become 

ubsolete near the periphery of the disk; ears slightly less concave than in P. excavatus. 

DiJnensions.-Alt. 69 mm.; hinge line to ventral margin (right valve) 67 mm.; 

long. 73 mm.; hinge line 35 mm.; diameter 24 mm.; umbonal angle (left valve) 98°. 

All of the Pleistocene specimens of the group of which I~. exca-vattts is the living 

representative have the constant differential characteristics above enumerated. These 

differences are so constant and so pronounced that they are deemed by the writer to 

be of specific importance. 

A fragment of a right valve in the California Academy of Sciences from the 

Pleistocene of Ventura County is 9ver 120 millimeters in length. 

The type of this species (a right valve) is from the upper San Pedro formation 

at San Pedro;and is now in the colleetion of Delos Arnold. The cotype, a left valve -

from the Pleistocene of Ventura County, is now in the collection of the California 

Academy of Sciences. The horizon of some large specimens of thi~ species in the 

Philadelphia Academy collected by Mr. Hemphill near San Diego is uncertain. 

Named in honor of Gen. A. W. Vogdes, U.S. Army. 

Pleistocene. 

Pliocene ( n. 

RA:NGE. 

San Pedro (Arnold); Ventura County (Bowers); San Diego (Hemphill). 

San Diego (Hemphill); Cholas Valley, near San Diego (Stearns). 

PECTEN (PAnNOPECTEN) CAURINUS Gould. 

Pl. XXXVIII, figs. 1, la., and lb; Pl. XXXIX, figs. 1 and 2. 

1850. Pecten ca.urinus Gould, Pro c. Bost. Soc. Nat. HisL, vol. 3, 1850, p. 345. 

1852. Pecten ca.urinus Gould, Wilkes Expl Exped., vol. 12, p. 458, figs. 569, 569a, 569b. 

1855. Pecten Heermanni Conrad, Proc. Acad. Nat. Sci. Phila., vol. 7, 1855, p. 267 (not P. (Lyropecten) 

Heermanni Dall, Trans. \Vagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 701, nor Pecten Heermanni 

Dall, Nautilus, vol. 14, 1901, p. 117, =P. estrellan'us Conrad). 

1857. Pecten -<Weekii Conrad,Proc. Acad. Nat. Sci. Phila., for 1856, 1st ser., vol. 8, 1857, p. 313. 

1857. Pecten J.lfeekii Conrad, Pac. R. R. Rept., vol. 7, pt. 2, 1857, p. 190, pl. 1, fig. 1. 

1863. Amusium caurinum Gould, Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1863. Pecten Yessoensis Carpenter, loc. cit., p. 645 (not P. Ye..;soensis Jay, Perry's Voyage, 1856); + P. 

propatulus Carpenter, luc. cit., p. 679 (not Conrad, 1849). Fide Dall, 1898. 

1886. Not Pecten caurinns Dall, Bull. Mus. Comp. Zool., vol. 12, p. 216, pl. 5, fig. 4, 1886 ( = P. 

vancouverensis vV hi tea ves). 

1888. Pecten caurimts Gould, Kuster and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondylus und Pecten, 

sp. 108, p. 152, taf. 43, fig. 1. 

1888. Amttsium caurim1,s Gould, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 228 (excepting 

"Japan"). 

1888. Pectenpropatulus Cooper, loc. cit., p. 258 ("Eel River, Humboldt County"). 

1889. Not Pecten ccmrinus Dall, Bull. U. S. Nat. Mus., no. 37, 1889, pl. 5, fig. 4 ( =P. vancouverensis 

Wbiteaves). 

1892. Pecten caurinus Gould, Williamson, Proc. U. S. Nat. Mus., vol. 15, 1892, p. 193. 

1892. Amusium ca.urinum Gould, Keep, 'Y est Coast Shells, 1892, p. 168. 

1898. Pecten ( Patinopecten) caurinus Gould, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, 

p. 710. 

1903. Pecten (Pcttinopecten) caurinus Gould, Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 107, pl. 13,. 

fig. 6. 

1903. Not Pecten caurinus Dall, Bull. U. S. Nat. Mus., no. 37 (reprint), pl. 5, fig. 4, 1903 ( =P. 

vancouverensis Whi tea ves). 

1904. Pecten c~urinus Gould, Keep, W estJ Am. Shells, pp. 38-39. 
102 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

Description.-Shell averaging about 150 millimeters in altitude, slightly 

longer than high, valves much compressed (the right generally slightly more 

convex than the left), equilateral, and with smooth margins; sides straight 

or only slightly eon~ave above. Right valve w1th 20 to 25 strong, flat-topped, 

squa.rish ribs, which, i.n some well-preserved specimens, show faint obsolete radial 

stri&; interspaces flat-bottomed and about equal in width to the ribs; whqle 

surface of disk sculptured by fine incremental lines; hinge line less than onehalf length of disk; anterior ear only very slightly longer than posterior, 

ornamented with fine, sharp, incremental lines, but generally having no · radial 

sculpture whatever; byssal notch prominent; postm~ior ear rectang-ular behind, 

and with sculpture similar to anterior. Left valve slightly less ventricose than 

right, with narrow rounded ribs and wide concave-bottomed interspaces; surface 

ornamented by fine, regular, raised, wavy, concentric lines, and sometimes more 

or less tesselated; ears obliquely truncated and sculptured with sharp incremental 

lines and sometimes by obsolete radiating ridges. 

D1:mensions.-Alt. 105 mm.; long. 110 mm.; hinge line 48 mm.; diameter 

15 mm. 

The measurements are for a specimen considerably under the' average in size. 

This species has caused considerable confusion in the nomenclature of the 

West Coast. In 1855 Conrad described a couple of small right valves of P. cm.trinus 

and named the speeies ''Pecten Heerm.ann?.:." The following is his original description and notes (see synonymy above): "Suborbicular, thin, compressed; ribs about 

21, square, smooth; ears moderate in size. Locality, California. Doctor Heermann. 

Allied to P. eboreus of the Virginia Miocene, but very distinct; only two inferior 

valves were obtained; slightly convex." The type of P. Heermanni (so labeled 

in Conrad's own writing), and the other specimen referred· to in· the description 

are now in the Philadelphia Academy of Sciences, where they were examined and 

photographed by the writer. They are both right valves of young P. Ca1Jll'inus 

and' undoubtedly came from the unique bryozoan marl of Santa Barbara, both 

specimens showing the characteristic matrix and blue-gray color of specimens 

of P. caurinus from that locality. ·Some time after 1855 Conrad labeled a 

P. estrellanus and also some fragments of P. miguelensis in the National Museum 

with the name '~P. Heermanni." One of these latter specimens is referred to 

by Doctor Dall (see Dall, 1898 and 1901) as the type of P. Heermanni. This 

error of Conrad's caused Dall to apply the name '' Heermanni" to P. e8trellanus. 

The type of P. Meekii Conrad is in the National Museum (No. 13333) and 

has been examined by the writer. It, also, is a P. caurin1.t8 from the bryozoan 

marl of Santa Barbara. The "•San Raphael Hills," from whence the type of 

P. Meekii came, according to Conrad, are near Santa Barbara. 

P. Y essoensis Jay, from Amori, Rikonoken, Japan, differs from P. caur1;nus 

by having a more convex shell, wider, lower, more rounded ribs on the right 

valve, less prominent ribs on the left valve, and by having larger ears, which 

are truncated more nearly at right angles. 

P. caurinus ranges from thP. Pliocene upward. It has been reported from 

the Miocene by several authors, but so far none of these records have been 

authenticated. 
PLIOCENE PECTENS. 103 

A Pecten having 19 ribs, and allied to, if not identical with, P. cattrinttS, was 

found in the lower Pliocene Cn /sandstone at the mouth of tne Raft River, 

Jefferson County, "\V ash. The ribs on the right valve of this specimen were 

narrower and those on the left valve were somewhat higher than those of a 

typical caur~:nus. 

Pecten ca·urin·ns is found abuntlantly in the lowe1' Pliocene along Eel River, 

Humboldt County. Some of the specimens from this locality have as many as 

25 ribs, and the ribs are, in some cases, higher and narrower than in the typical 

form. On Eel River above the mouth of Price Creek, Mr. J. S. Diller found · 

P. cattrinus associated with the following fauna: Astyris t:chtlwfeni, Oallista 

subdictph.ana, Ohrysodomus n. sp., K ennerlict g1·andis, K bicarinata, JY!acmna 

calcarea, .1lfacont-a (cf.) nasuta, Natica clausa, ]Janomya ampla, Pleurotmna perversa, 

Priene n. sp. (?) near oregonensis, Tapes staleyi, Thracia. trapezoides, Trophon 

near 1nulticostatus, and Yoldia scissurata.' This is a Pliocene fauna. 

From Switch Gulch to French Gulch, on the Eel River, P. ca?.trinus is found 

with the following: Cardium meekian.um, Natica clansa, Mactra (cj:) californica, 

Siliqua patula, Macoma calcarea, M. inquinata, Tapes staleyi, Tresus mdtalli, 

Solen (cf.) sicarius, Pleurotoma perversa, Tkracia trapezoides, Ohrysodomus n. sp., 

Yoldia scissurata, Psephis (cf.) tantilla, Troplwn near m·ulticostatus, Scutella or 

Echinarachnius sp. indet. This is also a Pliocen8 fauna. 

A magnificent specimen of P. caurin1lB, measuring nearly 200 millimeters in 

altitude, was found by Dr. Stephen Bowers in the Pliocene near Santa Paula, 

Ventura County. 

The type of P. caurintts is in the U. S. National Museum, No. 5954. 

I RANGE. 

Living. Puget Sound (Carpenter). 

Pleh;tocene. Santa Barbara; San Pedro (Cooper, Mrs. A. E. Bush, Arnold). 

Pliocene. Mouth of Raft River, Jefferson County, Washington (Arnold); above 

mouth of Price Creek, from Switch Gulch to French Gulch, and south of the 

middle of Rio De1l Bluff, Eel River (J. S. Diller); Eel River, Humboldt 

County (W. S. 1\-Ionroe, A. C. Lawson); T. 1 N., Humboldt meridian, Humboldt 

County (J. M. Graham); Eagle Prairie, Humboldt County; San Fernando, Los 

Angeles County (Cooper)~ S~nta Paula, Ventura County (Bowers, Watts); 

Santa Barbara; San Pedro (Arnold). 

PECTEN (PATINOPECTEN) :UEALEYI n. sp. 

Pl. XXXVI, figs. 1 and 1a; Pl. XXXVII, figs. 1, 1a, and 2. 

1879. Pecten expansus Dall, Proc. U. S. Nat. Mus., vol. 1, 1879, p. 14; not Pecten expansu.~ Smith, 

Quart. Jour. Geol. Soc., vol. 3, 1847, pp. 413, 419, pl. 18, fig. 21. 

1898. Pecten ( Patinopecten) expansus Dall, [I'rans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 706, 

pl. 26, fig. 1. 

1903. Pecten ( Patinopecten) expansus Dall, Arnold, Mem. Cal. Acad. Sci:, vol. 3, 1903, p. ·108. 

1904. Pecten expansus Dall, Rivers, Bull. So. Cal. Acad. Sci., vol. 3, no. 5, p. 69. 

Description.-ShelJ averaging about 130 millimeters in altitude, length about 

equal to height, inequivalve (the right slightly more ventricose than the left), 

equilateral, and with smooth margins; base evenly rounded; sides only slightly 
104 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA.. 

concave above. Right valve somewhat ventricose, and ornamented by 18 to 21 

strong, squarish, subequal primary ribs, which become more or less dichotomous, 

and -sometimes trichotomous, after 30 . or 40 millimeters in length; medial sulcus 

of rib more ·. or less deep, in some cases being as deep as the inters paces near 

the ends, thus completely dividing the primary rib; interspaces subequal, much 

narrower than the ribs, quite deeply channeled, and often ornamented by a small, 

rounded intercalary riblet; .... whole surface crossed by numerous fine lines of growth; 

hinge line less than one-half length of disk; anterior ear only slightly longer 

than left, arcuate in front, and ornamented by several obsolete radial ridges and 

numerous sharp incremental lines; byssal notch quite prominent; posterior ear 

slightly obliquely truncated, and ornamented by sharp incremental lines and 

sometimes by obsolete radiating ridg-es. Left valve much compressed; ribs narrow 

and rounded, more or less sharply toward the top (there being in some cases a 

narrow, slightly raitjed line along the top); interspaces wide, and each ornamented 

by a more or less prominent, rounded, intercalary riblet; whole surface striated 

concentrically by fine, sharp, wavy lines; ears obliquely truncated and sculptured 

similarly to those of the right valve. 

Di?nen.<?ions.-Alt. 112 mm.; long. 112 mm.; hinge line 50 mm.; diameter 18 mm. 

The measurements are of a specimen somewhat below the average in size. A 

fine specimen from San Gregorio, San Mateo County, measures 180 mm. in altitude. 

The most variable factors in this ,species seem to be the depth and width of the 

medial sulci on the rihs of the right valve, and the prominence of the intercalary 

riblet in the left. 

The specimens from San Gregorio and Pescadero, San Mateo County, show, on 

the average, flatter rihs, more highly developed medial sulci, and intercalary ribs on 

the left valve that almost equal the primary ones in importance. Specimens from 

Purisima and Lobitas, which appear to represent a .somewhat lower horizon than the 

San Gregorio and Pescadero beds, are smaller, slightly more convex, and have two or · 

three less ribs. 

As the forms from both San Diego and San Mateo counties appear to vary 

through an almost analogous series of mutations, the slight differences enumerated 

above have not been deemed of even varietal importance. 

A variety of P. lwaleyi with 17 ribs is found at Brea Canyon, 4 miles southeast 

of Newhall, Los Angeles County, associated with the follOwing fauna: Phacoides 

acutilineatus, P. richtlwfeni, Dosinia ponderosa(~), Tritonium sp., Oon1ts n. sp. (n, 

Pomaulax sp., Turritella cooperi, Tellina idm, Neverita recluziana, Trochita · filosa, 

Chione near succincta, Cardium near corbis, 'Nassa near .fossata. This fauna is 

probably well down in the Pliocene. 

P. Aealeyi appears to have a very limited vertical range at the few localities 

where it is known. In San Mateo County it is found in the Purisima formation, 

which lies conformably beneath the Mereed series, while in San Diego it is very 

abundant in beds of lo~er Pliocene age. The great abundance of this species in both 

the Purisima and San Diego formations may possibly be taken as evidence of their 

partial contemporaneity. 

It was with regret that a name so well established in the paleontological literature of the Pacific coast asP. expans·us was found to be preoccupied. Since, however, 
PLIOCENE PECTENS. 1U5 

it becomes necessary to rename the species, it is with pleasure that the writer is 

enabled to dedicate it to Dr. William Healey Dall. 

RANGE. 

Pliocene. Purisima to Pescadero, and Punta Aiio Nuevo, San Mateo County (J. P. 

Smith, Arnold); Temescal Canyon, Santa Monica Mountains, Los Angeles 

County (Rivers); Pacific Beach, San Diego County, (Hemphill, Dall, Arnold, 

and others); Tia Juana, Nlexico (A. W. Greeley); Brea Canyon, 4 miles southeast oi Newhall, Los Angeles County (U. S. Nat. Mus.) 

PECTEN (P ATINOPECTEN) PURISIMAENSIS n. sp. 

Pl. XXXIV, fig. 3; Pl. XXXV, figs. 1 and la. 

Description.-Shell averagil!lg about 125 millimeters in altitude, length same 

as height, valves both equally well compressed, equilateral, and with the margins 

smooth; base regularly rounded; sides relatively short, straight, sloping at a moderate angle. Right valve with about 24 prominent, T-rail-shaped ribs, flattened 

and sometimes faintly dichotomous above, overhanging deep, channeled, flatbottomed interspaces, which are about equal in width to the ribs; whole surface 

of disk with incremental sculpture, which develops into prominent scales on the 

sides of the ribs; hinge line equal to about two-fifths length of disk; anterior 

ear only slightly longer than posterior, sculptured by about three prominent 

radiating ridges and numerous imbricating incremental lines; byssal notch prominent, but not deep, being equ;:tl in width to one-half width of ear; posterior ear 

obliquely truncated, and ornamented hy about three prominent radiating ribs and 

imbricating incremental lines. Left valve with narrow, rather sharp, concavesided· ribs and wide concave-bottorru~d interspaces; surface with fine incremental 

sculpture; ears obliquely truncated and sculptured similar to those of right, except 

that the radiating ridges are finer and more numerous. 

Dimensions.-Alt. 125 mm.; long. 125 mm.; hinge line 50 mm.; diameter 

25 mm. 

This magnificent species is a1lied to P. coosensis and P. dilleri, one of which 

is probably its precursor. P. p1trisimaensis is easily distinguishable, however, by 

the fewer and broader ribs on the right valve, narrower, sharper ribs and broader 

interspaces on the left, and from P. coosensis by the prominent radial sculpture 

of the ears. 

P. purisimaensis is ch:uactetistie of the Purisima (lower Pliocene) formation, 

where it is associated with P. healeyi, P. nutteri, Orepidttla princeps, Phacoides 

ac1dilineatus, Rostellaria ind1-trata, etc. 

The type is from the beds on the coast north of Pescadero, and is now in 

the collection of Delos Arnold. 

RANGE. 

Pliocene (lower). Purisima to Pescadero, and Punta Afio Nuevo, San Mateo 

County (J. P. Smith; W. R. Hamilton; Arnold). 
106 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

PECTEN (PATINOPECTEN) TURNER! n. sp. 

Pl. XXXIV, fig. 4; Pl. XXXV, figs. 2 and 3. 

1888.? Pecten propatulus Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 258 (."Tomales, Marin 

County"). 

Description.-Shell averaging about 70 to 80 millimeters in altitude, length 

same as height, both valves equally compressed, equilateral, and with smooth 

margins; base regularly rounded; sides nearly straight and sloping at a rather low 

angle. Right valve with eighteen to twenty-two high, narrow, flat-topped, concavesided ribs, which, in most cases, show a distinct medial sulcus • after reaching a 

length of 30 or 35 millimeters; interspaces much wider than ribs, round bottomed 

and sometimes ornamented near the end by a faint intercalary riblet; whole surface 

of disk finely concentrically striated; hinge line slightly longer than one-half 

length of disk; ears equal, rectangularly truncated; anterior ear seulptured by 

four or five prominent. radiating ridges and . numerous fine incremental lines; byssal 

notch shallow but distinct; posterior ear with sculpture similar to anterior. Left 

valve with narrow rounded ribs, which are separated by round-bottomed and 

concave-sided interspaces much wider than the ribs; surface sculptured by fine, 

distinct, wavy, concentric lines; ears as in right valve, except lacking byssal notch. 

Hinge as in P. cattrin·u.>t. 

Dimensions.-Alt. 65 mm.; long. 65 mm.; hinge line B5 mm.; diameter 6 mm. 

The type is a smaller specimen than the average of this species. 

P. turneri is allied to the group of which P. caurinus is the commonest 

representative. Its diagnostic characteristics are its small size for one of this 

group, narrow, sulcated ribs on right valve and radially striate ears. 

Found in the Pliocene at Arroyo San Antonio, near Tomales Bay, Marin 

County, by Dr. H. W. Turner, .late of the United States Geological Survey, 

after whom it is named. 

The type, which is figured, is now in the collection of the department of 

geology, Leland Stanford Junior University. 

RANGE. 

Pliocene. Tomales Bay, Marin County (Turner). 

PECTEN (NonrPECTEN) VEATCHII Gabb. 

Pl. XL, figs. 1 and 1a. 

1869. Pecten Veatchii Gabb, Pal. Cal., vol. 2, 1869, p. 32, pl. 10, fig. 56. 

1888. Liropecten veatchii Gabb, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 246. 

1898. Pecten Veatchii Gabb, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 705. 

Description.-Shell averaging about 130 millimeters in altitude, slightly broader 

than high, subequivalve, equilateral, of medium thickness, somewhat ventricose, 

and with margins finely serrate; base regularly rounded; sides sloping above with 

slight concavity. Right valve slightly less ventricose than left, with about 8 

broad, :flat ribs arranged in pairs, and a few small linear ribs on the sides; the 
PLIOCENE PECTENS. 107 

whole surface is covered by several more or less prominent concentric undulations and numerous tine, squarish, imbricated, raised riblets; hinge line a little 

more than one-half the length of the disk; anterior ear about one and two-thirds 

length of posterior, ornamented by about 12 radiating riblets and numerous fine, 

sharp, imbricating, incremental lines; byssal notch about one-fourth length of ear 

in depth; posterior ear much smaller than anterior, but sculptured in a similar 

manner. Left -valve with about 7 broad, flat, round-cornered ridges of unequal 

size, which are separated by interspaces of unequal width, there being 3 or 5 

prominent ribs, between each pair of which is a smaller one; the surface of this 

valve is sculptured similarly to that of the right, except that the concentric . 

undulations on the ribs become more or less prominent nodes toward the apex 

of the shell; ears similar to those of the right val-ve, e~cept that the anterior 

one has a simple arcuate end and no notch. 

D imensions.-Alt. 130 mm.; long. 145 rom.; hinge line 75 mm.; diameter 

50 mm. 

This species is quite similar to and is no doubt the precursor of P. subnodosus, 

from which it differs by attaining a larger size and ha-ving fewer and broader 

ribs. Like the living form, it is quite -variable as regards the number and 

rugosity of its ribs. 

The only locality from which this magnificent species has so far been reported 

is Cerros Island, off the coast of Lower California~ where it is associated with 

P. cerrosensis, P. lecontei, Ostrea veatchii, and 0. cerrosensis in beds of probable 

Pliocene age. Doctor Cooper confused one of the large Miocene Pectens ( P. 

magnolia) with this species when he reported it from the Pliocene of Ojai 

Valley, Ventura County. (See Seventh Ann. Rept.' Cal. St. :lVIin., 1888, p. 246.) 

The specimen figured is the type, which is now in the collection of the 

Uni-versity of California. RANGE. 

Pliocene. Cerros Island, off Lower California (Dr. J. A. Veatch). 

PECTEN (CHLAMYS) BARTSCH! n. sp. 

Pl. XLI, fig. 3. 

Description.-Adult shell a-veraging about 60 millimeters in altitude, somewhat 

shorter than high, convex, slightly inequilateral; base regularly rounded; margins 

smooth. Val-ves with about 40 prominent (more or less unequal) narrow threadlike ribs, ornamented on top by numerous short imbricating spines; interspaces 

deep, narrow, and channeled; lateral areas rather narrow, perpendicular to disk, 

and slightly concave. Ears similar to those of P. islandicus. 

Dimens1:ons.-Alt 62 mm.; lat. 50 mm.; diameter 28 mm. 

This species, of which only two or three rather poorly preser-ved specimens 

are known, is quite closely related to P. opuntia, but is readily distinguishable 

by its much larger size when adult, lack of concentric constriction in the later 

stages of growth, and relatively shorter disk. 

P. bartschi is found in beds of probable lower Pliocene age at Crescent City, 

Cal., where it is associated with Tt3reb,ratalia near hmnph~~lli Dall, Phacoides 
108 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

acutilineatus Conrad, and Pecten parmeleei Dall.. The type is figured and is now 

in the U. S. National Museum, No. 164841. 

RANGE. 

Pliocene (lower). Crescent City, Del Norte County, Cal., south side of Light-House 

Point, north of wharf (Diller). 

PECTEN (CHLAMYS) BELLILAMELLArx:'US n. sp. 

Pl. XLI, figs. 6, 6a, 7, and 7 a. 

D escr-iption.-Shell averaging about- 18 n1illi'91eters in altitude, about as long 

as high, equivalve, both valves moderately convex, inequilateral; sides nearly 

straight; margins not serrate. Right valve with 15 or 16 prominent ·narrow, 

sharply convex-topped ribs with S:loping sides; interspaces much wider than 

ribs, with narrow, ·flat bottoms; surface sculptured by numerous, regular, 

equidistant, thin, concentric, imbricating lamellre, which cut squarely across the 

bottoms of the interspaces, curve convexly toward the umbo on the sides of the 

ribs, and loop gracefully downward away from tl).e umbo on the tops; hinge 

line equal to the length of the disk; ears equal in length; anterior ear convexly 

truncated, separated from the disk by a deep, sharply defined, byssal notch, and 

sculptured by fine, regular, incremental lamellre and five or six subequal radials; 

posterior ear acutely pointed, radially striate, and with incremental sculpture 

similar to but not quite as prominent as that of the anterior. Left valve similar 

to right; anterior ear more prominently sculptured, both radially and concentrically, 

than the posterior. 

Dimen8ions.-Alt. 18 mm.; long. 18 mm.; hinge 1ine 18 mm.; diameter 8 

mm. ;_ urn bonal angle 100° . 

This species is characterized by its small size when adult, long hinge line, 

narrow, sharply topped ribs and beautifully curved incremental lamellre. It is 

eaE-~ily distinguishable from P. latiauritus and varieties, with whieh it is allied, 

by the above-enumerated characteristics. 

P. bellilarnellatus is so far known only from the Pliocene at Pacific Beach, 

San Diego, where it is associated with P. healeyi, P. stearnsii, etc. Type in the_ 

collection of Delos Arnold. 

RANGE. 

PJiocene. Pacific Beach, San Diego County (Arnold). 

PECTEN (CHLAMYS) HASTATUS Sowerby. 

Pl. XLI, fig. 4; Pl. XLII, figs. 1, 1a, 2, and 2a. 

1843. Pecten hastatus Sowerby, Thes. Conch., vol. 1, 1843, p. 72, pl. 20, fig. 236 (not of Reeve, 1852= 

P. var. hericius Gld.; in part not of Carpenter, 1863; nor of Cooper, 1888). 

1857. Pecten altiplectus [typ. err.] Conrad, Proc. Acad. Nat. Sci. Phila., for 1856, 1st ser., vol. 8, 

1857, p. 313. 

1857. Pecten ctltiplicatus Conrad, Pac. R. R. Rept., vol. 7, 1857, p. 191, pl. 3, fig. 2. 

1869. Pecten hastatus Sowerby, Gabb, Pal. Cal., vol. 2, 1869, p. 104. 
PLIOCENE PEC'l'ENS. 

1887. ?Pecten hastatus Sowerby, Whiteaves, Trans. Roy. Soc. Canada, vol. 4, sec. 4, 1887, p. 119. 

1898. Pecten hastatus Sowerby, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 708. 

109 

1903. Pecten ( Chlamys) hastatus Sowerby, Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 109, pl. 11, 

figs. 4, 4a. 

1904. Pecten hastatus Sowerby, Keep, West. Am. Shells, p. 40. 

scription.~Shell averaging about 64 millimeters in altitude, slightly shorter 

than high, inequivalve, equilateral (except for ears), compressed and with serrate 

·margins; base evenly rounded below; sides slightly concave above. Right valve 

with 9 pairs of narrow, elevated, spiny ribs, along the sides of which are a pair 

of smaller spiny riblets; major interspaces much wider than ribs, conc.ave-bottomed 

and ornamented by 1 or 3 thread-like,. spiny, intercalary riblets; whole surface 

sculptured by microscopic imbricating lines, of which the spines on the ribs and 

riblets are only modifications; hinge line equal to one-half length of disk; ears 

unequal, the anterior being about two and one-half times the length of the 

posterior~ anterior ear with 7 or 8 prominently spiny radials and minor riblets, 

and imbricating incremental lines; byssal notch deep and almost as wide as ear; 

posterim; ear small, and sculptured by fine, spiny radials and imbricating incremental 

lines. Left valve with about 9 narrow, very prominently spiny ribs; interspaces 

wide, concave-bottomed, and ornamented by a single prominent, central, imbricated 

riblet~ on each side of which are minor thread-like riblets; whole surface of disk 

with fine incremental sculpture as in right valve; ears similar to those of right 

valve except that the anterior one has more ribs and riblets and no byssal notch. 

Hinge with almost ob~olete cardinal crura. Color, golden yellow to pink~ the left 

valve being the darker. 

Dimensions.--Alt. 64 mm.; long. 62 mm.; hinge line 31 mm.; diameter 22 mm. 

This beautiful species, which is the southern representative of the group of 

which var. hericius is the normal form, is characterized by the great prominence 

of the spines which adorn the major ribs of both valves. A fossil specimen of 

this species from the bryozoan Pliocene marl of Santa Barbara served as Conrad's 

type of P. altipl1~catus. (See Pl. XLI, fig. 4.) 

A variety of P. hastatu.~, found associated with the typical form in the 

Pliocene at San Pedro, Santa Barbara, and San Diego, has the strongly individualized ribs which characterize the type, but almost completely lacks the prominent 

spines. The young of this smooth form, and also of the typical spiny form, up 

to an altitude of about 15 millimeters are indistinguishable from the young of 

IIinnites gigantellS. 

Whiteaves reports P. lwstatrtts from Quatsino Sound, British Columbia. In 

describing his specimens, which were collected by Doctor Dawson, he mentions 

the few prominent ribs with a single row of high spines which characterize this 

species. RANGE. 

Living. Quatsino Sound, British Columbia (Dawson, 'Vhiteaves); Monterey (Button); San Pedro (Oldroyd, Raymond); Catalina Island (Arnold); San Diego 

(Raymond). (In all cases dredged.) 

Pleistocene (lower San Pedro formation). Bath-house Beach, Santa Barbara; 

Deadman Island, San Pedro (Arnold). 
110 TERTIARY AND QUATERNARY PECTENS OF CALU'ORNI.A. 

Pliocene. Packard's hill, Santa Barbara (Yates, Wilson, Bowers, and Arnold); 

Ventura County (Bowers); Deadman Island, San Pedro (Mrs. A. E. Bush, 

Voy, WHson, Oldroyd, Williamson, Arnold, and others); Temescal Canyon, 

Santa Monica Mountains, Los Angeles County . (Rivers); Pacific Beach, San 

Diego (Arnold). 

PECTEN (CHLAMYS) HASTATUS Sowerby var. HERICIUS Gould. 

Pl. XLIII, . figs. 3 and 3a. 

1850. Pecten hericius Gould, Proc. Bost. Soc. Nat. His., vol. 3, 1850, p. 345. 

1852. Pecten hericius Gould, Wilkes Expl. Exped., vol. 12, 1852, p. 457, fig. 570 . 

• 1852. Pecten hastatus Reeve (not of Sower by), Conch. Icon., vol. 8, pl. 11, fig. and sp. 43. 

1863. Pecten hastatus Carpenter (not of Sowerby), Brit. Assn. Rept., 1863, p. 645 (in part). 

1888. Pecten hastatus Kiister and Kobelt (not of Sowerby, 1843), Conch.-Cab., vol. 17, pt. 2, sp . . 

210, ·p. 233, taf. 62, figs. 1 and 2. 

1888. Pecten hastatus Cooper (not of Sowerby), Seventh Ann. Rept. Cal. St. Min., 1888, p. 257 (in 

part). 

1898. Pecten ( C'hlarnys) hericeus Gould, Dall, Trans. 'Vagner Free Inst. Sci., vol. 3, pt. 4, 1898, 

p. 708. 

1903. Pecten ( Chlarnys) hericeus Gould, Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 110, pl. 11, 

fig. 2. ' 

1904. Pecten hericeus Gould, Keep, West. Am. Shells, pp. 39-40, fig. 19. 

Descrption.-Adult shell averaging about 70 millimeters in altitude, not 

quite. as long as high, both valves compressed, equilateral (except for ears), 

which are decidedly unequal; margins finely serrate; sides markedly concave 

above; umbo acute. Right valve with . 9 or 10 pairs of spiny fasciculi, the 

middle rib of each fascicule being the most . prominent; interspaces about as wide 

as the fasciculi, and ornamented by several more or less spiny riblets; spaces 

between the riblets of the fasciculi and large interspaces channeled and ornamented 

by fine imbricating incremental lines, but free from any reticulations whatever; 

hinge line a little over one-half the ·length of the disk; anterior ear about two 

and one-ha1f times longer than the posterior, ornamented by imbricating concentric 

lines, and above the notch by several subequal spiny riblets; byssal notch wide 

and d~ep; posterior ear small, and ornamented by numerous fine spiny riblets. · 

Left valve with about 9 or 10 elevated fasciculi, the middle rib of each 

fascicule being quite prominently spinose; the spaces between the mttjor fasciculi 

each occupied by a minor fascicule of more or less scaly riblets; interspaces 

between the riblets channeled and with imbricating incremental sculpture; ears 

sculptured as in right valve except that the riblets are smaller and more numerous 

on the anterior ear. Hinge weakly developed. Color pink to greenish, left 

valve the darker. 

Dimens£ons.-Alt. 73 mrn.; long. 65 mm.; hinge line 34 mm.; diameter 21 mm. 

This variety appears to be the normal form of the group of J->. hastatus, the 

.typical hastatus having the imbricating spines on .the ribs extremely developed. 

The only difference between P. hastatus and this variety is in the relative prominence and abundance of the ribs and riblets forming the fasciculi. In the right 

valve of the adult var. hericiur~ each faseicule consists of three ne~rly equal spiny 
PLIOCENE PECTENS. 111 

riblets (the middle riblet of the three being slightly m~He prominent and spiny), 

between which and the middle riblet of the adjoining interspace are two small 

riblets (and sometimes another still smaller .pair of intercalaries), while in the 

adult P. hastatus the fascicular arrangement on the right valve is obscure, there 

being a central spiny rib with 2 and sometimes 4 faint scaly riblets between 

the major rib and the middle riblet of the interspace. The fasciculi of the left 

valve of P. hericius are convex, and consist of a central more or less spiny rib, 

between which and the middle riblet of the fascicule of the interspace are about 

9 to 12 thread-like scaly riblets; while in P. hastatttS there is a high narrow rib 

with steeply sloping sides, having a top ornamented by numerous taJl curved 

spines; between this rib and the rib running down the interspace are from three 

to five faint thread-like scaly riblets. 

P. var. hericitts ranges from the Miocene (Santa Margarita formation) to the 

Recent fauna. The fossil forms average smaller, and appear to have slightly more 

scaly secondary riblets, but in all other respects they are identical · with the ~iving· 

shells. 

A single specimen of Pecten, closely allied to if not identical with P. var. 

her·ie1.:us, was found associated with P. estrellanus Conrad, Ostrea palmula Cpr., 

Tamiosoma gregaria Conrad, OhoPus belcheri Hinds, and Astrodapsis t·umidus 

Remond, near San Lucas, Monterey County. 

The type of P. hericius is from the Strait of ~T uan de Fuca, off the north 

coast of Washington, and is now in the U. S. National lVluseum (No. 5955). 

RANGE. 

Living. Puget Sound (Dall, Carpenter, Button). 

Pleistocene (lower San Pedro formation). Deadman Island, San Pedro (Arnold). 

Pliocene. Temescal Canyon, Santa Monica Mountains, Los Angeles County 

(Rivers); Deadman Island, San Pedro (Voy, Arnold); Pacific Beach, San 

Diego (Hemphill, Arnold). 

Miocene (upper). San Lucas, Monterey County (Hamlin, Arnold). 

PECTEN (CHLAMYS) HASTATUS Sowerby var. HINDSII Carpenter. 

Pl. XLIII, figs. 1, 2, and 2a. 

1863. Pecten hastatus (? var.) hindsii Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1887. Pecten hericeus var. hindsii Carpenter, \Vhiteaves, Trans. Roy. Soc. Canada, vol. 4, sec. 4, 1887, 

p. 119. 

1898. Pecten hericeus var. hindsii Carpenter, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, 

p. 709. 

Descrption.-Shell smaller than P. var. hericius, averaging about 5B millimeters 

in altitude; shape and convexity as in var. hericius; margins smooth. Right valve 

with about 26 close-set, sometimes wide, flattish, usually dichotomous, smooth ribs, 

which show fine lines of growth on their surface; interspaces narrow, channeled, 

and sculptured by minute reticulations; hinge line one-half as long as disk; anterior 

ear produced, sculptured by about six radials and prominently imbricating concentric 
112 TERTIARY AND QUATERNARY PECTENB OF CALIFORNIA. 

lines; byssal notch prominent; posterior ear small and with radials and imbricating 

concentric sculpture. Left valve with small, obscurely fasciculated, imbricated ribs, 

each fascicule having one major and several much smaller and more prominently 

imbricated riblets; interspaces very narrow and sculptured as in right valve; ears 

similar to those of right valve except lacking notch in anterior one. Color pink to 

white, the left valve being the darker. 

D£mensions.-Alt. 58 mm.; long. 57 mm.; hinge line 29 mm. ~ diameter 18 mm. 

Doctor Dall, in mentioning this variety, says :a "The typical specimens seem 

remarkably distinct from P. Aericeus var. navarchus, but in a large series intergradation is obvious." Carpenter in his original description mentions that var. hindsii 

• • passes from lwstatus toward islandz"crus." 

RANGE. 

Living. Bering Sea to Monterey (Dall); Victoria, B. C. (Button); Quatsino Sound 

and vicinity of Vancouver Island (Dawson; Whiteaves). 

Pleistocene. Sucia Island, Puget Sound (Newcombe). 

Pliocene. Deadman Island, near San Pedro (Arnold). 

PECTEN HASTATUS Sower by var. NA VARCHUS Dall. 

Pl. XLIII, figs. 1, la, and lb. 

1844. Pecten rubidtt,S Hinds, Zool. Voy. Sulph., 1844, p. 61, pl. 17, fig. 5 (not P. rubidus Martyn, 

1784). 

1898. Pecten hericeus var. navarchus Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 708. 

1904. Pecten rubidus Hinds, Keep, West A.m. Shells, p. 40. 

D escription.-Shell averaging about 55 millimeters in altitude, higher than 

long, subequivalve, both valves only slightly ventricose, thin, sides only slightly 

concave above. Right valve light colored, less ventricose than left, with numerous 

small, subangular, flat-topped, dichotomous, and slightly imbricated ribs~ surface 

obscurely tessellated; anterior ear quite prominent, with about 6 prominent 

radiating· ridges and numerous imbricating incremental lines; byssal notch of 

medium size; posterior ear small, with distinct radial ridges and imbricating 

sculpture. Left valve reddish or pinkish, more ventricose than right, with 

numerous small fasciculated and quite prominently imbricated ribs, each fascicule 

having one prominent rib in the middle with lesser ones on the sides; the major 

interspaces occupied by a small riblet; ears as in right valve except lacking 

byssal notch. Margins not prominently serrate. 

Dimensions.-Alt. 55.5 mm.; long. 54 mm.; hinge line 21 mm.; diameter 

17 mm. 

This variety is smaller and more delicate than P. islandicus, and has fasciculated rather than dichotomous ribs on the left valve. 

RANGE. 

Living. Aleutian Islands southward to Lower California (Dall); Kodiak Island, 

Alaska (Greeley and Snodgrass). 

a Op. cit., p. 709. 
PLIOCENE PECTENS. 113 

Pleistocene. Bowlder clay of Oomox, Vancouver Island (Newcombe). 

Pliocene. Deadman Island, San Pedro (Dall, Stearns); Timms Point, San Pedro 

(Arno1d); Pacific Beach, San Diego (Hamlin). 

PECTEN (CHLAMYS) HASTATUS SowERBY var. STRATEGUS Dall. 

Pl. XLIV, 2, 2a, 3, and 4. 

1898. Pecten hericeus var. strategus Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 709 

1903. Pecten ( Chlamys) hericeus var. strategus Dall, Arnold, Mem. Cal. A cad. Sci., vol. 3, 1903, p. 

110, pl. 11 , fig. 5 (right valve of a young specimen figured). 

D escription.-Adult shell averaging about 35 millimeters in altitude, slightly 

higher than long, inequivalve, equilateral, except for ears; both valves nearly 

flat up to an altitude of about 22 millimeters, where they generally become more 

convex by contraction, and the sculpture becomeg more complicated. Right valye 

with 9 to 12 prominent, subequal, broad, nearly flat-topped, usually dichotomous, 

turgid ribs, with sometimes smaller intercalary riblets, all of which break up 

more or less suddenly into fasciculi of two or more rihlets upon reaching an 

altitude of about 22 millimeters; interspaces subequal, broad, and channeled; 

whole surface of disk and ribs microscopically tessellated; hinge line equal to 

about one-half length of disk; anterior ear much produced, and sculptured 

by fine imbricating incremental lines and about 6 radial ridges; byssal notch 

prominent; posterior ear nearly obsolete, sculptured similarly to right. Left 

vah·e resembling the right except that the ribs are narrower, more convex, and 

with the intercalary riblets usually more imbricated; interspaces broader than in 

right valve; anterior ear with about 8 imbricated ridges. Color of recent specimens 

bright scarlet. 

D imensions.--Alt. 35 mm.; long. 34 mm.; hinge li~e 17 mm.; diameter 16 

mm.; umbonal angle 83 mrn. 

This variety is easily distinguished by its few broad ribs, which increase in 

number very rapidly both by division and intercalation after reaching an altitude 

of about 20 mill~rneters. Some of the · Pleistocene (lower San Pedro formation) 

specimens from San Pedro retain a pinkish color. 

RANGE. 

Living. Unalaska (Dall). . 

Pleistocene·. Alaska (Dall); Dendman Island, San Pedro (Arnold); Bath-house 

Beach, Santa Barbara (Arnold). 

Pliocene. Packards Hill, Santa Barbara (J. H. Wilson). 

PECTEN (CHLAMYs) rsLANDrcus Muller. 

Pl. XLV, figs. 1 and la. 

1776. Ostrr.ea Islandicus Muller, Prodr. Zool. Dan., No. 2990, p. 248. 

1778. Pecten cinnabarina Born, Mus., p. 103. (Fide Dall, 1898.) 

1780. Ostrea Islandica Muller, Fabricius, Fauna Gronl., p. 415. 

1784. Pecten lslandicus Muller, Chernnitz, Conch., vol. 7, p. 304, pl. 65, figs. 615 and 616. 

1784. Pecten rubidus Martyn, Univ. Conch., vol. 2, pl. 153, fig. 1. 

1797. Ostrea demissa Solander, Museum Colonnianum, p. 52, No. 986. 

17260-No. 47-06-8 
I 

I 

114 TERTIARY AND QUATERNARY PEOT}~NS OF lJALIFORNIA. 

1831. Pecten Pealei Conrad, Amer. Mar. Conch., p. 12, pl. '2, fig. 2. 

1836. Pecten Islandica Muller, Lamarck, Anim. Sans. Vert., ed. 2, vol. 7, p. 145, No. 42. 

1843. Pecten Islandicus Muller, Sowerby, Thes. Conch., vol. 1, Pecten, figs. 159-161. 

1844. Pecten Fabricii Philippi, Abbild. und Beschreib. Conchyl., vol. 1, p. 101, pl. 1, fig. 5. 

1853. Pecten Islandicus Mii.ller, G. 0. Sars, Moll. Reg. Arcticre Norvegire, p. 16, pl. 2, fig. 2. 

1888. Pecten islandicus Muller, Kuster and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondylus und Pecten, 

No. 24, p. 59, taf. 16, figs. 1 and 2. 

1888. Pecten islandicus Chemnitz, Kuster and Kobelt, op. cit., p. 105, taf. 30, figs. 1-6. 

1888. Not Pecten islandict£i Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 257 ( = P. jordani 

Arnold,. 1903). 

1897. Chlamys islandica (Chemn. ), Verrill, Trans. Conn. Acad. Sci., vol. 10, June and July, 1897, p. 

72, pl. 16, figs. 2-5b; pl. 20, fig. 9; pl. 21, fig. ~. 

1898. Pecten ( Chlamys) islandicus Muller, Dall, Trans. \V agner Free Inst. Sci., vol. 3, pt. 4, p. 708. 

1901. Pecten islandicus Muller, Brogger, Norges Geol. Undersogelse, No. 31, p. 228, fig. 23, tab. 5, figs. 

1, a, b, c, and d. 

· Description.-Shell averaging about 80 millimeters in altitude, .subcircular, 

somewhat higher than long, subequivalve, both valves only slightly convex, equilateral, except for ears; of medium thickness; sides only slightly concave above; 

base evenly rounded; color of living shell pinkish to salmon, the left · valve being 

the more highly colored. Right valve with numerous narrow, square, flat-topped, 

imbricated ridges, which multiply ~lowly, both by division and intercalation, as the 

shell grows; interspaces narrow, channeled, and minutely . reticulated; hinge line 

equal to more than one-half length of disk; anterior ear much produced, sculptured by numerous sharp imbricating lines and 5 or 6 major radiating ridges and 

some intercalaries; byssal notch quite prominent; posterior ear a little over onehalf as long as the anterior, and sculptured in the same way. Left valve similar 

to right, except possibly that the imbrication is a little more pronounced. 

Dimensions.-Alt. 83 mm.; long. 77 .mm.; hinge line 44 mm.; diameter 27 mm.; 

apical angle 84° . 

This species is characterized by its large size when adult, large number of 

subequal scaly ribs, reticulated, channeled interspaces, and the relatively long 

posterior ear for a mem her of this group. 

Only two authentic specimens of this species are known from California; 

both are from the Pliocene of Deadman Island, San· Pedro, one bemg in the V oy 

collection at the University of California and the other in the collection of Delos 

Arnold. RANGE. 

Living. North Atlantic; Bering Sea (Dall). 

Pleistocene. Bowlder clays of the northwest American coast, Alaska, and British 

Columbia (Dall). 

Pliocene. Deadman Island, San Pedro (Voy, Arnold)._ 

PJWTEN (CHLAMYS) JORDAN! Arnold. 

Pl. XLIV, figs. 1, la, and lb. 

, 1903. Pecten ( Chlamys) jordani Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 111, pl. 12, figs. 6 and 7. 

Description.-Shell shape of I.>. islandicus, averaging about 45 millimeters in 

altitude, somewhat shorter than high, inequivalve, both valves convex, equilateral 
PLIOCENE PECTENS. 115 

except for ears, rather thin, and with smooth margins. Right valve vvi.th about 

25 to 30 angular smooth-topped, imbricated ribs, whieh become dichotomous after 

reaching a length of about 30 millimeters; interspaces deeply channeled and 

narrower than ribs; anterior ear imperfectly radially ribbed with 6 ridges, and 

showing elevated, concentric incremental lines; posterior ear nearly obsolete, 

showing about 4 ribs; byssal notch not deep. Left valve with 25 to 30 narrow, 

convex ribs, showing imbricating sculpture only slightly; interspaces as wide as or 

wider than ribs; after a diarneter of 30 millimeters has been reached by the left 

valve small intercalary ribs appear in most of the widening interspaces; anterior 

ear with 5 narrow, imbricated ridges separated by wide interspaces. Both valves 

show a tendency to contract suddenly at the basal margin upon nearing completion of growth; surface of both valves covered with a minute lattice-like sculpture, which is generally worn off on exposed portions of the shell. 

Dimensions.-Alt. 45 mm.; long. 42 mm.; hinge line 18 mm.; diameter 15 mm. 

This species is allied to the group of which P. ,islandimts is the type. 

Although distinctly separated from the other members of the group, it is, nevertheless, quite closely related to P. lwstattts var. navaTchus and var. /1,indsii. 

The right valves of P. jordani and of the two varieties above mentioned are 

very similar, but the left valve of P. jordani is entirely different from that of 

the other two, having simple, lattice-like sculptured ribs instead of imbricated, 

fasciculated ones. P. jordani is distinguishable from P. hastatus, and the latter's 

variety heridus by its lack of fasciculated ribs. No gradation between 1). jordani 

and other members of the group has been noticed by the writer, whereas in 

nearly all the other cases a large series shows obvious intergradation between 

the difl'erent forms. • 

I). jordani is found in both the Pliocene and lower Pleistocene, but is not 

known as living. 

RANGE. 

Pleistocene (lower San Pedro formation). Deadman Island, San Pedro; Santa 

Barbara (Arnolrl). 

Pliocene. D~eadman Island, San Pedro (Bush, Wilson, Oldroyd, Arnold); Santa 

Barbara; Pacific Beach, San Diego (Arnold). 

PECTEN (CHLAlVIYS) LATIAURITUs Conrad. 

Pl. XL VI, figs. 2, 2a, 3, and 3a. 

1837. Pecten latiauritus Conrad, Jour. Acad . .Nat. Sci. Phila., vol. 7, 1837, p. 238, pl. 18, fig. 9 

1842. Pecten latiauratus Conrad, Sowerby, Thes. Conch., vol. 1, pt. 1, 184?, p. 57, pl. 12, figs. 

20, 21. 

1844-1847. Pecten tunica Philippi, 1844;+ P. rnesotirneris Sowerby, 1847 (fide Dall, 1898). 

1852. Pecten latiauritus Conrad, Reeve, Conch. Icon., vol. 8, 1852, ·pl. 1, fig. 5. 

1863. Pecten latiauritus Conrad, Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1888. Pecten latiauritus Conrad, Kiister and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondylus und 

Pecten, No. 163, p. 203, taf. 54, figs. 7 and 8. 

1888. Pecten latiaurittts Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 257. 

1892. Pecten latiauritus Conrad, Keep, West Coast Shells, 1892, p. 167. 
116 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

1892. Pecten latiau1·itus Conrad, .Williamson, Proc. U. S. Nat. Mus., vol. 15, 1892. p. 193. 

1898. Pecten ( Chlamys) latiauritus Conrad, Dall, Trans. w·agner Free Inst. Sci., vol. 3, pt. 4, 1898, 

p. 709. 

1903. Pecten (Chlamys) latiauritus Conrad, Arnold, Mem. Cal. Acad. Sci., vol. 3, pt. 2, 1903, p. 

111, pl. 12, figs. 2 and 2a. 

1904. Pecten latiimritus Conrad, Keep, West Am. Shells, p. 40. 

Description.-Shell averaging about 25 millimeters in altitude, about as long 

as high, inequivalve, compressed, inequilateral, disk obliquely produced posteriorily, thin; sides straight; margins smooth. Right valve more compressed than 

left, with 12 to 16 low, rather squarish ribs, separated by equal, more or less 

distinctly channeled interspaces; whole Rurface sculptured by numerous fine concentric lines; hinge line nearly as long as disk; ears subequal in length; anterior 

ear long and narrow, with 5 or 6 prominent radials and numerous fine concentric 

lines; byssal notch deep and distinctly separating ear from disk; posterior ear 

from rectangularly to acutely pointed, sculptured by obsolete radials and concentric lines. Left valve . somewhat more convex than right, otherwise similar to it; 

anterior ear generally shorter and more pr<i>minently sculptured than posterior. 

Dim.ension8.-Alt. 25 mm~; long. /23 .mm.; hinge line 20 mm.; diameter 9 mm.; 

umbonal angle 90°. 

This species is characterized by its small ·size, oblique disk, thinness, long 

hinge line, and deep byssal notch. The sculpture of the shell is usua_lly well 

marked. The ribs are ~ometimes faintly medi_ally sulcated, and the interspaces 

sometimes contain a faint intercalary riblet in· the later stages of growth. The 

Pleistocene shells, as a rule, are rather more strongly ribbed than the living. 

A pair of valves in the U. S. National Museum (No. ~6964), from U. S. 'Fish 

Commission Station No. 2840, Santa Barbara Islands, is labeled B P. tltmbezensis 

Orb." This shell is probably an albino variety of P. latialtritus, having just a 

touch of color on the interior of the posterior ear of the left valve. The true 

P. twnbezensis is from the Peruvian part of the South American coasts. 

In the Third street tunnel, Los Angeles, P. latiauritus has been found associated with the · follo.wing fauna: Pecten pedroanus, P. ashleyi, P. opuntia, P. 

stearnsii, Glyph is densiclathrata, 1Vassa n. sp. ? , .Macmna sp. indet., Area multicostata, Lima h.amlini, Bucci'num sp. indet., Neverita recluziana, Astarte sp., Priene 

oregonensis, Ostrea veatchii, Plmtrotoma sp. indet., and a carditoid. As this fauna 

1 indicates a horizon well down in the Pliocene,. it extends the geologic range of 

P. latiauritus much further back than heretofore known. 

P. latiauritus is found living attached to kelp, those specimens inhabiting 

the deeper, quieter waters being less strongly sculptured than those which are 

subjected to a more strenuous existence nearer the shore. 

RANG~. 

Living. Monterey (Yates); Santa Barbara to San Diego (Carpente'r and others). 

Pleistocene. Santa Barbara; San Pedro (Cooper); San Pedro; San Diego (Arnold, 

Wilson, Dall). · 

Pliocene. Third street tunnel, Los Angeles (Hamlin). 
PLIOCENE PECTENA. 117 

PECTE~ (CHLAMYS) LAWSO~I n. sp. 

Pl. XLV, figs. 3 and 4. 

Descr1;ption.-Adult shell averaging· about 70 millimeters in altitude, not as long 

as high, inequivalve, only slightly convex, equilateral, ears unequal; base regularly 

rounded; sides only slightly concave above; margins somewhat serrate. Rig-ht valve 

with about 18 to 20 subequal, prominent, narrow, round-topped, rugose ridges, separated by somewhat wider interspaces, in each of which runs a single more or less 

rugose riblet; some of the ribs are' oceasionally medially sulcated or dichotomous; 

surface sculptured by numerous irregular incremental lines, which give the ribs a 

squamose appearance when they are unworn~ ears unequal, the anterior with three 

or four rather prominent rugose radials and numerous incremental lines; the posterior with several less prominent radials, and incremen~al sculpture; byssal notch 

rather profound. Left valve with 9 or 10 prominent narrow, round-topped, rugose 

major ribs, between each two of which there is a single minor rib similar to and 

almost equaling in prominence the major ribs; a single thread-like intercalary is 

visible in most of the interspaces; · surface sculptured as in the right valve; ears 

similar to those of right valve except that there is no prominent notch between the 

anterior one and the disk. 

Dinwnsions.-Alt. 70 mm. ~ long. 81 mm.; diameter 24 mm.; umborial angle 87° . 

This species is closely allied to ]>. hastatcus, but is distinguishable by the paucity 

of its secondary sculpture (such as spines and secondary intercalaries), the nearly 

equal prominence of the major and minor ribs in the left valve, and the equality 

of the interspaces in the right. (The ribs in the right valve of 1). hastatus occur in 

pairs, each pair being separated from those adjacent by spaces perceptibly wider 

than the interspaces. between the members of each pair.) The smooth variety 

of P. hastatus mentioned as occurring in the Pliocene at San Diego, San Greg-orio, 

etc., appears to occupy a position n.bout midway between the typical P. hastatus 

and ].J. lawsoni. 

The type of 1). lawsoni, which is now in the collection of the California Academy 

of Sciences, was collected by J\'Ir. F. M. Anderson from the Pliocene at the Waldorf 

asphalt mine, 4 miles south of Guadaloupe, Santa Barbara County. Mr. Anderson 

has kindly furnished the following list of fossils from the beds at this mine: Orepidula p rinceps Conrad, Tttrritella cooperi Carpenter, Bitti~tm. asperum Gabb, Priene 

oregonen.rsis Redfield, Trochitct costellata Conrad, Lunat·ia lewisi-i Gould, Ncttica sp., 

Oallio8tO?na genvnulat1..an Carpenter, Scala sp., 1Vassa perpinguis Hinds, Pleurotoma 

near carpenterianr.l Gabb, Pleurotorna near tryordana Gabb, Pyrula ( ?) sp., Drillia 

torosa Carpenter, Purpu1Yt crispata Chemnitz, Oolttmbella richthofeni Gabb, Dentaliwn sp., Acuu:ea sp., _Panopea generosa Gould, L eda taphria Dall, Area 2 sp., Venericardia ventricmsa Gould, Pandorct scapha Gabb, Tellinct sp., P ecten 2 sp., J1!artesia 

ovoides GQuld, Phacoides ( + L ·ucina) near acutil-£neatus Conrad, Phacoides sp., 

_1lfctcorna sp., _1}£ytilns sp., Ost·rea sp., Echinarachnius sp., and coral. 

The writer is also indebted to Mr. Anderson for the following list of fossils from 

a locality 1 mlle north of Schumann switch, (3 miles east of the Waldorf asphalt 

mine), Santa Barbara County: Trochita near costellata Conrad, Trochita near 
118 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

inornata Gabb, Oalliostoma sp., Lttnatia lewisii Gould, Glycy1neris (+ P ectunculus) 

near patuVu...<? Conrad, Glycymeris sp., Venericardia ventricosa Gould, Pecten lawsoni 

n. sp., Pecten ash1eyi n. sp., etc. ' 

Named in honor · of Dr. A. C. Lawson~ ·professor o£ geology at the University 

of California. 

RA-NGE. 

Pliocene (lower). Waldorf asphalt mine, 4 miles south of Guadaloupe, and 1 mile 

north of Schumann switch, Santa Barbara County (F. M. Anderson). 

PECTEN (CHLAlVIYS) OPUNTIA Dalt· 

Pl. XLI, fig. 2. 

1898. Pecten ( Chlarnys) opuntia Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 707, pl. 29, 

fig. 6. 

1903. Pecten ( Chlctmys) opuntia Dall, Arnold, Mem. Cal. Acad. Sci., vol. 3, 1898, p. 113. 

· D escription.-Shell averaging about 35 millimeters in altitude, slightly shorter 

than high, subequivalve, equilateral (except for ears), both valves nearly flat until 

altitude of ~bout 20 to ~5 millimeters is reached, . when they grow more convex; 

contracted at basal margin when adult; sides only slightly concave above. Right 

valve with 40 to 60 subequal, narrow, imbricated, more or less dichotomous ribs, 

which are separated by channeled interspaces about equal in width to the ribs; 

hinge line about two-fifths as long as disk; anterior ear muc.h produced, sculptured 

by about six prominent, sharply imbricated radials, . and imbricating incremental 

lines; byssal notch quite prominent; posterior ear nearly obsolete, radially and 

concentrically sculptured; whole surface of disk and ears sometimes microscopically 

checkered or tessellated. Left valve similar to right. 

D·im.ensions.-Alt. 43 mm.; long. 40 mm.; hinge line 16 mm.; diameter 12 mm.; 

umbonal angle 78° . 

This species is allied toP. hastatus var. navarchus, from which it differs by its 

smaller and not fasciculated radial ribs, more elongated anterior ear, more densely 

radially costate posterior ear, small size when adult, and by a tendency to be 

suddenly contracted at the basal margin on the completion of growth. P. op'Mntia 

is distinguishable from other men hers of this group by its large number of nearly 

equal thread-like ribs and small umbonal angle. 

RANGE. 

Pliocene. Pacific Beach, San Diego (Hemphill; · Hamlin; Arnold); Packard's Hill, 

Santa Barbara (J. H. Wilson, Arnold); Rincon Creek, Santa Barbara County 

(Watts); Third Street tunnel, Los Angeles (Hamlin); Temescal Canion, Santa 

Monica Mountains, Los Angeles County (Rivers). 
PLIOOENE PECTENS. 119 

PECTEN (CHLAJUYS) PARJUELEEI Dall. 

Pl. XLI, figs. 1, 1a, 5, and 5a. 

1898. Pecten ( Chlamys) Parmeleei Dall, Trans. 'Vagner Free Inst. Sci., vol. 3, pt. 4, p. 708, pl. 37, 

figs. 14 and 14a, 1898. 

Description.-Shell averaging about 50 millimeters in altitude, somewhat 

shorter than high, rather compressed, inequivalve, equilateral; ears unequal. 

Left valve with 5 prominent, narrow, smooth, and convex-topped ribs, separated 

by much wider interspaces which are sculptured by numerous, rather fine, radial 

riblets; whole surface of disk covered by profuse, coalescent, microscopically 

checkered squamation; anterior ear produced and ornamented by several small 

radials and microscopic sculpture; posterior ear short, but otherwise as . anterior. 

Right valve similar to the left, except that the ribs, which in the right valve correspond to the interspaces of the left, are much broader than -those of the left; 

interspaces relatively narrower. The disks' of both valvesare constricted at irregular 

intervals, which tends to give the ribs a nodose appearance. 

Dirnensions.-Alt. 45 mm.; long. 38 mm. 

This species is close toP. swiftii Bernhardi, of ~Japan, but smaller, and differs 

by the smooth top surface of the ribs, which in P. swiftii are more or less 

striated or coarsely threaded, and by the not alternated radial riblets on the ]eft 

anterior ear; also, especially, by the peculiar microscopic squamation which makes 

a complete external coating to the valve. P. parmeleei differs from P. wattsi hy 

its narrower ribs on the left valve, finer radials in the interspaces, less prominent 

constrictions of the disk, and peculiar microscopic sculpture. 

Only two specimens of this species have so far been found: a left valve (the 

type, U. S. N. M. 154479) from the Pliocene at Pacific Beach, near San Diego, 

and an imperfect right valve (U. S. N. M. 164842) from the Pliocene at Crescent 

City, Cal. 

RANGE. 

Pliocene. Crescent City, Del Norte County, south side of Light-House Point, north 

of wharf (Diller); Pacific Beach, San Diego (Parmelee). 

PECTEN (CHLAMYS) WASHBURNE! n. sp. 

Pl. XLV, fig. 2. 

Descr1ption.-Shell averaging over ·100 millimeters in altjtude, somewhat 

shorter than high, subequivalve, equilateral (except for the ears), rather thin; 

base regularly rounded; sides somewhat conca:ve above. Left valve with about 

65 more or less unequal, faintly squamose, low, squarish ribs; interspaces about 

as wide as the ribs, and sometimes ornamented by an intercalary thread or riblet; 

whole sur.face of disk ornamented by imbricating lamellre; anterior ear somewhat 

convex in front, and with a faint suggestion of .a notch, ::~culptured by about 12 

rather low imbricated radials; posterior ear about one-half as long as the anterior, 

obliquely truncated, and ornamented by faint radials and imbricating lamellre. 

/' 
I 

120 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

Right valve unknown, but, judging .by the affinity which this species bears to 

P. islandicus, it should be similar to the left valve, with the exception that the 

anterior ear should have a deep byssal notch, and the ribs should be slightly 

broader and the interspaees corre::;pondingly narrower. 

Dimensions.-Alt. 110 mm.; long. about 100 mm.; hinge line about 50 mm.; 

diameter 30 mm. 

This species is closely allied to P. islandimtS, and may be its direct precursor. 

It is distinguishable· from the latter, however, hy its larger size (being the largest 

species of this group yet known from the Pacific coast), more numerous, lower, 

and smoother ribs, and less obliquely tr~ncated posterior ears . 

. P. wasAburnei occurs in beds on the Yachates River, Lincoln County, Oreg., 

where it is associated with the following fauna: Opalia condoni Dall, Terebratella 

t1·ansversa Sby, A emma; sp., Strongylocentrotus (cf) purpuratus Stimpson, (Jidari8 

(?) sp., Natica or,Neverita sp., Buccin~t?n (?) sp., Calliostoma sp. Doctor Dall is 

of the opinion that these beds are the -equivalent of · those at Eugene, Oreg., of 

whose position in the stratigraphic column there is much uncertainty. Tentatively, 

however, this species will be placed with those from the lower Pliocene. · 

This species is named in honor of Mr. Chester Washburne, of Eugene, Oreg.", 

whose work in the Oregon Tertiary has added many new species to the lists. 

The type is now in the U. S. National :Museum (No. 164843), locality 3593. 

RANGE. 

Pliocene (lower?). Yachates River, Lincoln County, Oreg. (Washburne) 

PECTEN (CHLAMYS) WATTSI n. sp. 

Pl. XI, figs. 1 and la. 

Description . ..,-Shell averaging about 65 millimeters in altitude, slightly higher 

than long, equilateral, of medium thickness, decidedly ventricose, and with margins 

slightly finely serrate; base regularly rounded; sides sloping above, with slight 

concavity. Left valve with 5 high, rather narrow, rounded, almost smooth ribs, 

which are made prominently nodose by several very pronounced concentric undulations, or constrictions; interspaces much wider than ribs and each ornamented by 

about 5 small, subequal, rounded, imbricated riblets; whole surface of disk with a 

profuse, coale~cent, microscopically checkered squamation; hinge line about twofifths length of disk; anterior ear with arcuate end, and with surface sculpt_ured by 

about 5. prominent imbricated riblets and several concentric undulations; posterior 

ear obsolete. Right valve about equal to left in convexity, with broad, flat-topped 

ribs and · narrower interspaces, both being longitudinally sculptured by subequal 

riblets; eai·s similar to left; byssal notch not prominent; surface sculpture microscopic; constrictions less pronounced than in left valves. 

Dimension8.-Alt. 67 mm.; long. 59 ~m.; hinge line 20 mm.; diameter 36 mm. 

This species is even more · closely allied to P. swiftii Bernhardi (J out. de 

Conch., voL 7, 1858, p. 90, pis. i and ii), of Japan, than is P. parmeleei. It is 

distinguishable from P. swiftii, however, by its broader ribs, not alternated 

radial riblets on the right anterior ear, and by the smaller number of secondary 

\ . 
PLIOCENE PECTENS. 121 

r1blets in the wide interspaces. The specimens of P. wattsi are too poorly 

preserved to show satisfactorily the microscopic sculpture of the surface, but 

what is left of this sculpture appears to be very much like that of ]"->. swiftii. 

P. wattsi . differs from P. parn1eleei in having broader and more strongly 

nodose ribs, more numerous (6 instead of 4) radials on the anterior ear, and 

most of all by the fewer and much larger-sized secondary radial riblets in 

the major interspaces. The poor state of preservation of the type of P. wattsi 

precludes any definite statements regarding its microscopic surface seulpture, but 

from as good a comparison as could be made under the circumstances the two 

species appear to have somewhat different kinds. 

P. wattsi is found in heds near Kreyenhagen's ranch, Fresno County, which 

are supposed to be of lower Pliocene age. It has been collected from beds of 

lower Pliocene age (Purisima formation) on Pescadero Creek, San Mateo County, 

and at other localities in the southern part of the State. At Olinda, Puente Hills, 

Orange County~ Mr. Eldridg·e found P. wattsi associated with P. asl~leyi, 

P. aubu1·yi, P. oweni var., Priene (ajf.) oregonensis, Cardium (cf.) quad1·igenariwn, _Neverita recl!uzianct, Phacoides californicus, and Fusus (cf.) barbarens£s, in 

beds of probable lower Pliocene age. 

The type is from Kreyenhagen's ranch, Fresno County, and is now in the 

collection of the California Academy of Sciences. It is named in honor of 

J\1r. " 7

• L. vVatts, whose collec.ting has added very materially to the list of west 

coast fossil Pectens. RANGE. 

Pliocene (lower). Pescadero Creek, one-fourth mile above fJones Gulch, San Mateo 

County (Newsom; Arnold); Kreyenhagen's ranch, Fresno County ("fatts); 

Olinda, Puente Hjlls, Orange County (Eldridge). 

PECTEN (CHLAMYS) WATTSI var. MORANI n. var. 

Pl. X, figs. 3, 4, 5, and 6. 

Descrption.-Adult shell averaging· about 65 millimeters in altitude, much 

shorter than high, inequivalve, equilateral, moderately convex, and with slightly 

serrate D?-argins. Right valve less convex than the left, ornamented by 4 very 

broad, prominent, flat-topped ridges, each of which carries from 5- to 7 strong, 

squarish, elevated, subequidistant riblets; interspaoes narrow and rather deep, each 

ornamented by 1' or 2 squarish riblets; hinge line about one-third length of disk; 

anterior ear much more prominent than the posterior, regularly arcuate-ended and 

sculptured by 5 or 6 radials; byssal notch only sligl;ttly developed; posterior ear 

very short, obliquely truncated and radially striate. Left valve more convex than 

right, and usually more or less undulated by constrictions; disk with 5 subequal, 

narrow, ridge-like ribs, separated by wide interspaces, In each of which are from 

2 to 5 subequal, prominent, squarish riblets; whole surface ornamented by a 

superimposed tessellation, which is usually worn off in the adult shells; ears 

similar to those of the right valve, there being nearly as pronounced a byssal 

notch in the anterior ear of the left valve as in the anterior one of the right. 
122 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

IJimens£on8.-Alt. 64 mm.; long. 53 mm.; hinge line 19 mm. ·; diameter, 

right valve 10 mm.; left valve 13 mm. 

This variety is similar to the typical P. wattsi, except that it is somewhat less 

convex and less constricted, and, as a consequence, has no prominent nodes on the 

ribs of the left valve. Both the typicalP. wattsi and its variety morani are allied to 

P. h,amlini, but are much taller and have relatively much shorter ears and narrower 

ribs. The degree of. convexity is approximately the same in P. hamlin1~ and P. 

wattsi var. morani. 

P. wattsi var. nwrani is known so far only from beds exposed on Mr. T. H. 

Moran's place, Priest Valley, Monterey County, where it is associated with Area 

(cf) trilineata Conrad, Ostrea (cf) lurida Carpenter, Echinarachnius (cf) expent1·icus Eschscholtz, and Sc-utella fairbanksi Merriam?. This fauna probably indicates a lower ·Pliocene horizon. 

The type is an almost perfect left valve (U. S .. N. M. No. 164929) and, together ; 

with the other figured specimens, comes from ~Ir. lVIoran's place in Priest Valley, 

Monterey County. · · 

RANGE. 

Pliocene (lower). T. H. Moran's · place, SW. i sec. 14, T. 20 S., R. 12 E., Mount 

Diablo meridian, · Priest Valley, Monterey County (Hamlin and Arnold). 

PECTEN (LYROPECTEN) ASHLEYI n. sp. 

Pl. XLVII, figs. 1 and 1a; Pl. XLVIII, fig. 1 

1895. Pecten estrellanus Ashley (not of Conrad, 1857), Proc. Cal. Acad. Sci., ser~ 2, vol. 5, 1895, p. 338. 

IJescrption.-Adult shell averaging about 150 millimeters in altitude, much 

longer than high, subequivalve, convex, inequilateral, the posterior portion of the 

disk being obliquely produced; sides concave above. Right valve with about 18 or 

19 prominent, rather squarish, flat-topped (convex-topped near umbo) ribs which 

are more or less prominently sculptured by numerous thread-like, somewhat imbricated, radial ridges; jnterspaces narrower than ribs, channeled and ornamented by 

an intercalary riblet and, in the later stages of growth, by several .imbricated radial 

lines; hinge line ahout.one-half length of disk; anterior ear somewhat produced, 

prominently notched and sculptured by numerous imbricating incremental lines 

and several inore or less prominent unequal radials; posterior ear slightly shorter 

than anterior, and similarly sculptured except with more, but less conspicuous, 

radials. Left valve slightly more convex than right and · similar to it except that 

the ribs are slightly narrower and more convex, and the interspaces are correspondingly wider and generally have the bottom entirely sculptured with subequal 

radial lines, with the prominent intercalary lacking; ears subequal, rectangularly 

truncated and sculptured . .in a similar manner to the posterior ear of the right 

valve. 

Dimensions.-;-Alt. 152 mm.; long. 175 mm.; hinge line 85 mm.; diameter 

65 mm.; apical angle 110°. 

This magnificent species is characterized and is distinguishable from allied 

forins by its great relative length and numerous ribs (P. crassicard@, a nearly 
PLIOCENE PECTENS. 123 

allied form, having only 16 or 17). IJ. ashleyi is distinguishq,ble from P. cen·osensis, with which it is general1y associated, by the smaller number of ribs and the 

longitudinal sculpture of the same. 

In the Third street tunnel, Los Angeles, P. asldeyi is associated with the 

following fauna: Pecten opuntia, P. latiauritus, P. pedroanus, P. stearnsii, 

Glyph is densiclathrata, Nassa n. sp. ~, Macorna sp. indet., Area multicostata, 

Lim,a hamlini, Buccinurn sp. indet., Neve-rita recluziana, Astarte sp., Priene 

oregonensis, Ostrea veatchii, Pleurotoma sp. indet., carditoid, coral, bird bone, 

crab's claw. This association of species indicates a horizon of the lower Pliocene. 

A fragment of a large specimen of P. ashley?~ was found by Doctors Dall 

and Stearns in the low hills across the mesa three-fourths of a mile northeast of 

Pacific Beach, near San Diego. 

P. a.shleyi is also found in the Pliocene at Cerros Island and San Fernando. 

The type is from Cerros Island, and is now in the collection of the U niv,ersity 

of California. Named in honor of Dr. G. H. Ashley, of the United States 

Geological Survey, whose pioneer work in the Santa Cruz Mountains added' 

greatly to the knowledge of the \Vest Coast Tertiary. 

RANGE. 

Pliocene. Uerros Island, off Lower California (Univ. of Cal.): Temescal Canyon, 

Santa Monica Mountains, Los Angeles County (Rivers); Third street tunnel, 

Los Angeles (Hamlin); near Pacific Beach, San Diego (Dall, Stearns); San 

Fernando, Los Angeles County (Ashley); Cosmalia, Santa Barbara County 

(F. M. Anderson); Olinda, Puente Hills, Orange County (Eldridge). 

PECTEK (PLAGIOCTENIUM) CERROSENSIS Gabb. 

Pl. XLIV, fig. 5; Pl. XLIX, figs. 1, la, and lb. 

1869. Pecten cerrosensis Gabb, Pal. Cal. , vol. 2, 1869, p. 32, pl. 9, figs. 55, 55a. 

1898. Pecten cerrosensis Gabb, Dall, Trans. w ·agner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 705. 

1898. Pecten ( Plagioctenium) subventricos~ts Dall, Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 707, 

pl. 29, fig. 8. 

1903. Pecten (Plagioctenium) subventricosus Dall, Arnold, Mem. Cal. Acad. Sci. , vol. 3, 1903, p. 

1904. Pecten s~tbventricosus Dall, Rivers, Bull. So. Calif. Acad. Sci., vol. 3, no. 5, p. 69. 

1904. ?Pecten ventricosus Sowerby, Rivers, op. cit., p. 69. 

114. 

Description.-Adult shell averaging about 100 millimeters in altitude, somewhat 

longer than high, subequivalve, biconvex, inequilateral, being somewhat obliquely 

produced posteriorly; margins more or less sharply serrate; sides nearly straight 

and sloping at a rather steep angle. Right valve slightly less convex than left, 

with 21 to 23 prominent rounded, smooth-topped ribs, which in the adult broaden 

and become ornamented above with looped incremental lines near the periphery 

of the disk; interspaces considerably narrower than the ribs, with. sloping sides 

and :flat, narrow bottoms, which are ornamented by a dense fringe of fine, sharp 

concentric lamellre; hinge line a little more than one-half as long as disk; anterior 

ear slightly longer than posterior, and ornamented . by ridges and numerous 

imbricating concentric lines; byssal notch of medium size; posterior ear nearly• 
124 I 

TERTIARY .AND QUATERNARY PECTENS OT!' CALIFORNIA. 

rectangularly truncated, and ornamented . by more or less prominent radiating 

ridges and · numerous fin.e incremental lines. Left valve similar to the right, 

except that the ribs are slightly narrower and the interspaces wider; anterior ear 

showing a shallow concave margin near disk, otherwise ears similar to those of 

the right valve. Hinge similar to that of I>. circularis V9T. cequisulcatus. 

Dim.ensions.- Alt. 105 mm.; long. 112 mm.; . hinge line 56 mm.; diameter 

35 mm. 

This species is close to P. var. cequisulcatus, but may be distinguished from 

that species by its larger size when adult, less ventricose valves, more and rounder 

ribs, and shorter hinge line. The San Fernando forms have slightly squarer ribs 

and, so far as known, do not reach the enormom; size (the type being over 200 

millimeters in altitude) attained by the specimens from the type locality; otherwise 

they are identical. One Ventura County specimen has an altitude of over 100 

millimeters. 

A variety of this species (No. 14644 C. S. M. B.) from Brown's Canyon, 

near Santa Monica, Los Angeles County, has a somewhat wider umbonal angle 

(105°) and a slightly obliquely truncated posterior ear on the right valve; otherwise 

the specimen is .typical. 

P. cerrostn.'$i8 is confined to the Pliocene, but no doubt ranges through nearly 

the whole of this epoch. The forms in the San Fernando beds show· a closer 

affinity to P. var. cequisulcatus, of . which they may be the precursors. 

RANGE. 

Pliocene. Station 3, 1 mile north of Camulos, Ventura County (Watts); San Fernando tunnel, Los Angeles County (Ashley, Watts, Arnold); Temescal Canyon, . 

Santa Monica Mountains, Los Angeles County (Rivers); Browns Canyon, Santa 

Monica, Los Angeles County (Watts); Pacific Beach, well at Twenty-second and 

H streets, San Diego, and Cholas Valley, San Diego County (Stearns); Pacific 

Beaeh (Hemphill, Arnold); Cerros Island, off Lower California (Veatch and 

others); Turtle Bay, Lower California (Hemphill). 

PECTEN (PLAGIOCTENru:M) ·COOPER! n. sp. 

Pl. XLIX, :figs. 2, 3, and 4. 

Desm•iption.-Shell averaging about 30 millimeters in altitude, slightly longer 

than high, bot_h valve::; moderately convex, disks ::;lightly obliquely produced 

posteriorly, moderately thick; disk generally characterized by several more or 

less prominent concentric zones of interrupted growth, which show as color bands 

even on the fossil shells; sides nearly straight; margins serrate. Right valve 

with 18 to ·20 flat-topped, squarish ribs, which tend to flatten. out and become 

more convex topped in the later stages of growth; interspaces narrower than 

the Tibs, and ~rossed on the bottom by numerous, fine, sharp, incremental lirulre, 

which become obsolete on tbe ribs excepting in the later ::;tages of growth; 

hinge line somewhat more than · one-half length of. disk; anterior ear slightly 

.produced and ornamented by 4 or 5 prominent radials and numerous incremental 

.lines; byssal notch deep and sharply defined; posterior ear slightly obliquely trun-

, 
PLIOCENE PECTENS. 125 

cated, and sculptured· by obsolete radials and fine incremental lines. Left valve 

similar to right, except that the rib8 are narrower and the interspaees correspondingly broader. 

D/Jnensions.-Alt. 30 mm.; long. 31 mm.; hinge line 17 mm.; diameter 12 

mm.; umbonal angle 95°. 

This species is characterized by the number of its ribs and the concentric 

imbricating bands of interrupted growth. It is distingp.ishable frori1 P. cerrosensis 

by its fewer ribs, less prominent lirulre on the sides of the ribs, and its 

prominent concentric bands of interrupted growth; distinguishable from P. 

cirmtlar·i8 and varieties by its less ventricosity, fewer ribs, and its characteristic 

concentric sculpture. Specimens of this species were noticed in a box in the 

National Museum with P. sttbventricosus [ =P. cerrosensis] from Pacific Beach, San 

Diego. 

P. cooperi is so far known only from the Pliocene of Pacific Beach, near 

San Diego. Type and cotype now in the collection of Delos Arnold. Named in 

honor of the late Dr. .J. G. Cooper, one of the pioneer paleontologists of the 

Pacific Coast. RANGE. 

Pliocene. Pacific Beach, San Diego (Hemphill, Arnold). 

PEcTEN (PLAGIOCTENruM) crRcuLARrs Sowerby. 

Pl. XLII, figs. 3, 4, 5, and 6; Pl. XLIV, figs. 6, 6a, 6b, and 7. 

1835. Pecten tumidus Sowerby, Proc. Zool. Soc. Lond., 1835, p. 109; not Pecten tumidus Turton, 1822, 

nor eiten, 1830. 

1835. Pecten ·rcularis Sowerby, Proc. Zool. Soc. Lond., 1835, p. 110. 

1843. entricosus Sowerby, Thes. Conch., vol. 1, pt. 1, Pecten, p. 51, pl. 12, figs. 18, 19, and 26; 

tumidus Sowerby, 1835. 

1843. Pecten ircularis Sowerby, Thes. Conch., vol. 1, pt. 1, Pecten, p. 51, No. 18, pl. 12, fig. 23. 

1852. Pecten entricosus Sowerby, Reeve, Conch. Icon., vol. 8, Pecten, sp. 31, Nov., 1852, pl. 7, figs. 

31 a and b. 

1853. Pecten ircularis Sowerby, Reeve, Conch. Icon., vol. 8, June, 18.53, Pecten, sp. 137, pl. 31, fig. 137. 

1869. Pecten entricosus Sowerby, Gabb, Pal. Cal., vol. 2, p. 104 ( = P. var. ::equisulcctlus Carpenter, in 

part . 

1888. Pecten ·entr'icosus Sowerby, Kuster and Kobelt, Conch.-Cab., vol. 17, pt. 2, sp. 64, p. 100, taf. 28, 

figs. 1-3. 

1888. Pecten Dentipecten) circvlaris Sowerby, Kl.ister and Kobelt, Conch.-Cab., vol. 17, pt. 2, sp. 151, 

p. 1 8, taf. 51, figs. 5- 8. 

1888. Pecten ;entricosus Sowerby, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 258. 

1898. Pecten ( Plagioctenium) ventricosus Sower by, Dall, Trans. ·wagner Free In st. Sci., vol. 3, pt. 4, 

1898 p. 710 . . [+ P. inca Orb., 1847; ?=P.pomatiaVal., Voy. Venus, 1835, pl.19,fig. 3 (fide 

Dall 1898. ) ] 

1898. Pecten Pecten) compactus Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 707, pl. 34, 

fig. (right valve of a young specimen). 

1903. Pecten (Plagioctenium) ventricosus Sowerby, Arnold, Mem. CaL Acad. Sci., vol. 3, 1903, p. 114, 

pl. 1 , figs. 3, 3a, 6, and 6a ( =P. var. ;;equisulcatus Carpent.er, 1863, in part). 

1904. Pecten entricosu.s Sowerby, Keep, w·est Am. Shells, pp. 41-42. 

D escri tion.-Shell averaging about 46 millimeters in altitude, about as long 

as high, s bequivalve, very convex, inequilat.eral, the posterior portion of the disk 
126 TERTIARY .AND QUATERNARY PECTENS OF CALIFORNIA. 

being somewhat obliquely produced; margins sharply serrate; sides quite concave 

above. Right valve with 19 to 21 squarish, close-set, smooth ribs, which, in the 

adult, flatten out and have sloping sides. near the periphery of the disk; interspaces 

very narrow and channeled; whole surface of disk sculptured by obsolete, wavy 

lines of growth; hinge line about two-thirds len·gth of disk; eartl equal in length, 

separated from disk by a prominent groove posteriorly and small ridge anteriorly; 

anterior ear with 4 rather faint I:adials, and numerous fine, imbricating incremental 

lines; byssal notch deep, its upper side being about parallel with the · hinge line; 

posterior ear with delicately curved extremity, and ornamented by fine incremental 

lines, and also on the lower half by faint nidials. Left valve darker colored than 

right, and with ~he ribs narrower, flat-topped, and having sloping sides; interspaces 

wider, and covered both on the bottom and sides by fine, sharp, concentric lamellre; 

ears as in the right valve, except that the anterior one is not so conspicuously 

notched. Hinge strong, the pair of cardinal ·crura in the right valve being exceedingly well developed. Color patterns from light to dark brownish red. 

Dimensions.-Alt. 46 mm.; long. 47 mm.; hinge line 32 mm.; diameter 33 mm. 

This typical form is characterized by its great and regular convexity, broad 

ribs, and strong hinge. Type from Gulf of California. 

Found living from the Gulf of California southward to Panama; in the Pleistocene farther north. Erroneously reported from the Philippines by Sower by. 

RANGE. 

Living. Gulf of California to Panama · (Sower by, Carpenter, Button); St. Elena, 

off western coast of Colombia, South America (Sowerby.). · 

Pleistocene. San Pedro; San Diego; Lower California (Hemphill, Stearns, Orcutt); 

Ventura; San Pedro~ San Di~go (Arnold); Springdlle, Ventura County 

(Bowers). 

Pliocene ( n. Cholas Valley, near San Diego (Stearns). 

PECTEN (PROPEAMUSIUM) RIVERS! n. sp. 

Pl. XLIV, figs. 8 and 9. 

Desm·iption.-Shell averaging about 14 millimeters in altitude, about as long 

as high, circular in outline, equilateral, compressed, white, translucent; margins 

smooth. Right valve much compressed; surface smooth except for numerous 

very fine, regular, imbricating lamellre; hinge line one-half length of disk; ears 

distinctly separated from disk by impressed line, subequal in length; the anterior 

arcuate in front and with about 12 subequal prominent radials and numerous 

fine, regular, imbricating, incremental lamellre; the posterior slightly obliquely 

truncated and sculptured similarly to the anterior, except that the radials are 

nearly obsolete; byssal notch of medium prominence. Interior of disk smooth 

until an altitude of 15 millimeters is reached, when about 20 to 22 small, rounded, 

radiating ribs appear and continue to the periphery. Left valve somewhat more 

convex than the right, and ornamented externally by numerous unequal, 

prominently imbricated ribs, the alternate ones being intercalated between 

sl~ghtly larger ones; whole surface sculptured by fine imbricating lamellre; 
PLEISTOCENE PEC'l'ENS. 127 

anterior e r similar to that of the right valve, except that it is more strongly 

radially ri bed and is less sinuated; posterior ear similar to that of right valve, 

except tha it is more strongly ribbed. Interior of left valve similar to that of 

the right, and having the radial ribs developed only after attaining an altitude 

of about 1 millimeters. 

Dimm sions.-Alt. 1'7 mm.; long. 18 mm~; hinge line 9 mm.; diameter 3.5 mm. 

This s ecies is very closely allied to P. alaskensis, of which it is undoubtedly 

the precur or. It differs from the latter in having the external ribs on the left 

valve mor prominently imbricated above, and in having the internal ribs of both 

valves app ,aring only after an altitude 'of about 15 millill!eters has been attained. 

The . r lations existing between P. riversi and P. alaskensis are a good 

illustration of Hyatt's law of acceleration of development. a In the former, the 

Pliocene p ecursor of the latter, the internal riblets are developed only in the 

adults or fter an altitude of about 15 millimeters is reached. In P. alaskensis, 

the living pecies, this characteristic has been pushed backward in the process of 

developme t to or nearly to the embryonic stage, continuing, however, in the 

later stage of growth, and appearing as a well-developed internal riblet from 

near the u 1bo to the periphery. 

P. riv rsi is known at present from only two localities, the Pliocene of Santa 

lVlonica Ca yon and the Pleistocene (lower San Pedro formation) of Deadman Island, 

near San Pedro. The species is named in honor of Dr. J. J. Rivers, of 

Oceanpark, whose work in the fossiliferous deposits of Santa Monica and vicinity 

lias throw much light on the distribution of the later Tertiary and Pleistocene 

formations. 

The t pe, which is now in the collection of Delos Arnold, is from the 

Pliocene o Santa Monica Canyon, Los Angeles County, and was collected by 

Doctor Riv 

RANGE. 

Pleistocene (lower San Pedro formation), Deadman Island, near San Pedro (Arnold). 

Pliocene. anta Monica Canyon, Los Angeles County (Rivers). 

PLEISTOCE.NE PECTENS. 

[ Those known first to appear in the Pleistocene formations.] 

PECTEN (PEcTEN) DIEGENSIS Dall. 

Pl. LI, figs. 1, la, and lb. 

1844. Pecten oridtts Hinds, Zool. Voy. Sulph., 1844, p. 60, pl. 17, fig. 6; not Ostrea=(Pecten) florida 

Gme in, 1792 (fide Dall). 

1852. Pecten oridus Hinds, Reeve, Conch. Icon., vol. 8, 1852, pl. 8, fig. and sp. 34. 

1888. Pecten Vola) fioridus Hinds, Kuster and Kobelt, Conch.-Cab., voL 17, pt. 2, Spondylus und 

Pect n, sp. 173, taf. 57, fig. 2. 

a " All mo ifications and variations in progressive series tend to appear first in the adolescent or adult stages of 

growth, ana the 1 to be inherited at earlier and earlier stages, according to the laws of acceleration, until they either 

become embryo ic or are crowded out of the organization and replaced in the development by characters of later 

origin" .-A. Hy tt, in " Genesis of the Arietidoo," preface, p. ix. 
12H TERTIARY AND QUATERNARY PECTENS OF CALIJ!'ORNIA. 

1888. Janira florida Hinds, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 244 (P. hemphilli and 

P. stearnsii in part). 

1898. Pecten (Pecten) d'iegensis Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 710. 

1903. Pecten diegeniis Dall, Arnold, Mem. Cal. Acad. Sci, vol. 3, 1903, p. 106, pl. 12, fig. 5. 

1904. Pecten diegcensis Dall, Keep, \Vest. Am. shells, p. 39. 

Description.-Shell averaging about 60 miilimeters in altitude, longer than 

high, inequivalve, plano-convex, m·· nearly so, equilateral and with smooth margins; 

base evenly rounded; sides slightly concave al;>Ove. Right valve somewhat convex 

(more pronounced near the umbo), and ornamented by about 22 or 23 prominent T-railshaped ribs, flattened, and generally longitud,inally ridged or sulcated o.n top, which 

overhang deep, narrow; flat-bottomed inte'fspaces; whole surface sculptured by 

numerous fine, sharp, incremental Jines; hinge line slightly less than one-half length 

of disk; ears equal, slightly convex, rectangularly truncated, sculptured by fine, 

sharp. incremental lines; anterior ear with small .byssal notch. Left valve flat or 

nearly so, generally concave near apex, ornamented by 21 or 22 prominent, narrow, 

convex-topped ribs, which are separated by concave-bottomed · interspaces about 

equal in width to the ribs; whole surface prominently sculptured by numerous · 

regular, fine, sharp, concentric, r~ised lines; ears concave, convexly truncated, and 

ornamented by the same concentric ~culpture as the disk. Color, red and reddish 

brown, the left valve always being much darker than the right. 

Dirnensions.-Alt. 58 mm.; long. 64 mm.; hinge line 29 mm.; diameter 13 mm.; 

umbonal angle (left valve) 95°. . · 

This ~pecies iH distinguishable from its nearest relative, and probable precursor; 

P. stearnsii, by the smaller number and greater height of its (P; d1~egensis) ribs, a~d 

relatively somewhat longer hinge line. The ribs of P. diegensis have sometimes 

as many as three longitudinal sulci. Mrs. Oldroyd has two specimens taken from 

fishermen's nets at San Pedro, which measure over 150 millimeters (6 inches) in 

length, and are exceptionally high colored for this species. 

RANGE. 

Living. Monterey (Button; Mrs. &Lambert and others); San Pedro (Oldroyd; Raymond); Catalina Island, 10 fathoms (ArnGld); San Diego (Raymond). (In all 

cases dredged.) · 

Pleistocene. San Diego (Hemphill). 

PECTEN (N ODIPECTEN) SUBNODOSUS Sower by. 

Pl. LII, fig. 1; Pl. LIII, figs. 1 and lei. 

1835. Pecten subnodosus Sowerby, Proc. Zool. Soc., 1835, p. 109. 

1842. Pecten subnodosus Sowerby, Thes. Conch., vol. 1, pt. 1, 1842, p. 112, pl. 15, fig. 97. 

1852. Pecten subrwdosus Sowerby, Reeve, Conch. Icon., vol. 8, Monog. Genus Pecten, Nov., 1852, pL 4, 

fig. and sp. 20. 

1867. Pecten 'Intermedius Conrad, Am. Jour. Conch., vol. 3, 1867, p. 7 (fide Dall, 1898}. 

1888. Pecten subnodosus Sowerby, Kuster and Kobelt, Conch.-Cab., vol. 17, pt. 2; Sponcil.ylus und Pecten, 

no. 71, p. 112, taf. 32, fig. 3. 

1897. Lyropecten subnodosus Sower by, Verrill, Trans. Conn. A cad. Sci., vol. 10, p. 64. 

1898. Pecten ( Nodipecten) subnodosus Sower by, Dall, Trans. Wagner Free In st. Sci., vol. 3, pt. 4, 1898, 

p. 710. 
PLEISTOCENE PECTENS. 129 

Descrption.-Shell averaging about 110 millimeters in altitude, slightly broader 

than high, subequivalve, subequilateral, of medium thickness, :;omewhat ventricose, 

and with margins finely serrate; base regularly rounded; sides sloping and nearly 

straight. Right valve slightly less ventricose than left, with about 9 or 10 broad, 

flat, subequal ribs; interspaces subequal, with slightly rounded bottoms; whole 

surface sculptured by numerous (averaging about 7 on each large rib) radiating 

ribl~ts, whose surfaces and interspaces are crossed by numerous fine, wavy lirulre 

of growth; several faint undulations are also generally noticeable on the disk; 

· hinge line slightly longer than one-half length of disk; anterior ear about one and 

three-eighths times the length of the posterior, arcuate in front, and ornamented 

by several prominent radiating riblets and fine, sharp, incremental lines; byssal 

notch not very prominent; posterior ear rectangularly truncated and sculptured 

.similarly to anterior. Left valve re.sembling the right except that it is slightly 

more ventricose and the ribs are ornamented by more or less elevated, hollow 

nodes, those on the alternating ribs being the more prominent. 

Dimensions.-Alt. 112 mm.; long. 120 mm. ~ hinge line 66 mm.; diameter 

45 mm. 

Doctor Dall is of the opinion that there is little reason for separating this 

form from the P. nodosus of the Antilles, although he says the latter is generally 

thinner, and bas the nodosity more pronounced. 

A fragment of a left valve of a variety of P. subnodosus from the upper 

San Pedro formation (Pleistocene) of Deadman Island, San Pedro, has 17 ribs whose 

sides are concavely excavated, thus giving them a somewhat T -shaped cross section. 

The middle rib and the fourth rib on each side of it are very prominent, while 

the other ribs are much smaller. Sculpture as in typical P. subnodosus. , 

The specimen figured is a living shell from the western coast of Mexico, and 

is now in the collection of the department of geology, Leland Stanford Junior 

University. · 

RANGE. 

Living. Coast of Lower California to Ecuador and the tropical shores of South 

America (Carpenter). 

Pleistocene. San Pedro (A. A. Wright; Arnold); Cerros Island and other points on 

the coast of Lower California (Dall) . 

.Pliocene. Temescal Canyon, Santa Monica Mountains, Los Angeles County (Rivers). 

PECTEN (CHLAMYS) LATIAURITUS Conrad var. CERRITENSIS n. var. 

Pl. XL VI, figs. 6 and 7. 

1903. Pecten ( Chlamys) latiaurit~s Conrad var. jragilis Arnold, Mem. Cal. Acad. Sci., vol. 3, pt. 2, 1903, 

p. 112, pl. 12, fig. 8; not Pecten fragilis Jeffreys, Ann. and Mag. Nat. Hist., 4th ser., vol. 18, 

1876, p. 424. 

Description.-Shell of same general type as P. latiaurit?.ts. More compressed 

and much thinner; ribs seven to nine, very low and rounded, with shallow, rounded 

interspaces; surface smooth, the concentric sculpture being nearly obsolete; hinge 

long; ears rather sharply pointed. 

17260-No. 47-06-9 
J30 TER'riARY AND QUATERNARY PECTENS OF CALIFORNIA. 

Dimensions.-Alt. 26 mm.; long. 26 mm.; hinge line 25 mm.; diameter 7.8 mm. 

This variety is distinguishable f~·om Dall's variety fucicolrtts, which it resembles, 

by having a longer hinge line and generally more pointed ears. 

Found associated with the typical species in the Pleistocene '( upper San Pedro 

formation) at· San Pedro and San Diego. 

RANGE. 

Pleistocene. San Pedro; San Diego (Arnold). 

PECTEN (CHLAMYS) LATIAURITUS Conrad var. DELOSI n. var. 

Pl. XLVI, figs. 9, 9a, 10, and lOa. 

Descr1jJtion.-Shell averaging about 12 millimeters in altitude, slightly longer 

than high, subequivalve, both valves only slightly convex, inequilateral, the disk 

being decidedly oblique to the hinge lipe and somewhat produced posteriorly; sides 

nearly straight; margins rough. Right valve with about 16 prominent smoothtopped squarish ribs; interspaces wider than the ribs, flat-bottomed and ornamented 

on the bottom and sides by numerous prominent, regular, equidistant, imbricating, 

incremental lamellre; hinge line as long as, ·or slightly longer than, the disk; ears 

about equal in length; anterior ear long· and narrow, separated from the disk by a 

deep, sharply defined, byssal notch and sculptured by five or six prominent radials 

and numerous, regular, imbricating, incremental lamellre. .Left valve similar to 

right except that the ribs are slightly narrower and the incremental lamellre extend 

over the tops of the ribs in some specimens; ears acutely pointed and sculptured by 

numerous regular, sharp lamellre; anterior somewhat shorter than the posterior and 

with four major and as· many intercalary radials; posterior with four or five radials. 

Dimensions.--Alt. 12 mm.; long. 12.5 mrn.; hinge line 13.5 _rum.; diameter 3.5 

mm.; umbonal angle 98°. 

This beautiful little Pecten, one of the smallest . found in our fauna, is characterized by its extremely long hinge line and prominently lamellated surface. It is 

distinguishable from the typical P. latZ:auritus and varieties, with which it is allied, 

by its longer hinge line and prominently lamellated interspaces. 

The living specimens have the ribs more prominently lamellated above than the 

fossil .forms. .P. var. delosi appears to occupy somewhat deeper (and consequently 

colder) water than the typical form. The specimens of P. latiauritus found in the 

Santa Barbara and Monterey reg·ions appear to lean strongly toward this variety. 

P. delosi has beeri found fossil so far only in the lower San Pedro formation 

(Pleistocene) at Deadman Island, near San Pedro. Types now in the collection of 

Delos Arnold, the writer's father, after whom the species is named. Living specimens dredged in 15 fathoms at Catalina Island. 

RANGE. 

Living. Santa Catalina Island, Los Angeles County, in 15 .fathoms (Arnold); Santa 

Barbara (Dall); Monterey (Button). 

Pleistocene (lower San Pedro formation). Deadman Island, San Pedro (Arnold). 
PLEISTOCENE PECTENS. 131 

PECTEN (CHLAMYS) LATIAURITUS Conrad var. FUCICOLUS Dall. 

Pl. XLVI, figs. 8 and Sa. 

1898. Pecten latiauritus var. jucicolus Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 710. 

Description. -Shell of same general type as P. lat£auritus. Moderately compressed~ smooth, concentric sculpture obsolete; ribs low~ rounded, wide, entire; 

hinge line shorter than in the type, and without any sinus between the posterior 

ear and the disk. 

Dimeusions.-Alt. 30 mm.; long. 31 mm. 

"'This form lives attached by the byssus to the giant kelp of the Californian 

coast, and the absence of shock, due to the floating situs, is probably correlated 

with the obsolescence of the ribs and the posterior sinus. lntergradations with 

the type are not at all rare." (Dall, 1898.) 

RANGE. 

Living. Santa Barbara, south to Cape St. Lucas (Dall). 

Pleistocene. San Pedro; San Diego (Dall; Arnold). 

PECTEN (CHLAMYS) LATIAURITUS Conrad var. MONOTIMERIS Conrad. 

Pl. XL VI, figs. 4; 5, and 5a. 

1837. Pecten monotimeris Conrad, Jour. Acad. Nat. Sci. Phila., vol. 7, 1837, p. 233, pl. 18, fig. 10. 

1863. Pecten monotimeris Conrad, Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1888. Pecten monotimeris Conrad, Kuster and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondylus und Pecten, 

No. 257, p. 276, taf. 72, figs. 7 and 8. 

1888. Pecten latiauritus Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 257 (in part). 

1892. Pecten monotimeris Conrad, Keep, West Coast Shells, 1892, p. 167, fig. 140. 

1897. Pecten (Leptopecten) monotimeris Conrad, Verrill, Trans. Conn. Acad. Sci., vol. 10, p. 69. 

1898. Pecten latiauritus var. monotimeris Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, 

p. 709. 

1903. Pecten ( Chlamys) latiaurittts Con. var. monotimeris Conrad, Arnold, Mem. Cal. Acad. Sci., vol. 3, 

pt. 2, 1903, p. 112, pl. 12, figs. 4 and 4a. 

1904. Pecten latiauritus var. monotimeris Conrad, Keep, West Am. Shells, p. 40, fig. 20. 

Description.-Shell of the general type of P. latiattritus, but more oblique, 

inflated, and markedly shorter, with smaller ears; ribs generally prominent and 

squarish, and interspaces deeply channeled; incremental sculpture sometimes very 

pronounced. 

Dimensions.-Alt. 20 mm.; long. 19 mm.; hinge line 16 mm.; diameter 9 mm. 

This variety is characterized by its ventricosity, well-defined ribs, and relatively short disk and hinge line. P. var. nwnotimeris is very common at Los 

Cerritos Hill, near San Pedro, but is much rarer in the other Pleistocene localities than the typical 1~. latiaurit11s. 

Found in the fossil state in the upper San Pedro formation (Pleistocene); also 

occurs recent. RANGE. 

Living. Fort Point, San Fraiwisco (Button); Santa Barbara to San Diego (Dall). 

Pleistocene. Santa Barbara; San Pedro (Dall); San Pedro; San Diego; Ventura 

(Arnold); Newport, Orange County (No. 11895, C. S. M. B.) (Watts). 
132 TERTIARY AND QUATERNARY PECTENS OF C.A:LIFORNIA~ 

PECTEN (PLAGIOCTENIUM) CIRCULARIS Sowerby var. lEQUISULCATUS Carpenter. 

Pl. L, figs. 1, 1a., and 1b,· also text fig. 1, p. 45; fig. 2, p. 46. 

1863. Pecten [-ventricosus var.?] cequisulcatus Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1865. Pecten (?var.) cequisulcatus Carpenter, Ann. and Mag. Nat. Hist., 3d ser., vol. 15, 1865, p. 179. 

1869. Pecten ventricosu,c;; Gabb, Pal. Cal., vol. 2, 1869, p. 104 .. 

1888. Pecten cequisulcatus Carpenter, Kuster and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondylus und 

Pecten, no. 249, p. 269, taf. 71, figs. 1 and 2. 

1888. Pecten ventricosus Cooper, Seventh Ann. Rept. Cal. St. Min., 1888, p. 258 (Quaternary record 

only). 

1892. Pecten cequisulcatus Carpenter, Keep, West Coast Shells, 1892, p. 166, fig. 139. 

1893. Pecten cequi.c;;ulcatus Carpenter, Williamson, Proc. U. S. Nat. Mus., vol. 15, for 1892, p. 193. 

1898. Pecten ( ventricosus var.?) cequisulcatus Carpenter, Dall, Trans. Wagner Free In st. Sci., vol. 3, pt. ~ 

4, 1898, p. 711. 

1898. Pecten ( Plagioctenium) ventricosus Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 710 

(in part). 

1902. Pecten cequisulcatus Carpenter, Williamson, Bull. So. Cal. Acad. Sci., vol. 1, No. 5, May, 1902, 

pp. 51-64, pls. 4-6. 

1903. Pecten (Plagioctenium) 'Ventricosus Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 114, pl. 11, figs. 

3, 3a. 

1903. Pecten (Plagioctenium) neU'somi Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 113, pl. 11, figs. 1 

and 1a (a young shell) . 

1904. Pecten cequisulcatus Carpenter, Keep, West Am. Shells, p. 39, fig. 18. 

· Description.-Adult shell averaging about 75 millimeters in altitude, much 

longer than high, the anterior portion of the disk being obliquely produced; sides 

somewhat concave above; shell rather thin; margins serrate. Right valve with 20 

to 22 moderately prominent, flat-topped ribs separated by much narrower, flatbottomed interspaces; lateral areas about as wide as two normal ribs; . whole surface 

{)f disk sculptured by fine. sharp, looped, incremental lines; hinge line about five-

·eighths length. of dtsk; ears equal in length; anterior ear sculptured with fine 

·concentric lines and 7 or 8 more or less prominent radials; byssal notch deep 

·and sharply defined; posterior ear rectangularly truncated, and sculptured by 

concentric lines and obsolete radials. Left valve with narrower ribs, which have 

more sloping sides, and more prominent lamellre of growtp in the interspaces; 

interspaces correspondingly broader; ears similar to those of right valve, except 

that the posterior is. not sharply notched. Color, white to light reddish yellow 

iblotehed with shades of reddish brown, the left valve being always perceptibly 

,darker colored than the right. 

Dtrnensions.-Alt. 72 mm.; long. 83 mm.; hinge line 51 mm.; diameter 36 mm.; 

umbonal angle 100°. 

This variety is more or less variable in regard to its convexity, obliquity, 

Telative width and he~ght o_f ribs, and coloration. In the young specimens the right 

valve is perceptibly more convex than the left; the ribH are relatively much squarer 

and more prominent, the interspaces correspondingly narrower and deeper, the 

hinge line comparatively longer, and the umbonal angle appears to be less, than 

in the adults. The tendency of the ribs to flatten out and the concentrir sculpture 

to become more irregular and rough as the shell grows older is evident to a greater 

or less degree in nearly all of the specimens e~amined. 
PLEISTOCEN~ PECTENS. 133 

The Pleistocene shells, as a rule, are more convex (the right valvA noticeably 

more so than the left), somewhat less oblique, and the ribs are slightly broader and 

more compact, than the living specimens. The young of P. var. mquistttlcatus have 

the characteristics of the Pleistocene form and are scarcely distingui~~able from the 

young· of P. cerrosensis. 

P. var. mquisulcatus varies from the typical P. circularis of the Gul£ of California and west Mexican coast fauna by its larger size when adult, flatter and thinner 

- disk, narrower ribs, and more subdued loration. These two forms seem to have 

separated during the Pleistocene, the living shells not appearing to give a satisfactory connection, while a large series of rleistocene specimens shows an obvious 

gradation. Doctor Dall (1898, p. 694), in speaking of the influence of environment 

npon the Pectens, thus mentions the reldtion between P. c£rcularis and P. var. 

mqulsulcatus: ""As in mammals and birds, tbe same species in the northern part of its 

[Pecten J rang·e is larger than in the south, ilinless it is a distinctively tropical species. 

But in color the rule is reversed, the soufthern specimens being lighter and · more 

brightly tinted than the northern ones in he same species. The specimens which 

live in deep water and swim actively a~·' usually thinner shelled and smoother, 

while those which inh~bit the lagoons are hjeavier, have more conspicuous concentric 

seulpture and more solid shells. These differences are very marked in our common 

east coast P. 1:rradians, of which P. dislocjtus Say is the southern lagoon form; and 

parallel difl'erences appear in the similarly rlblated P. ventrico8'U8 [ = P. circularis] and 

its variety ;:equisttlcatus on the Pacific coast * * *." 

P. var. mquis1tlcatus ranges from the Pleistocene to the Recent fauna. - I 

RANGE. 

Living. Santa Barbara to Pacific side of Jower California. 

Pleistocene. San Pedro; San Diego; Low, r California (Hemphill, Stearns, Orcutt); 

Ventura; San Pedro; San D.iego (A.rnoli); Springville, Ventura County (Bowers). 

PECTEN (PROPEAMUSIUM) ALASKENSIS Dall. 

Pl. LIII, :figs. 12, 2a, and 3. . 

1872. Pecten (Pseudamusium?) Alaskensis Dall, Am. Jour. Conch., vol. 7, 1872, p. 155, pl. 16, fig. 4. 

1886. Pecten (Propeamusium) alaskensis Dall, Bull. Mus. Comp. Zool., vol. 12, no. 6, 1886, p. 215, pl. 

5, figs. 7, 7a. ~ 1887. Not Pecten alaskensis W.hiteaves, Trans. Ro . Soc. Canada, vol. 4, sec. 4, 1887, p. 119 ( =P. 

vancou'Verensis Whiteaves, 1893 ). 

1888. Pecten alaskensis Dall, Kuster and Kobelt, C~nch.-Cab., vol. 17, pt. 2, Spondylus und · Pecten, 

sp. 220, p. 245, taf. 64, figs. 7, 8. 1 

1889. Pecten (Propeamusium) alaskensis Dall, Bull. Ul. S. Nat. Mus., No. 37, 1889, pl. 5, figs. 7, 7a. 

1893. Pecten Alaskensis Dall, Newcombe, Rept. on Mar. Sh. Brit. Columbia, Bull. Nat. Hist. Soc. 

Brit. Columbia, 1893, art. 5, p. 53. I . 

1895. Pecten (Pseudamusium) Alaskensis Dall, Taylor, Trans. Roy. Soc. Canada, 2d ser., vol. 1, 1895, 

sec. 4, p. 27. . 

1897. Arnusittm ( Propeamusium) Alaskensis Dall, Ve~rill, Trans. ,Conn. Acad. Sci., vol. 10, p. 65. 

1898. Pecten ( Propeamusium,) ala8kensis Dall, Trans. [V agner Free Inst. Sci., vol. 3, ~t. 4, 1.898, p. 711. 

The original description is as follows: 

Description;-"' Shell nearly equilateral, inequivalve, flesh color, with a blush of 

salmon color on the umbo of the superior Vialve. Internally white, the salmon color 
134 TERTIARY AND QUATERNARY PECTENS OF CALI.lfORNI.A. 

showing throligh the valve. Shell suborbicular, barring the auricles, which are wide 

and prominenf'' -Lower [or right] valve flattened, 0.1 inch (2. 5 millimeters) smaller 

than the upper one; sculpture of fine, close, equal, concentric ridges, sharply defined and 

separated by narrow non-canalicula.ted grooves. V :tlves covered with a fine velvety 

epi,dermis, ashy and very finely radiately striate. Surface of the valve, except for 

the ridges, smooth: Anterior auricle long, prominent, with a deep sinus. Posterior 

auricle small; both: ~ith strong elevated lines of growth, which rise into scales on 

the 8 or 9 fine ribs' with which the anterior auricle is furnished. Hinge )ine .straight, 

smooth. Inside of the valve polished, furnished with 21 rounded, .radiating ribs, with 

traces of others intercalated near the margin; nodulous or swollen at the more prominent ridges of growth and at the margin. · ·· _ · · 

"Upper [or left] valve similar, inside; anterior auricle shorter, not so deeply 

sinuated. Valve more convex than the under one, and a little Tar ger. Dorsal areas 

finely granulate. Umbo smooth; half way toward the· marg1q ~he strire· of increase 

become more conspicuous, and about 35 pseudoribs radiate toward the margin. 

These are formed by the elevation of the concentric lines of growth like ruffles,_ in 

such a way that the edge of one fluting of the ruffie overhangs the beginning of the 

next, and so on. These are very fragile, and when broken away show the nearly 

smooth surface of the valve underneath, without any true rib at all. Faint ribs are 

intercalated between the pseudoribs toward the margin." 

Dimensions.-Alt. 19.5 mm.; long. 1U.5 mm.; hinge line 9 mm.; diam. 5 mm.; 

umbonal angle 100°. _ 

This beautiful little deep-sea form is distinguishablR from the other small 

l)ectinidce of a like habitat by its internal lirre and the lack of radiating sculpture 

on the right valve. - Its nearest allied species in the Pacific coast waters is 

P. davidsoni, which, · so far as known, is confined to the deep watei·s west of 

certain parts of Alaska. 

P. alaskensis is found living, and is also preseryed in some of the Pleistocene 

deposits of Alaska and Vancouver Island. No record has as yet been made of 

it in the fossil state in any of the Pleistocene deposits of California. (See 

P. riversi, pp. 126-127.) 

RANGE. 

Living. Bering Sea to Panama Bay, usually in deep water (Dall). 

Pleistocene. Various points in Alaska (Dall); Point Holmes, Comox, Vancouver 

Island (vV. Harvey; C. F. Newcombe; Dall). 

RECENT PECTENS. 

[Those known only in the recent fauna of the west coast.] 

PECTEN (PECTEN) EXCA v ATUS Anton. 

Pl. XL VI, figs. 1, la, and lb. 

1835. Pecten dentatus C. B. Sowerby, Proc. Zool. Soc., 1835, p. 109; Thes. Conch., vol. 1, pt. 1, 

1842, p. 49, pl. 15, figs. 105-106; not Pecten dentatus J. Sowerby, Min. Conch. Gt. Brit., 

vol. 6, 1829, p. 143, tab. 574, fig. 1. 

1839. Pecten excavatus Anton, Verzeichniss der Conchylien, 1839,- p. 19, No. 710 (erroneously 

reported from China). 
RECENT PECTENS. 135 

1845. Pecten excavatus Anton, Philippi, Abbild. und Beschr. Conchyl., vol. 1, p~ 201, Pecten, pl. 2, 

fig. 1, 1845 (also erroneously reports this species from China). 

1846. Pecten excaratus Valenciennes,' Voy. Venus, 1846, pl. 19, fig. 1. 

1853. Vola dentata Sowerby, H. and A. Adams, Glen. Rec. Moll., vol. 2, 1853, p. 554. 

1863. Janira dentata Sowerby, Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1869. Janira dentata Sowerby, Gabb, Pal. Cal., vol. 2, 1869, p. 104. 

1888. Pecten (Vola) dentatus Sowerby, Kiister and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondylus 

und Pecten, sp. 112, p. 155, taf. 44, figs. 1 and 2. 

1888. Janira dentata Sowerby, Cooper Seventh Ann. Rept. Cal. St. Min., 1888, p. 244, (P. stearnsii 

in part). 

1897. Pecten dentatus Sowerby, Verrill, Trans. Conn. Acad. Sci., vol. 10, p. 57. 

Hl03. Pecten (Pecten) dentatus Sowerby, "Arnold, Mem. Cal. Acad. Sci., vol. 3, p. 104, pl. 12, figs. 

1 and 1a. 

Desc1·iption.-Shell averaging about 70 millimeters in altitude, slightly longP-r 

than high, inequivalve, plano-convex, eqrlilateral, and with more or less coarsely 

serrate margins; sides concave above. Right valve very convex, the disk near 

t~e apex projecting above the hinge line; ribs 22 or 23, evenly convex, much 

broader than high, and separated by interspaces which have only the importance 

of impressed lines; surface smooth except for incremental lines which loop down· 

ward on the tops of the ribs; hinge line greater than one-half length of disk; 

ears equal, convex, rectangularly truncated; anterior with two or three obsolete 

radiating ridges, and concentric sculptu!I'e; posterior generally · with concentric 

sculpture only. Left valve concave, ornamented by 22 or 23 prominent, rather 

narrow, squarish, flat-topped ribs, which are sometimes longitudinally faintly 

sulcated or ridged; interspaces slightly wider than ribs, fiat-bottomed, and each 

containing a prominent, rounded intercalary riblet; surface sculptured by numerous fine, sharp, regular concentric lines, which appear most prominent in the 

spaces between the ribs and riblets; ears equal, concave, laterally rectangular 

and sculptured by fine, sharp, incremental lines and two or three more or less 

prominent radiating ridges. Color salmon to salmon-pink, the left valve being 

the darker. 

Dirnensions.·-Alt. 65 mm.; hinge lil]le to ventral margin 59 mm.; long. 67 

mm.; hinge line 35 mm.; diameter 25 mm.; umbonal angle (left valve) 98°. 

This is the living representative of a genetic group which comprises P. 

keepi, P. vogdesi, and P. excavatus. Beginning with the oldest in the series, 

P. keepi, and advancing chronologically, the right valve becomes more convex, 

the lateral areas, which in P. keepi are very broad, become narrower, the ribs 

become more numerous, narrower, and higher, the interspaces correspondingly 

narrower, the hinge line relatively longer, and the ears more curved. 

P. excavat1t8 is of the same shape as the Japanese species P. laqueatus 

Sowerby, which has fewer, but squarer, broader ribs on the right valve. This 

last species has been reported from the Tertiary of Japan by Doctor Brauns in 

his Geology of the Environs· of Tokio. a '' P. laqueatus has been erroneously 

cited by Reeve from California" (Dall). 

Cooper mistook the flat valve of P. stearnsii for P. excavatus and labeled 

a specimen in the State Museum collection at the University of California, 

aMem. Univ. Tokio, No. 41 1881, p. 48, pl. 7, fig. 31. 
136 TER'riARY AND QUATERNARY PECTENS OF CALIFORNIA. 

Berkeley, '' Janira dentata Shy, San Pedro, Quaternary." The ·specimen 

undoubtedly came from the Pliocene of Deadman Island, instead of from the 

Quaternary. 

P. emcavatu~ is known only as living, and so far has been noted only from 

the Gulf of California, where it is a very common spe(.lies in some localities. 

RANGE. 

Living. Gulf of California (Sowerb~; Valenciennes; Carpenter; Button, and 

others). 

PEc'.rEN (CHLAMYS) HASTATUS Sowerby var. ALBIDUS Dall n. var. 

Pl. LII, ' figs. 2 and 2a. 

1904. Pecten ( Chlamys) hericius var. albidus Dall, MS. 

: Description.-Shell of the same shape and general appearance as P. vat. 

herici~ts, but. smaller when adult, being only about 45 millimeters in altitude. The 

sculpture on the right valve consists of numerous elevated, narrow, thread-like, 

imbricated riblets, which have. the appearance of be~ng grouped together in three or 

more unequal, equidistant, more or less convex fasciculi; the interspaces between , 

the fasciculi are ornamented by rib lets of equal prominence to those forming the -

fasciculi; anterior ear with about seven equal, prominently imbricated radials; 

posterior ear short ~nd with radial and imbricating sculpture; byssal notch quite 

prominent. Left valve similar to right, but with the fasciculi corresponding to the 

interspaces of the right valve, and consequently much narrower than tl}.e fasciculi 

of that valve. Color, white to very light pink. 

: Dimensions.-Alt. 45 mm.; long. 40 .m,m.; hmge line 19 mm.; diameter 14 mm. 

This variety is characterized by its broad, low fasciculi and light color. Type, 

No. 150207, U.S. Nat. Mus., from U.S. F. C. Sta. 3313. Iliuliuk Harbor, Unalaska, 

68 fathoms, 42. 7° bottom temperature. 

RANGE. 

Living. U. S. F. C. Stas. 3311, 3313, 3318, 3321, Bering Sea, m 54 to 85 fathoms 

(U. S. Fish Commission). 

PECTEN ( .. lEQUIPECTEN) PALMERI Dall. 

Pl. L, figs. 2, 2a, 3, and 3a. 

1897. Pecten palmeri Dall, Nautilus, vol. 11, No. 8, Dec., 1897, p. 85. 

The original description is as follows: 

Description.-" Shell thin, orbicular, compressed~ equilateral, white to yellowish 

brown, with conce,ntric or zig-zag narrow bands or flecks of dark rose color; 15 

strong ribs rounded in the young, mesially keeled and longitudinally threaded in the 
RECENT PECTENS. 137 

adult, separated by narrower channeled interspaces, each ~ith a mesial thread; all 

crossed by lamellose, concentric, rather sparsely distributed elevated lines; submargins and ears closely radially threaded with imbricated threads. Both valves 

similarly sculptured." 

Dimensions.-Alt. 47.~) mm.; long. 53 mm.; diameter about 20 mm. 

This species is easily distinguishable by its flat, orbicular disk and peculiar 

sculpture. It is known only in the recent faunas, and is found near the head of the 

Gulf of California, from whence the type and several other valves were obtained by 

Dr. E. Palmer some years ago. 

RANGE. 

Living. Near head of Gulf of California (E. Palmer). 

, PECTEN (PLAGIOCTENIUM) PAUCICOSTATUS Carpenter. 

Pl. XXXIX, figs. 3, 3a, and 4. 

1863. Pecten paucicostatus Carpenter, Brit. Assn. Rept., 1863, p. 645. 

1865. Pec,ten paucicostatus Carpenter, Ann. and Mag. Nat. H1st., 3d ser., vol. 15, 1865, p. 179. 

1888. Pecten paucicostatus Carpenter, Kuster and Kobelt, · Conch.-Cab., v9l. 17, pt. 2, Spondylus und 

Pecten, no. 9, p. 281. 

Descri_ption.-Shell averaging about 35 millimeters in altitude, longer than high, 

subequivalve, moderately ventricose; thick-shelled; margins smooth. Right valve 

subequilateral, slightly more ventricose than the left; ribs 12 to 14, prominent, 

convex-topped, subangular; interspaces slightly wider than the ribs, somewhat 

rounded; incremental sculpture fine and regular, not looped; hinge line' about fivesevenths length of disk; ears moderately prominent; anterior ear with about five 

prominent radiating ridges and numerous incremental lines; byssal notch prominent; 

posterior ear similar to anterior in sculpture, except that it is not quite so pronounced 

as in the latter. Left valve with ·prominent subangular ribs, slightly narrower than 

those of the right valve; interspaces correspondingly wider and fiat-bottomed; ears 

similarly sculptured to those of right valve. 

Dimensions.-Alt. 34.5 mm.; long. 37 mm.; hinge line 25 mm.; diameter 13 mm. 

The specimen described is No. 15643, U. S. N. M. It is dark brown in color, 

with no patterns or blotches. This species is distinguishable from P. latia'ttritus 

and varieties by its much heavier shell, dark uniform color, shorter hinge line, and 

fine uniform concentric lines. The type is labeled "Santa Barbara" by Jewett, but 

is unquestionably from the Gulf of California, as no species with its characteristics 

are known outside of the tropical fauna. Besides, ~f ewett was known to be quite 

careless regarding· the locHlities of his specimens. 

RANGE. 

Living. Gulf of California (Jewett, Stearns). 
138 TERTIARY AND · QUATERNARY PECTENS OF CALIFORNIA. 

PECTEN (PsEUDAMUSIUM) DAVIDSON! Dall. 

Pl. L, figs 4 and 4a. 

1897. Pecten Davidsoni Dall, Nautilus, vol. 11, No.8, Dec., 1897, p. 86. 

1902. Pecten Davidsoni Dall, Proc. U. S. Nat. Mus., vol. 24, 1902, p. 559, pl. 40, figs. 5, 6. 

1904. Pecten davidsoni Dall, Keep, "'Test Am. Shells, p. 41, figs. 21a., 21b. 

The original de~cription is as follows: 

Description.-" Shell small, suborbicular, compressed, waxen · white, the left 

valve with 21 rounded ribs~ surmounted by (when not worn off) continuous rows of 

minute subglobular scales, the interspaees wider, flat, and perfectly smooth, ears 

very small, the anterior with five or six imbricated radii; sculpture obsolete near 

the umbones; right valve sculptured with fafnt concentric impressed lines over the 

whole surface, and distally with numerous minute, obsolete, fine, scaly riblets; 

posterior ear transversely striated, very small, anterior one with four or five scaly 

radii, a well-marked sinus leaving an imbricated fasciole and no ctenolium. Interior 

polished, the left valve fluted internally in harmony with the external ribs." 

Dimensions.-Alt. 14 mm.; long. 14 mm.; diameter 3.5 mm. 

This little shell somewhat re~embles P. alaskensis externally, but lacks the 

r!:tdiating lirre internally, is smaller, and has faint radiating sculpture on the right 

valve, which is wanting in P. alaskensis. · 

This deep sea form is known only in the living fauna. The type (U. S. N. M., 

1077 4 7) is from the Davidson Bank, Alaska, in 280 fathoms, green-mud bottom. 

RANGE. 

Living. Davidson Bank, Alaska, 280 fathoms; north of Unalaska, in Bering Sea., 

351 fathoms (U. S. Fish Commission). 

PECTEN (PsEUDAMUSIUM) RANDOLPHI Dall. 

Pl. XL VIII, figs. 2 and 2a. 

1897. Pecten Randolphi Dall, Nautilus, vol. 11, No. 8, Dec., 1897, p. 86. 

1902. Pecten Randolphi Dall, Proc. U. S. Nat. Mus., vol. 24, 1902, p. 559, pl. 40, fig. 2. 

1904. Pecten randolphi Dall, Keep, West Am. Shells, p. 41. 

The original description is as follows: 

Description.-" Shell small; thin, glassy, unsculptured, except by minute ~ Oam.ptonectes' striation which covers both valves, and more or less obscure concentric 

undulations which are most distinct on the right valve near the umbo, and in some 

specimens altogether absent; hinge straight and short, anterior ears distinct, posterior 

ears not defined by any fold or sinus, outlipe suborbicular, valves compressed, especially the right one; right anterior ear with six small imbricated radii above, below 

a wide, transversely striated fasciole derived from a well-marked byssal i:linus; ctenolimn with four or five functional spines." 

Dimensions.-Alt. 27.5 mm.; long. 26 mm.; diameter 5 mm. 

This species is the living representative of the group consisting of the three very 

closely allied, if not identical forms, P. peckhami, P. pedroanus, and P. randolphi. 

The poor state of preservation of the fossil specimens precludes any definite state-
RECENT PECTENS. 13~ 

ment as to their equivalence, but from the large amount of material examined it is 

clearly evident that the three are very closely related. P. peckhami averages smaller 

than the other two and has usually only four radials on the right anterior ear, while 

P. pedroanus is the largest of the group and is generally much more prominently 

undulated than the others. The three species are so much alike, at any rate, that 

with the usually poor state of preservation of the Miocene fossil forms it would be 

impossible to make any definite distinctions in 99 per cent of the cases that have fallen 

under the observation of the writer. This being true, it is quite evident that the two 

forms, P. pedroan1ts and P'. pecltlutJn'i, which heretofore have always been considered 

diagnostic species of the ~1iocene, at once lose their value as agents of correlation. 

A further study of well-preserved fossil material, if any is ever-obtained, will undoubtedly tend to make clear the relations existing between the members of this very 

interesting little group. 

The type of P. randolphi (U. S. N. M., 107749) was dredged by the U. S. Fish 

Commission steamer Albatross off Destruction Island, Washington, in 516 fathoms, 

bottom temperature, 38° F. RANG~ 

Living. Bering Sea to West Mexico, in 225 to 1,005 fathoms (U. S. Fish 

CommisRion.) 

PECTEN (PSEUDAMUSIUM) RANDOLPH! Dall var. TILLAMOOKENSIS n. var. 

Pl. XL VIII, figs. 3 and 3a. 

scription.-~hell resembling ]>. randolphi in outline and general characteristics. Disk ornamented by numerous more or less prominent, fine, radiating 

ridges, microscopic radiating strirn, and incremental lines of varying prominence. 

The radiating ridges are narrow and thread-like, and appear to be more prominent 

anteriorly and near the lines of interrupted growth; the ribs are affected similarly 

to the disk by the interruptions in growth. The microscopic strirn cover the 

whole surface of the disk and ribs and in a general way radiate from the umbo, 

but are seldom parallel to the ribs; on the portion of the disk and ear posterior 

to the umbo the strirn are perpendicular to the lines of growth and are thus 

nearly parallel and not radiating. The right anterior ear has from 6 to 12 

prominently imbricated radials. 

Dimensions.-Alt. 30 mm.; long. 30 mm.; hinge line 17 mm.; diameter 7 mm. 

This variety appears to combine some of the characters of I>. vancouverensis 

with P. rctndolphi, having the prominent radial sculpture of the former and the 

relatively large, undulated disk of the latter; the ears in P. var. tillamt;okensis 

are sculptured ·more nearly like the former, having from 1 to 6 more radials 

than P. randolphi. 

This variety generally occurs in deeper water, along the northwestern eoast, 

than the typical form, being found at depths of from 400 to 800 fathoms. 

The type, U. S. N. M. 150233, is from off Tillamook Bay, Oregon, at 

U. S. F. C. Sta. 3346, at a depth of 786 fathoms. 

RANGE. 

Living. From north of Unalaska, 351 fathoms, to off Tillamook Bay, 736 

fathoms. (0. S. Fish Commission.) 
I • 

140 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

PECTEN (PsEUDAMUSIUM) v ANCOUVERENSIS Whiteaves. 

Pl. I .. II, figs. 3 and 3a. 

1886. Pecten caurinus Dall (not Gould), Bull. Mus. Comp. Zool., vol. 12, 1886, p. 216, pl. 5, fig. 4 

(supposed young of P. caurinus). 

1887. Pecten (Pseudamusium) Alaskensis Whiteaves (not Dall), Trans. Roy. Soc. Canada, vol. 4, sec. 

4, for 1886, 1887, p. 119. · 

1889. Pecten caurinus Dall (not Gould), Bull. U. S. Nat. Mus., No. 37, 1889, pl. 5, fig. 4 (supposed 

young of P. caurinus). 

1893. Pecten (Pseudamusium) Vancouverensis Whiteaves, Ottawa Naturalist, vol. 7 ( being vol. 9, 

Trans. Ottawa Field-Nat. Club), 1893, p. 133, pl. 1, figs. 1, 1a. 

1893. Pecten (Pseudamusium) Vancouverensi8 Whiteaves, Newcombe, Bull. Nat. Hist. Soc. Brit. Columbia, 1893, art. 5, p. 53. 

1895. Pecten (P~eudarnusium) Vancouverensis Whiteaves, Taylor, Tran13. Roy. Soc. Canada, 2d ser., 

vol. 1,1 1895, sec. 4, p. 26. 

1904. Pecten vancou'Verensis Whiteaves, Keep, West Am. Shells, p. 41. 

The original description is as follows: 

Descnpt-ion.-"Shell small [averaging about 7.5 millimeters in altitude], equi 

valved, compressed lenticularly, both valves being equally convex, ovately subcircular in outline apart from the ears and rather oblique; valves extremely thin and 

fragile, translucent and almost transparent, pale born color with a· slightly yellowish 

hue. BeakR placed a little behind the midlengtb; hinge line straight and very long; 

ears unequal in size, the posterior pair, which are much smaller than the anterior, 

ali~e, indistinctly defined, and merging gradually and imperceptibly into the general 

convexity and n1arginal contour of that side of each valve; anterior ears large, subtriangular, prolonged laterally, and longer than high, distinctly defined, that of the 

left valve somewhat convex in outline above and concave below, that of the right 

valve w.ith a deep and acutely angular byssal sinus at its base. . · 

"'Surface marked Qy densely crowded and exceedingly minute, irregular, and 

ra..rely continuous, but, on the whole, radiating, simple or bifurcating raised lines, 

also by comparatively large, regularly disposed, and distant squamose radii. In the 

center of each valve the minute a.nd nonsquamose raised lines are essentially parallel 

to the larger squamose radii, but on th.e sides the former are disposed obliquely to 

the latter. The surface of the anterior ear of each valve is minutely cancellated with 

extremely minute raised lines, which are almost parallel to the binge line, in addition 

to the ·coarser cross lines. The whole sculpture of the exterior of the test is far too 

minute to be clearly seen without the aid of a microscope or powerful simple. lens, 

but under either of these a few faint concentric lines of growth are also visible." 

Dimensions.-Alt. 7.5 mm.; long. 7. 75 mm.; diameter 2.25 mm. 

This beautiful little Pecten is ea~:dly distinguishable from the other members of 

the same group by its smaller size when adult, fine radiating lines of sculpture 

externally, and by its relatively longer binge line. 

RANGE. 

Living. Sitka Harbor, 12 fathoms (Dall); Forward Inlet, Quatsino Sound (Dawson); Departure Bay (Taylor, Macoun); off San Pedro, Los Angeles County, 

200 fathoms (Oldroyd); Avalon Harbor, Catalina Island, 15 fathoms (Arnold). 
DESCRIPTIONS O.If SUBGENERA AND SPECIES. 141 

UNIDENTIFIABLE PECTENS. 

PECTEJN CATILLIFORMIS Conrad. 

1856. Pecten catilliforrnis Conrad, Pac. R. R. :Rept., vol. 5, p. 329, pl. 9, fig. 83. 

1888. Pecten catilliformis Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., for 1887, p. 257 (in 

part). 

1898. Pecten catilliformis Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, p. 700. 

Orig,inal description and notes.-" Orbicular~ plano-convex, with radiating 

~trire and distinct rounded ribs; ears equal. 

"This large Pecten has such a general resemblance to P. 1nadison,£us Say, of 

the Virginia J\'liocene, that I have no doubt it existed at the same period, or at 

least after the Eocene. There is none such now living on the coast of California, 

and none in the Eocene, of this group o£ large pectens, which occur almost 

everywhere in the Miocene deposits of the Atlantic slope. 

"Locality.-Ocoya Creek [Kern County]." . 

The type of this species was the internal cast of some large Lyropecten ( ?) 

probably allied to crassicardo, estrellanus, or bowersi. According to Dall the type 

is unknown as the species was described by Conrad from drawings made by Prof. 

W. P. BJake. The figure in the Pacific Railroad Report is. so poor and the 

description so meager that it is , probable the species will remain for a long time 

unrecognized. 

PECTJ<JN NEV AD ANUS Conrad. 

1856. Pecten nevadanus Conrad, Pac. R. R. Rept., vol. 5, p. 329, pL 8, fig. 77. 

1888. Pecten nevadan'u.s Conrad, Cooper, Seventh Ann. Rept. Cal. St. Min., for 1887, p. 258 (in part). 

1898. Pecten ne'Vadanus Conrad, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 700. 

Originctl description and notes.-" Ovate, flat or slightly concave; ribs 17, large, 

flattened on the back; interstices_ strongly wrinkled transversely. 

"This shell is so nearly allied toN. (should be P.) IIumphreysii of Maryland 

that, taken in connection with P. catilli;formis, * * * it may be regarded as a 

Miocene species. The strata in which they occur may safely be referred to that 

period. 

"Locality.--Ocoya Creek [Kern County]." 

This· species, like the last, was, according to Dall, described by Conrad from 

one of Professor Blake~s drawing·s of an external mold. The figure and description 

in the Pacific Railroad Report appears to fit P. bowersi ,quite closely. The size 

of the shell, number and shape of ribs, and the characteristically· sculptured byssal 

area are similar in the two species, but the writer has hesitated to place the 

latter in the synonymy of P. nevada,nus, owing to the uncertainty of using so 

few characteristics in a definite specific determination of such importance. 

PECTEN PYXIDATUS Carpenter. 

1863. Pecten pyxidatus Carpenter, Brit. Assn. Rept., 1863, p. 667. 

1898. Pecten pyxidatus Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 711. 

This species is listed by Carpenter as having been collected by Captain Stone 

at Guaymas, Gulf of California. According to Doctor Dall this is probably a 

Chinese species. 
• 

l42 TERTIARY AND QUATERNARY PECTENS OF ·CALIFORNIA. 

PE TE~ SUBCRENATUS Carpenter. 

1863. Pecten subcrenatus Carpenter, Brit. Assn. Rept., 1863, p. 667. 

1898. Pecten subcrenatus Carpenter, Dall, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 711. 

This species is cited b 

pywidatus above referred to 

and is now unidentifiable. 

Carpenter as being a possible synonym for the P. 

It is characterized as a list name by Doctor Dall, 

ECTEN TOWNSENDI Gould. 

1863. Pecten Tm1msendi Gould, Car enter, Brit. Assn. Rept., 1863, p. 532. 

1898. Pecten Townsendi Gould, Dall, Tra11s. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. 711. 

This species is said by Carpenter to come from Puget Sound. It is also a 

list name? was never characterized, and is, consequently, now unidentifiable. 

BIBLIOGRAPHY. 

AGASSiz, Lours. 

1856. Notice of the fossil fishes: Pac. R. R. Rept., vol. 5, appendix, pp. 313-

316, pl. 1. Washington. 

ANTON, H. E. 

1839. Verzeichniss der Conchylien. Pectinea, pp. 18-20. Halle. 

ARNOLD, DELOS and RALPH. 

1902. The marine Pliocene and Pleistocene stratigraphy of the coast of southern 

California: Jour. Geol., vol. 10, No.2, pp. 117-138, pis. 1-5, figs. 1-7. 

Chicago. 

ARNOLD, RALPH. 

1903. The paleontology and stratigraphy of the marine Pliocene and Pleistocene 

of San Pedro, Cal.: Mem. Cal. Acad. Sci., vol. 3, pp. 420, pls. 37. 

San Francisco, .Tune, 1903. 

ARNOLD, RALPH, HAEHL, H. L., and. 

1904. The diabase of the Santa Cruz Mountains in San Mateo County, Cal.: 

Proc. Am. Phil. Soc., vol. 43, pp. 15-53, figs. 1-25. Philadelphia. 

AsHLEY, G. H. 

1895. The N eocene stratigraphy of the Santa Cruz Mountains, California: 

Proc. Cal. Acad. Sci., 2d ser., vol. 5, pp. 273-367, pis. 22-25. San 

.Francisco. 

BLAKE, WM. P. 

1856. Notice of remarkable strata containing the remains of Infusoria and 

Polythalamia in the Tertiary formation of Monterey, Cal.: Proc. 

Acad. Nat. Sci. Phila., vol. 7, 1855, pp. 328-331. 

BRAUNS, DAVID. 

1881. Geology of the environs of Tokio: Mem. Sci. Dept., Univ. of Tokio, 

No.4. 

BROGGER, "'· c. 

1901. Om de senglaciale og postglaciale nivaforandringer i Kristianiafeltet 

(Molluskfaunan): Norges Geologiske Undersogelse, No. 31, pp. 731, 

plates 19, text figures 69. Kristiania, 1901. 
BIBLIOGRAPHY. 143 

CARPENTER, P. P. 

1857. Report of the present state of our knowledge with regard to the J\1ollusca 

of the west coast of North America: Rept. Brit. Asso. Adv. Sci. for 

1856~ pp. 159-368, 4 pls. London. 

1864. Supplementary report on the present state of our knowledge with regard 

to the mollusks of the west coast of North America: Rept. Brit. Asso. 

Adv. Sci. for 1863, pp. 517-686. London, 1864:. 

CLARK, w. B. 

1891. Correlation papers, Eocene: Bull. U. S. Geol. Survey, No. 83. 

Washington. 

CoNRAD, T. A. 

1856. Descriptions of the fossil shells: Pae. R. R. He pt., vol. 5, appendix, pp. 

317-330, pls. 2-9. Washington. 

18fi7. Description of three new genera; twenty-three new species middle Tertiary fossils from California, and one from Texas: Proc. Acad. Nat. 

Sci. Phila., 1st ser., vol. 8, 1856, pp. 312-316. Philadelphia. 

1857. Description of the Tertiary fossils collected on the survey: Pac. R. R. 

Rept., vol. o, pt. 2, pp. 69-73, pls. 2-5. Washington. 

1857. Report on the paleontology of the survey: Pac. R. R. Rept., vol. 7, 

pt. 2, pp. 189-196, pis. 1-10. Washington. 

1863. Descriptions of new genera, subgenera and species _of Tertiary and 

Recent shells: Proc. Acad. Nat. Sci. Phila., 2d ser., vol. 6, 1862·, 

pp. 284-291. 

1867. Paleontological miscellanies: Am. Jour. Conch., vol. 3, 1867, pp. 5-7. 

Philadelphia. 

CooPER, J. G. 

1888. Catalogue of Californian fossils: Seventh Ann. Rept. Cal. State Min., 

pp. 223-308. Sacramento. 

1894. Catalogue of Californian fossils, parts 2, 3, 4, and 5: Bull. Cal. State 

Min. Bureau, No. 4. San Francisco. 

"DALL, w. H. 

1871. Diagnoses of sixty new forms of mollusks from the west coast of America 

and the north Pacific Ocean: Am. Jour. Conch., vol. 7, pp. 93-160, 

pis. 13-16. Philadelphia. 

1878. Fossil mollusks from later Tertiaries of California: Proc. U. S. Nat. 

Mus., vol. 1, pp. 10-1(). Washington. 

1886. Report on the results of dredging by the U. S. Coast Survey steamer 

"Blake." XXIX. Report on the Mollusca, pt. 1, Brachiopoda and 

Pelecypoda: Bull. Mus. Comp. Zool., vol. 12, No. 6, pp. 171-318, 

pis. 1-9, Cambridge, Mass., September, 1886. 

1889, 1903. A preliminary catalogue of the shell-bearing rna:. ine mollusks and 

brachiopods of the southeastern roast of the United States, with illustrations of many of the species: BulL U. S. Nat. Mus., No. 37, pp. 215, 

pls. 47. Washington, 1889. Reprint, pp. 232, pls. 95. Washington, 

1903. 
144 . TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 

DALL, W. H.-Continued. 

1897. New west American shell~: Nautilus, vol. 11, No. 8, pp. 85-86. Philadelphia. 

1898. The Tertiary fauna of Florida; Family Pectinidre: Trans. Wagner Free 

Inst. Sci., vol. 3, pt. 4, pp. 689-758, and plates. Philadelphia, April, 

1898. 

1898. A table of North American Tertiary horizons, correlated with one 

another and with those of western Europe, with annotations: 

Eighteenth Ann. Rept. U. S. Geol. Survey, pt. 2, pp. 323-348. 

Washington. 

1901. A new Lyropecten: Nautilus, vol. 14, No. 10, pp. 117-118. Philadelphia. 

1902. Illustrations and descriptions of new, 'unfigured, or imperfectly known 

shells, chiefly American, in the U. S. National Museum: Proc. U. S. 

Nat. Mus., .vol. 24, pp. 499-566, pls. 27-40. Washington. 

1904. Neozoic invertebrate fossils; a report on collections made by the expedition: Harriman Exped. Repts., Alaska Geol., pp. 99-122, pls. 9-10. 

DALL, W. H., and HARRIS, G. D. · 

1892. Correlation papers, Neocene: Bull. U. S. Geol. Survey, No. 84. Washington. 

DILLER, J. s. 

1896. A geological reconnaissance in northwestern Oregon: Seventeenth Ann. 

Rept. U. S. Geol. Survey, pt.l, pp. 441-520. Washington. 

FAIRBANKS, H. w. 

1904. San Luis folio: Geologic Atlas U. S., folio 101, U. S. Geol. Survey. 

Washington, June 10, 1904. 

GABB, w. M. 

1864, 18()9. Geological Survey of California, Paleontology, vol. 1, pp. 243, 

pls. 32, 1864; vol. 2, pp. 299, pls. 36, 1869. Philadelphia. 

HAEHL, H. L., and ARNOLD, RALPH. 

1904. (See Arnold, Ralph, 1904.) 

HAMLIN, HoMER. . 

1904. Water resources of the Salinas Valley, California:· Water-Sup. and Irr. 

Paper No. 89, U. S. Geol. Survey. Washington. 

HARRIS, G. D., DALL, W. H., and. 

1892. (See Dall, 1892.) 

JACKSON, R. T. 

1890. Phylogeny of the Pelecypoda: Mem. Bost. Soc. Nat. Hist., vol. 4, No. 8. 

Boston. 

KEEP' JOSIAH. 

1892. West Coast Shells, pp. 230, figs. 182. San Francisco. 

1904. West American Shells: a description in familiar terms of the principal 

marine, fresh-water, and land mollusks of the United States found 

west of the Rocky Mountains, including. those of British Columbia 

and Alaska, pp. 360, text . figs. 303. The Whitaker & Ray Co., San 

Francisco. 

KoBELT, W., KusTER, C. H., and. 

1888. (See Kuster, C. H., 1888.) 
BIBLIOGRAPHY. 145 

KusTER, C. H., and KoBELT, W. 

1888. Systematisches Conchylien-Cabinet (Martini und Chemnitz) Die Gattungen 

Spondylus und Pecten, pp. 296, pis. 72. Bauer & Raspe, Nurnberg, 

1888. 

LAWSON, A. c. 

1893. The Post-Pliocene diastrophism of the coast of southern California: 

Bull. Dept. Geol., Univ. Cal., vol. 1, No. 4, pp. 115-160, pis. 8-9. 

Berkel~y. 

1894. The geomorphogeny of the coast of northern California: Bull. Dept. 

Geol., lJniv'. Cal., vol. 1, No. 8, pp. 241-272. Berkeley. 

18!15. Sketch of the geology of the San Franciseo peninsula: Fifteenth Ann. 

Rept. U. S. Geol. Survey, 1893-9~~, pp. 399-476, pls. 5-12. Washington. 

MERRIAl\1, J. c. 

1896. Note on two Tertiary faunas from the rocks of the southern coast of 

Vancouver Island: Bull. Dept. Geol., Univ. Cal., vol. 2, No.3, pp. 101-

108. Berkeley. 

1897. The geologic relations of the J\1artinez group of California at the typical 

locality: Jour. Geol., vol. 5, No. 8, November-December, 1897, pp. 

767-775. 

1898. The distribution of the N eocene sea urchins of middle California and its 

bearing on the classification of the Neocene formations: Bull. Dept. 

Geol., Univ. Cal., vol. 2, No. 4, pp. 109-118. Berkeley. 

1900. Lists of fossils in "Oil and Gas Yielding Formations of California," by 

vV. L. Watts: Bull. Cal. State Min. Bureau, No. 19, pp. 218-224. 

Sacramento. 

1904. A note on the fauna of the lower Miocene in California: Bull. Dept. 

Geol., Univ. Cal., vol. 3, No. 16, pp. 377-381. Berkeley. 

NEWCOMBE, c. F. 

1893. Report on the marine shells of British Columbia: Bull. Nat. Hist. Soc. 

British Columbia, art. 5, -pp. 29-72. Richard Wolfenden, Victoria. 

OsMONT, VANCE C. 

1905. A geological section of the coast ranges north of the bay of San 

Francisco: Bull. Dept. Geol., Univ. Cal., vol. 4, No. 3, pp. 39-87, 

pls. 6-7. 

1905. Areas of the California N eocene: Bull. Dept. Geol., U niv. Cal., vol. 4, 

No. 4, pp. 89-100, pis. 8-11. 

pHILIPPI, R. A. 

1~45. Abbildungen und Beschreibungen neuer oder wenig gekannter Conchylien, Bd. 1, Pecten, pp. 201-204, taf. viii, 6. Cassel. 

REEVE, L. A. 

1855. Conchologia Iconiea, vol. 8, l\1onograph of the genus Pecten, species 

1-176, pls. 1-35. London. 

RIVERS, J. J. 

1904. Descriptions of some undescribed fossil shells of Pleistocene and Pliocene formations of the Santa Monica range: Bull. So. Cal. A~ad. 

Sci., vol. 3, No. 5, J\ilay, 1904, pp. 69-72, figs. 1-4. Los Angeles. 

17260-No. 47-06-10 
146 TERTIARY AND QUA'l'ERNARY PECTENS OF CALIFORNIA. 

SowERBY, G. B. 

1835. Descriptions of new species of shells in the collection of Mr. Cuming: 

Proc. Zool. Soc. Lon d., 1835, pp. 109-112. London. 

1843. Thesaurus Conchyliorum, vol. 1, Monograph of the genus Pecten, pp. 

45-82, pls. 12-20. London. 

-SowERBY, JAMEs. 

1829. The Mineral Conchology of Great Britain. (Continued by ~Tames D. C. 

Sowerby.) Vol. 6, + index to vols. 1-6, pp. 250. London. 

STANTON, T. w. 

1896. The faunal relations of the Eocene and upper Cretaceous on the Pacific 

Coast: Seventeenth Ann. Rept, U. S. Geol. Survey, pt. 1, pp. 1005-

1060, pls. 63-67. Washington. 

TAYLOR, GEORGE w. 

1895. Preliminary catalogue of the marine Mollusca of the Pacific -Coast of 

Canada, with notes on their distribution: Trans. Roy. Soc. Canada, 

2d ser .. , vol. 1, sec. 4, pp. 17-100. Ottawa. 

TRASK, J. B. 

1855. Descriptions of Californian fossil shells: Proc. Cal. Acad. Nat. Sci., 

vol. 1, pp. · 40-42. San Francisco. 

TURNER, H. w. 

1898. Notes on some igneous, metamorphic, and sedimentary rocks of the 

Coast Ranges of California: Jour. Geol., V<?L 6, pp. 483-499. Chicago. 

VAUGHAN, T. w. 

1900. The Eocene and Oligocene coral faunas of the United States: Mon. 

U. S. Geol. Survey, vol. 39, pp. 263, pls. 24. Washington. 

VERRILL, A. E. 

1897. A study of the family Pectinidre, with a revision of the genera and 

subgenera: Trans. Conn. Acad. Sci., vol. 10, pp. 41-96, pls. 16-21. 

"vVEAVER, CHARLES E. 

1905. _Contribution to the paleontology of the Martinez group: Bull. Dept. 

Geol., Univ. Cal., vol. 4, No. 5, pp. 101-123, pls .. 12-13. 

WEEKS, F. B. 

1902. North American geologic formation .names; bibliography, synonymy, 

and distribution: Bull. U. S. Geol. Survey, No. 191, pp. 448. 

W asbington. 

w HITEA YES, .T. F. 

1887. On some marine invertebrata dredged, etc., in British Columbian waters: 

Trans. Roy. Soc. Canada, vol. 4, sec. 4, pp. 111-137. Montreal. 

1893. Notes on some marine Invertebrata from the coast of British Columbia: 

Ottawa Nat., vol. 7 (being vol. 9 Trans. Ottawa Field Nat. Club), 

pp. 133-137, pl. 1. Ottawa. · 

WHITNEY, J. D: 

1869. Geological Survey of California, Paleontology, vol. 2, preface, pp. 

vii-xiv. Philadelphia. 

WILLIAMSON, MRS. lVl. B. 

1902. A monograph on Pecten- mquisu2catus Carpenter: BulL So. Cal. Acad. 

Sci., vol. 1, No. 5·, May 1, 1902, pp. 51-64, pls. 4-6. Los Angeles. 
PLAT]] II TO LIII. 

147 
PLATE II. 

·EOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG.l.· Pecten (Chlamys) calkinsi n. sp. U. O.a Ootype____________________________________ 51 

Exterior of imperfect right valve; altitude 29 mm. Tejon formation (Eocene), Sisar 

Valley, Ventura County, Cal. (S.)a 

FIG. 2. Pecten ( Chlamys) calkinsi n. sp. U. C. Type ______ ... _ ... ____ ....... _. _ .. ____ . _ .. _ _ 51 

Exterior of imperfect left valve; altitude 45 mm. Same locality as fig. 1. (S.) 

FIG. 3. Pecten (Chlamys) landesi n. sp. U.S.N. M. 164926. Type.......................... 51 

Exterior of right valve; altitude 31 mm. Eocene, Little Falls, Lewis County, Wash. 

(M.P.) 

FIG. . Pecten ( Chlamys) landesi n. sp. U. S. N. M. 164926. Ootype ___ .. _ .. ___ ... _ ..... _.__ 51 

Exterior of left valve; altitude 22.5 mm. · Same locality as fig. 3. (M. P.) 

FIG. 5. Pecten ( Chlamys) landesi n. sp. U. · N. M. 164926. Ootype _________ ... ____ ....... _ 51 

Exterior of right valve ( coarse-ribb d form); altitude 34 mm. Same locality as last. 

(M.~) . 

FIG. 6. Pecten ( Chlamys) proavus n. sp. U. S. N. M. 164930. Type _______ . ______ . ____ ._____ 52 

Mold of interior of left valve, showi ' g portion of external surface sculpture; altitude 

38 mm. Eocene, between headw~ters of San Lorenzo River and Pescadero Creek, 

San Mateo County, Cal. (M. B.) I . FIG. 7. Same specimen as fig. 6 _ _ __ _ _ _ _ _ _ _ _ _______ . __ ... ________________ . ____ . _ .. __ .. _ _ _ _ 52 

Portion of disk showing sculpture; e larged twice. 

FIG. 8. Pecten ( Chlamys) proavus n. sp. U. S. N. M. 164930. Ootype ___ .. _ .. ___ . __ . __ . __ . _ _ 52 

Fragment of a large specimen. Sam . locality as fig. 6. 

FIG . . 9. Pecten (Propeamusiurn) interrad·iatus p abb. Type ____ . _____ .. ___ ... _____ ... __ .. _._.. 53 

Exterior of left valve; altitude 25 mrp- Copied, with slight alteration, from Pal. Cal., 

vol. 2, pl. 33, fig. 98. Tejon form tion (Eocene), New Idria, San Benito County, 

Cal. 

FIG. 10. Same specimen as fig. 9 _____ . __ . . _ . ____ . ____________ . ____ .. ___________ . ____ .... _ 53 

Mold of interior of left valve; altitu e 25 mm. Copie~, with slight alteration, from 

Pal. Cal., vol. 2, pl. 33, fig. 98. 

FIG. 11. Pecten ( Propeamusium) interradiatus Gabb _____ . ______ . ________ . _______ . _. __ . __ ... _ 53 

Outline of hinge line and ear of right valve. Copied, with . slight alteration, from 

Pal. Cal., vol. 2, pl. 33, fig. 98a. I 

aThe initials immediately following the name of the specimen are those of the institution or individual to 

which the specimen belongs, and to which referenc is made in the introduction; the initials or letter at the conclusion of the expl_anation indicates the artist who retouched the figure. 

148 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. II 

11 

a 

10 9 

2 

8 

7 

4 

5 

6 

CENE PECTENS. 
PLATE III. 

OLIGOCENE-MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten (Propeamusium) clallamensis n. sp. U.S.N. M.164923. Ootype________________ 57 

Impt-rfect mold of exterior of right valve; hinge line 6.5 mm., X 3. - Oligocene-Mioeene, 

Loc. 4070, Bean Point, King County, Wash. (M. P.) 

FIG. 2. Pecten (Prop amu:~ium) clallamensis n. sp. U. S. N. M. 164922. Ootype ____ · _______ ... _ 57 

Imperfect mold of interior of left valve; altitude 7 mm., X 3. Oligocene-Mioeene, Loc. 

4100, 1t miles east of Pillar Point, Clallam County, Wash. (M. B.) 

FIG. 3. Pecten ( Propeamuswm) clallamens-is n. sp. U. S. N. M. 164922. Type _. _ .... __ ........ 57 

Mold of exterior of left valve; altitude 10 rom., X 3. Same locality as :fig. 2. (M.P.) 

FIG. 3tz, Same specimen as fig. 3 ____ .. _ ...... __ ... _. _ ......... __ ... _ .. ___ ... ____ . ___ ... _ _ _ _ _ 57 

Portion of disk (not mold) enlarged 6 times. 

FIG .. 4._ l!ecten ( Propeamusium) waylandi n. sp. U. B. N. M. 164924. Type ..... _ .. _____ . ___ . . 58 

Imperfect mold of exterior of left valve; longitude 7 rom., X 3. Same locality (4100) as 

:fig. 2. (M. B.) 

FIG. 5. Pecten ( Propeamusium) waylandi. n. sp. U._ S. ~ M. 164924. Co type .. __ ..... _........ 58 

Mold of interior of right valve;· altitude 10 mm., X 3. · Oligocene-Miocene, Loc. 4115, 

2t miles west of Gettysburg, Clallam County, Wash.. (M. B.) 

FIG. 6. Pecten ( Pseudamusium) peckhami Gab b. Type __ --.--- __ . __________ ............. _...... 56 

Exterior of left valve; altitude 21 mm. Copied from Pal._ Cal.,, vol. 2, pl. 16, :fig. 19. Spedmen from Ojai ranch, Ventura County, Cal.. 

FIG. 7. Pecten (Pseudamusium) peckhami Gabb. Ootype. ----~----------- ------------------ · 56 

Outline of hinge line and ears of right valve.. Copied from Pal. Cal., vol. 2, pl. 16, :fig. 19a. 

_ Same locality as :fig. 6. 

FIG. 8. Pecten (Pseudamusium) peckhami Gab b. U. S. N. M. 164839 _____________ . __ .......... 56 

Casts of right and left valvesin matrix. Monterey shale (Miocene), southeast of Pinole, 

Contra Costa County, Cal. (M. P.) 

FIG. 9. Pecten (Chlamys) brannerin. sp. L. S. J. U. Plastotype .. -----------------.--.---------. 55 

Cast from imperfect mold (type) of left valve; hinge line 33 rom. Vaquero formation 

(lower Miocene), Tuff Hill, near Stanford University, Santa Clara County, Cal. (M. P.) 

FIG. 10. Pecten ( Chlamys) branneri n. sp. L. S. J. U _. ____________ .. ________ .. __ ..... _...... 55 

Cast from fragment of mold of disk, showing sculpture. Same locality as :fig. 9. (M.P.) 

FIG. 11. Pecten (Chlamys) brannerin. sp. L. S. J. U --------------------------------·· ·----- 55 

Cast from fragment of mold of disk, showing sculpture. Same locality as :fig. 9. (M.P.) 

FIG. 12. Pecten (Pecten) sanct:ecruzensisn. sp. L. J. F. H. Ootype___________________________ 54 

Exterior of portion of right valve; longitude 48 mm. San Lorenzo formation (Oligocene), 

Bear Creek, Santa Cruz County, Cal. (M. B.) 

FIG. 13. Pecten (Pecten) sanct:ecruzensis n. sp. L. S. J. U. Plastotype ____ . ~ . . . . . . . . . . . . . . . . . . 54 

Exterior of cast from mold (type) of left valve; altitude 52 rom. San Lorenzo formation 

(Oligocene), Twobar Creek, l::lanta Cruz County, Cal. (M. B.) 

l50 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. Ill 

I~~ 7 

4 

6 

12 

3 

10 

13 

2 

8 9 11 

OLIGOCENE-MIOCENE PECTENS. 
PLATE IV. 

MIOCENE AND PLIOCENE PECTENS. 

[Uuless otherwise stated all figures are approximately natural size.] 

FIG.l. Pecten (Pecten) carrizoensisn. sp. D. A. Type .. · --- ------------- ------ -------------

Exterior of right valve; altitude 36 mm. Carrizo formation (Miocene), Alverson Canyon, San Diego County, Cal. (M. B.) 

FIG. la. Same specimen as fig. 1 . __ .. _ ..... _ .. __ .. __ ..... _ . ~ . _ ... _ .. _ ...... _ .. ____ ........ . 

Exterior of left valve. 

Fw: lb. Same specimen as fig. 1 __ ..... .. .. _____ .. _ .. _ .. ____ ... __ .. _ . ___ .. _ ... _ .. __ .. ____ _ 

Profile of both valves viewed from rear. (M. P.) 

Fro. 2. Pecten (Pecten) carrizoensisn. sp. U.S.N. M.l64847~----------·-------------------­

Exterior of left valve; altitude 63 mm. Miocene, Santa Rosalia, Lower California. (M. P.) 

FIG. 3. Pecten (Pecten) carrizoensisn. sp. U.S.N. M.l64848 _______________________________ _ 

Exterior of imperfect right valve; longitude 44 mm. Same locality as fig. 2. (M. B.) 

Fw. 3a. Same specimen as fig. 3 ... ____ . ____ . _ ... __ . ____ .. __ · __ . _. __ . __ . ___ . ____ . _ ... __ .. __ _ 

Profile of right valve viewed from front. (M. P.) 

Fro. 4. Pecten (Pecten) coalingaensisn. sp. L. S. J. U. Type __________________________ _____ _ 

Exterior of slightly distorted right valve; altitude 47 mm. Lower Pliocene, Coalinga, 

Fresno County, Cal. (M. B.) 

Fro. 4a. Same specimen as fig. 4 ... __ .... _ .. ______ .... ___ ... _ ...... - - -.... - ---... -.... - -. --

Profile of right valve viewed from rear. (M. P.) 

FIG. 5. Pecten (Pecten) coalingaensisn. sp. C. A. S. Ootype __ -·--·----------------·-·-·--· 

Exterior of left valve; altitude 35 mm. Lower Pliocene, Kreyenhagen's ranch, Fresno 

County, Cal. (S.) 

152 

Page. 

59 

59 

59 

59 

59 

59 

97 

97 

97 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. IV 

2 

3 4 

MIOCENE AND PLIOCENE PECTENS. 
PLA .TE V. 

MIOCENE .PECTENS. 

[Unless otherwise stated all figures are :approxlmately natural size.] 

Page. 

Fw. 1. Pecten (Pecten) keepi n. ·sp. D. A. Type---·--- ~~ --- -~ -------------------------- 60 

Exterior of somewhat imperfect and worn left valve.; altitude :75 mm. Miocene, Carrizo 

Creek district, San Diego County, Cal. (M. P.) 

FIG. 2. Pecten ( Patinopecten) dilleri . Dall. U. S. N. M. 164846. co~ype . ___________ . _. ___ .... _ 62 

Exterior of imperfect tight valve; altitude (restored) 180 mrtL Upper Mioeene or lower 

Pliocene, Eel River, Humboldt County, Cal. (M .. B.) 

FIG. 3. Pecten (Chlamys) sespeensis var. hydei n. var. D. A. Type .. ·------------------------ 69 

Exterior of right valve, anterior ear missing; altitude 46 mm. ' Vaqueros sandstone 

(lower Miocene), Lynch's Mountain, Monterey County, Cal. (M. B.) 

FIG. 3a. Same specimen as fig. 3 ____ ~ . ____ ~ ______ • _. __ ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 69 

Exterior of left valve, anterior ear missing. (M. B.) 

FIG. 3b. Same specimen as fig. 3 -----·-·------- ·-------~--------------------- ------------- 69 

Profile of both valves as viewed from the ·rear. (M. P.) 

154 
PROFESSIONAL PAPER NO. 47 PL. V 

U. S. GEOLOGICAL SURVEY 

3 

2 

MIOCENE PECTENS. 
PLATE VI. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Puge. FIG. 1. Pecten (Pecten) keepi n. sp. D. A. Type ................... _ .... .... . _ . _ ... _ . . . . . . . 60 

Exterior of right valve; altitude 75 mm. Carrizo formation (Miocene), Carrizo Creek 

district, San Diego County, Cal. ( M. P.) 

FIG. 1a. Same specimen as fig. i ......... ~ ..... _ . _ ..... _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 

Profile of right valve viewed from rear. ( M. P.) 

FIG. 2. Pecten (Patinopecten) coosensis Shumard. U. S. N. M. 107791..................... . ... 61 

Exterior of left valve; altitude 103 mm. Empire formation (Miocene), Coos Bay, Oreg. (M.P.) 

156 
PROFESSIONAL PAPER NO. 47 PL. VI 

U. S. GEOLOGICAL SURVEY 

2 

MIOCENE PECTENS. 
PLATE VII. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. FIG. 1. Pecten ( Patinopecten) propatulus Conrad. U. C .............. " _ . . . . . . . . . . . . . . . . . . . . . . . 64 

Mold of interior of right valve, showing a portion of the umbonal area and ears; altitude 

90 mm. Astoria formation (Miocene), Astoria, Oreg. (H.) 

FIG. 2. Pecten (Patinopecten) coosensis Shumard. U. S. N. M. 107791 . _ ........... _............ 61 

Exterior of right valve, anterior ear slightly broken; altitude 10:3 mm. Empire formation 

(Miocene), Coos Bay, Oreg. (M.P.) 

FIG. ~a. Same specimnn as fig. 2 ...... _. __ . _. _. __ . .... _. _ ... ____ ... ____ .. ___ .... __ ...... __ -- 61 

Profile of both valves, viewed from rear. 

158 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. VII 

MIOCENE PECTENS. 
PLATE. VIII. 

-MIOCENE AND PLIOCENE PECTENS. 

[Unless otherwise stated all figures are apwoximately natural size.] 

FIG. 1. Pecten ( Patinopecten) oweni n. sp. U. 0. Type _ . ___ . ______________ . _ . __ ... _ .. -.-.-

Exterior of right valve, anterior ear slightly broken; altitude 85 mm. (Upper Miocene?), Foxin's ranch, Santa Barbara County, Cal. (M. B.) 

FIG. la. Same specimen as fig. 1 __________ . ____ . ____ . ________ . __ . ___ .. ___ .. __ . _. _ ..... _ ... 

Exterior of left valve. ( M. B.) 

FIG. lb. Same specimen as fig. 1 _. ____ .. _______________ . ________________ . _______ .. _. _. _ ... 

Profile of both valves viewed from rear. (M. P.) 

FIG. 2. Pecten ( Chlamys) sespeensis n. sp. C. S. '

1

M . .B __ . __ . _ . __ . -. -.-- - - ---- ---- -. -.. -- . -- - -

Portion of mold of interior of right valve; altitude 50 rnm. Vaqueros formation (lower 

Miocene), ~espe Canyon, Ventura Colfty, Cal. (M. B.) 

FIG. 2a. Same specimen as fig. 2 ___ . ___ . ________ . _____ .. _ ... ____________ .. _ .. ___ . __ . _- . -. -

Portion of mold of interior of left valve.1 

FIG. 8. Pecten ( Chlamys} sespeensis n. sp. C. S. M. B. · Plastotype. ___________ .. _____ . _. _ .. --

Cast of exterior of slightly imperfect left valve (young); altitude 18 mm. Same locality as fig. 2. (M. B.) 

160 

Page. 

63. 

63 

63 

69 

69 

69 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. VIII 

3 

.2 

MIOCENE AND PLIOCENE PECTENS. 
PL'ATE IX. 

MIOCENE PECTENS. 

[UnleRs otherwise stated all figures are approximately natunJ size.] 

FIG. 1. Pecten ( Patinopecten) propattdus Conrad, U. S. N. M. 3558. Co type. ______________ __ _ 

Exterior of portion of right valve; altitude 100 mm. Astoria formation (Miocene), 

Astoria, Oreg. (M. B.) 

Fw. 1a. Same specimen and valve as fig. 1 ____________________________________________ -. 

Portion of disk, showing part of two ribs and included interspace, X 3. (M. B.) FIG. 2. Same specimen as fig. L __________________________ • _________________________ . ____ _ 

Exterior of portion of left valve. 

FIG. 2a. Same specimen as fig. 1, left valve __________ __________ . _________________________ _ 

Portion of disk, showing part of three ribs anq included interspaces, X 3. (M. B.) 

162 

Page. 

64 

64 

64 

64 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. IX 

MIOCENE PECTENS. 
PLATE X. 

MIOCENE AND PLIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately n,atural size.] 

Page. 

FIG.l. Pecten (Chlamys)jucanus Dall. U.S.N. l\1.164933.................................. 66 

Exterior of imperfect right yalve; altitude 83 mm. Miocene, coast of Strait of Juan 

de Fuca, east of Clallam Bay, Clallam County, Wash. (M. B.) , 

F.IG. 2:·

1 

Pecten ( Chlamys) fucanus Dali. U. S. N. M. 107790. Plastotype ............... _ .... _ 66 

Cast of exterior of left _valve; altitude 81 mm. Same locality as fig. 1. 

Fr(l. 2a. Same specimen as fig .. 2 .. _ ........... ___ ...... ___ . _:. _. __ .. _. __ . _ ........ ,. _... 66 

Profile of left valve viewed from front. (M. P.) 

FIG. 3. Pecten ( Chlamys) wattsi var. morani n. var. U. S. N. :i\'I. 164929. Type. ____ .......... 121 

Exterior. of imperfect right valve; altitude 63 mm. Lower. Pliocene, Moran's place, 

Priest Valley, Monterey County, Cal. (M. B.) 

FIG. 4. Pecten ( Chlain.ys) wattsi var. morani n. var. .U. S. N. M. 164929. Cotype ...... ;...... 121 

Exterior of imperfect left valve; altitude 59 mm. Same locality as fig. 3. 

FIG. 5. Pecten ( Chlamys) watt.~i var. morani n. var. U. S. N. M. 164929. _ .... _. ___ . _ ... _ .. _ _ _ 121 

Exterior of imperfect left valve; longitude 41 mm. Same locality as fig. 3. 

Fw. 6. Pecten ( Chlamys) wattsi Yar. morani n. var _ ..... __ ...... ___ ...... __ . __ ... _ ...... ___ . 121 

Exterior of imperfect left valve (young); altitude 30 mm. Same locality as fig. 3. 

164 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. X 

4 

6 

5 

MIOCENE AND PLIOCENE PECTENS. 
PLATE XI. 

MIOCENE AND . PLIOCENE PECTENS. 

[Unless otherwise stated a ll 'figures are approximately natural size.] 

Page. 

FIG. 1. Pecten ( Chlarnys) wattsi n. sp. C. A. S . . Type .... _.......... . .... . ..... .. ........... 120 

Exterior of slightly imperfect left valve; altitude 66 · mm. Lower. Pliocene, Kreyenhagen's ranch, Fresno County, Cal. (S.) 

FIG. 1a. Same specimen as fig. 1 .. . ....... ...... _ ..... __ ................. _ ........... . .... _ 120 

Profile of left valve, viewed from rear. ( M. P.) 

FIG. 2. Pecten ( Chlarnys) harnlini n. sp. U. S. N. M. 164844. Type ... . ... . . .. .... . . . __ .. _... 67 

Exterior of contorted · (lengthened) right valve; altitude 50 mm. Miocene (lower?), 

head of Slacks Canyon; Monterey County, Cal. (M. B.) 

FIG. 3. Pecten ( Chlarnys) nutteri n. sp. D. A. Type .. _ ........ ~ ... _ ...... __ ............ __ .. 67 

Exterior of slightly imperfect right valve; altitude 74 mm. Purisima formation (lower 

Pliocene), south of mouth of San Gregorio Creek, San Mateo County, Cal. (·M. B.) 

FIG. 4: Pecten ( Chlarnys) nutteri n . sp. C. S. M. B. 14125. Cotype ... __ .... ___ .. _. __ .... .. ... 67 

Exterior of slightly imperfect left valve; altitude 63 mm. Lower Pliocene, Kreyenha-. 

gen's ranch, Fresno County, Cal. (M. B.) 

FIG. 4a, Same specimen as fig. 4 . . . _ . . ..... _ ...... ___ ... ____ . . .... _. _ ......... . . __ . . _. _.... 67 

Profile of left valve, viewed from rear. 

Fw. 5. Pecten (Lyropecten) crassicardo Conrad var. harniltoni n. var. U.S. N. M. 164845. Type. 73 

Exterior of slightly contorted and imperfect right ,valve; . altitude 40 mm. Miocene, 

Alum Rock Canyon, Santa Clara County, Cal. 

FIG. 6. Pecten (Lyropecten) crar;sicardo Conrad var. hamiltoni n. var. ·u. S. N. M. 164845. 

Ootype __ .. _ .. _ .. . __ .. __ . _ . . __ .. _ . ___ ..... ___ . _ ..... ___ . _ .... ____ ......... _ . . . . . . . 73 

Exterior of imperfect ( earless) right valve; altitude 63 mm. Same locality as last. 

166 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XI 

5 

2 

6 

4 

3 

MIOCENE AND PLIOCENE PECTENS. 
PLATE XII. 

MIOCENE .PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Fw.I. Pecten (Lyropecten) bmoersi n. sp. U. C. Type ........ "----------------------------

Exterior of slightly imperfect right valve; altitude 150 mm. Miocene (lower), Santa 

Inez Canyon, Santa Barbara County, Cal. (M. B.) 

FIG. 2. Peclen(Lyropecten) bowersi n. sp. D. A .......... ·-------·---------------- - --------- -

Exterior of u~1bo and ears (the anterior somewhat imperfect) of a right yalve; hinge line 

restored 86 mm. Miocene (lower), Santa Monica Mountains, Ventura County, Cal. 

(M.P.) 

168 

Page. 

70 

70 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XII 

2 

MIOCENE PECTENS. 
PLATE XIII. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. Fm.l. Pecten (Lyropecten) bowersin. sp. U. C. Type--·---·-··-------·--·--------·--------- 70 

Exterior .of left valve, ears imperiect; altittide 150 mm. Miocene (lower), Santa Inez 

Canyon, Santa Barbara County, Cal. (H.) 

FIG. 1a. Same specimen as fig. 1 ___ ... ____ .. _ _ _ _ _ _ _ _________ . _________ . _. __ . ____ . __ _ .. _... 70 

Profile of both va:Ives viewed _from rear. ( M. P.) 

170 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XIII 

MIOCENE PECTENS. 
PLATE XIV. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

FIG. 1. Pecten (Lyropecten) perrini n. sp. L. S .. T. U. Type ____________ ---·---·---·---·----

Exterior of imperfect right valve; altitude 150 mm. Vaqueros sandstone (Miocene), 

between Morro and Toro creeks, San Luis Obispo Couqty, Cal. (M. B.) 

FIG. la. Same specimen as fig. 1 ___ . ________________ .. ______ . ___________ . __________ .. _____ _ 

Profile of both valves viewed from rear. (M. P.) 

172 

Page 

80 

80 
u. s. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XIV 

MIOCENE PECTENS. 
PLATE XV. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

Fm.l. Pecten (Lyropecten) perrini n. sp. L.S. J. U. Type. -- -· --····------ ----------- ---- 80 

Exterior of imperfect left valve; altitude 150 mm. Vaqueros sandstone (Miocene), 

between Morro and Toro creek~, San Luis Obispo County, Cal. (M. B.) 

FIG. 2. Pecten (Plagioctertium) neahensis n. sp. U.S.N. M. 5912. Type ___ . _ . . _ .... _ .... _.. 87 

Exterior of imperfect right valve; longitude 49 mm. Miocene, Strait of Fuca, east of 

Neah Bay, Clallam County, ·wash. · (M. B.) 

FIG. 2a. Same specimen as fig. 2 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 87 

Exterior of imperfect left valve. ( M. B.) 

Fw. 2b. Same specimen as fig. 2 _ _ _ _ _ _ _ _· _____________ _______ . _____ __________ . ... ___ . 87 

View of both valves from the rear. ( M. B.) . 

174 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XV 

2b 

MIOCENE PECTENS. 
PL.A_TE XVI. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures·are approximately natur!J,l size.] 

Page. 

FIG. 1. Pecten (Lyropecwn) crassicardo Conrad. U. S. N. M. 154154 ______ -________________ .... 71 

Exterior of slightly imperfect ri~ht valve; altitude 155 mm. San Pablo formation 

(Miocene), Kirker Pass, Contra Costa County, Cal. (M. B.) 

FIG. 1a. Same specimen as fig. L ______ . ______ __ ___ : _· ___ . ___ ... __ ....... . _ .. .. _ ... .. __ . ___ . _ _ _ 71 

Profile of right valve viewed from rear. (l\1. P.) 

176 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XVI 

MIOCENE PECTENS. 
PI~ ATE XVII. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

FIG. 1. Pecten ( Lyropecten) crassicordo Conrad. U. C ....... _- _-- _---- _.- _- ------ . ----- ------

Exterior of slightly imperfect right valve; altitude 97 mm. San Pablo formation (upper 

Miocene), Contra Costa County, Cal. (M. B.) 

FIG. la. Same specimen as fig. 1. _________ . _____ . _ _ _ _ ______ - _-- . - _-- .. ----- ---- ----- -------

Exterior of imperfect left valve. (M. B.) 

FIG. lb. Same specimen as fig. 1. _____ . ___ . __ . __ ·. _ . __ . _ . ________ ... _ - _ - - . ----- - - - --- -- . -- --. 

View of both valves from the rear, showing constriction of disk. (S.) 

178 

Page. 

71 

71 

71 
U.S. GEOLOG ICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XVII 

MIOCENE PECTENS. 
PLATE XVIII. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten ( Lyropecten) crassicardo Conrad. A. N. S., , Phila. Type ............. ___ . . . . . . 71 

Exterior of left valve (ears gone); altitude 135 mm. Miocene (probably upper, or San 

Pablo formation), "California." (Photograph by Ralph Arnold. Shell not coated.) 

FIG. 2. Pecten ( Lyropecten) cmssicardo Conrad. C. S. M. B. 12772 _____ . ____ .. . . . . . . . . . . . . . . . 71 

Exterior of left valve (ears gone); altitude 88 mm. Miocene, Ventura County. (S.) 

FIG. 2a. Same specimen as fig. 2 __ ~ __ . _______________________ ................. ---. -------- '71 

View of both valves from the rear, showing constriction of disk. (M. B.) 

180 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XVIII 

2 

MIOCENE PECTENS. 
PL_il_TE XIX. 

MJOCE;NE PECTE;NS. 

[Unless otherwise stated all figures ar!'l approximately na,tural size.] 

Page. 

FIG. 1. Pecten (Lyropecten) estrellanus Conrad. U. S. N. M. 164851.......................... 74 

Exterior of left valve; altitude 97 mm. Santa Margarita formation (upper Miocene), 

Wildhorse Canyon, Monterey County, Cal. _ ( M. B.) 

FIG. la. Same specimen as fig. 1. _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 

Interior of left valve. (M. B.) 

182 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XIX 

MIOCENE PECTENS. 
PI,ATE XX. 

MIOCENE AND PLIOCENE PECTENS. 

[Unl~ss otherwise stated all figureR are approximat ely natural size.] 

FIG. 1. Pect~n (Lyrope:ten) e~trellanus C~nrad. U. S. f· M. 13317. Cotype ...... -_- ........ ~ .. 

Extenor of portiOn of Imperfect ngbt valve; alt tude 90 mm. Santa Marganta formatiOn 

(upper Miocene), Estrella valley, San Luis Obispo County, Cal. (M. R) 

FIG. 2. Pecten (Lyropecten) estrellanus Conrad. C. S. M. B.12871 ................... ...... -.. . 

Exterior of very convex right valve (form described as P. volcejormis Conrad); altitude 

71 mm. San Pablo formation (upper Miocene), Coalinga, Fresno County, Cal. ( M. B.) 

FIG. 2a. Same specimen as fig. 2 .·.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .............. . 

Profile of right valve viewed from rear. (M. P.) , 

FIG. 3. Pecten estrellanus Conrad va,r. _catalinx n. var. ,D. A. Type ............... .. ..... - . . . . 

Exterior of imperfect right valve; altitude 68 rom. Upper Miocene, near Isthmus, Santa 

Catalina Island, Los Angeles County, Cal. (M. R) 

FIG. 3a. Same specimen as fig. 3 . ................. ____ .... _ -. __ - --- - - -............ ---... - - -

Profile of right valve viewed from the rear. (M. P.) 

Fm. 4. Pecten estrellamt.s Conrad var. catalinx n. var. 1 D. A.-- ... . _ ... ........ -- ... --- .... - . . 

Interior showing umbo and hinge; hinge line r 0 mm. Same locality a::l fig. 3. (M. B.) 

184 

Page. 

74 

74 

74 

76 

76 

76 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XX 

2 

MIOCENE AND PLIOCENE PECTENS. 
PLATE XXI. 

MTOCENE PECTENS. 

[Unless otherwise stated a ll figures are approximately natural size.] 

FIG. 1. Pecten (Lyropecten) estrellnnns Conrad. C. S. M. B ___ --- ___ .- .- .. ---.- . . -- ... -.. -----

Exterior of right valve (_ea:rs imperfect); altitude 77 mm. San Pablo formation (upper 

Miocene), Coalinga, Fresno County, Cal. (M. B.) , 

FIG. la. Same specimen as fig. 1 _ . ______ . ____ .... _ . _____ -- -. -- -- ---- --- -- -- . ---- ------- ---

Exterior of left valve (ears fmperfect). (M. B.) 

FIG. lb. Same specimen as fig. 1 __ :." ___ . __ .. _ . .. . _ ... _____ - . - __ --------- ------- ---- -------

View of both valves from the rear, showing constriction. (M. B.) 

FIG. 2. Pecten (Lyropect'en) estrellanus Conrad .. J., H .. w_.---- · .. --.-.-------. ---.--. -.. ----- Exterior of right. valve (ears; slightly broken); altitude· 50 mm. Miocene, Cholame 

Mountains, 40 miles ~ast of: Paso Robles, San Luis Obispo County, Cal. (M. B.) 

FIG. 2a. Same specimen as fig. 2 __ -·· ________________ . _ .. __ -.. --- .. . ---.--- . . -- ..... . ------

Exterior of left valve (ears· slightly· bro:k·en). ' 

FIG. 2b. Same specimen as fi'g. 2 ______ . ___ . ·:· ..... . . __ . ___ --- __ . ------ .. -.- .. --------- ----

Profile of both valves vfewed from rear. 

186 

Page. 

74 

74 

74 

74 

74 

74 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXI 

2 

MIOCENE PECTENS. 
PLATE XXII. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FrG. 1. Pecten (Lyropecten) rniguelensi.s n. sp. U. C. Type ________ ·------------------------- 79 

Exterior of somewhat imperfect right valve; altitude 110 mm. Miocene (lower), San 

Miguel Island, Santa Barbara County, Cal. (M. B.) 

FIG. Ia. Same specimen as fig. 1 ____________ . __ .. ____________________________________ . _ _ _ _ 79 

Exterior of somewhat imperfect left valve. (M. B.) 

FIG. lb. Same specimen as fig. l _____________ . __________ . ____________ . __________ ·.- _ _ _ _ _ _ _ _ 79 

Somewhat distorted profile of both valves viewed from rear. (M. P.) 

188 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXII 

MIOCENE PECTENS. 
PL_i\_TE XXIII. 

MIOCENE PECTEN~. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

Fra.l. Pecten (Lyropecten) miguelensis n. sp. U.S.N. M. 6397 -------------·-----------·--- 79 

Exterior of um bonal region aml imperfect ears of left valve; altitnde of fragment 

76 mm. Copied from drawing by Doctor McConnell. Mioeene, Santa Inez Mountains, Santa Barbara County, CaL 

FIG. 2. Pecten ( Lyropecten) estrellanus Conrad var. term·inus n. yar. U. C. Type. ____ - _. _ --- - - _ 77 

Exterior of right valve; altituue 70 mm. Santa Margarita formation (upper Miocene), 

Monterey County, Cal. (M. B.) 

FIG. 2a. Same specimen as fig. 2 __________ . ____ __ ____ . ___ ........ _ .. -....... - -- --- ... ---- - 77 

Profile of right valve, viewed from rear. (M.P.) 

FIG. 3. Pecten (Lyropecten) vaughani n. sp. D. A. Type .. ·-·-----------------------------"- 81 

Exterior of right valve; altitude 37 mm. Miocene (lower), Ojai Valley, Ventura 

County, Gal. (M. B.) 

FIG. 3a. Same specimen as fig. 3 .. __ ·_ . ____________ . __ __ ____ ___ ______ ____ ... ~ ........... - - -- 81 

Exterior of left valve. ( M. B.) 

FIG. 3b. Same specimen as fig. 3 ___ .. ____ .. _. __ ...... __ ..... _ .. · ....... ___ . .. __ ..... _ ..... _ _ _ 81 

Profile of both valves, viewed from the rear, showing contraction of disk. (M. P.) 

FIG. 4. Pecten (Propeamusium) stanjordensis n. sp. D. A. Type. ___ .... _.- ... __ ... : .--...... 91 

Mold of interior of right valve and cast of exterior of left valve; altitude 7 mm., X 3. 

Miocene, Burke ranch, near Stanford University, Santa Clara County, Cal. (M. B.) 

FrG. 5. Pecten ( Pseudamusium) lompicoensis n. sp. U. S. N. lYI. 164931 ..... . _ ... _ ....... _.... . 89 

Mold of exterior of contorted left Yalve; altitude 14 mm., X 3. 

Miocene shale, head of Lompico Creek, Santa Cruz County, Cal. (M. P.) 

190 

• 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXIII 

3 

4 

2 5 

MIOCENE PECTENS. 
PLATE XXIV. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.) 

Page. 

FIG. 1. Pecten (Lyropecten) magnolia Conrad. U. C --------------·------------------------ 77 

Exterior of right valve (anterior ear missing), altitude 145 mm. Vaqueros formation 

(lower Miocene), Ojai ranch, Ventura County, Cal. (S.) 

Fra. 2. Pecten (Lyropecten) magnol'ia Conrad. L. S. J. U ____ . _______________ . __ . _ _ _ _ _ _ _ _ _ 77 

Exterior of umbonal region and ears; hinge line 95 mm. Miocene (lower), between 

Morro and Toro creeks, San Luis Obispo County, Cal. 

192 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXIV 

2 

MIOCENE PECTENS. 
• 

PLATE XXV. 

MIOOEN E PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten ( Lyropecten) magnolia Conrad. U. 8. N. M. 13325. Ootype _____ . _________ . _ _ _ 77 

Exterior of vaive, showing characteristic sculpture and shape of ribs; altitude of fragment 

130 rom. Vaqueros formation (lower Miocene), Santa Inez Mountains, Santa Barbara 

County, Cal. (M. B.) 

FIG. 2. Pecten (Pla.gioclenium) cerrosensis Gabb var. mendenhalli n. var. U. S. N. M. 164849. 

Type ____ _ . ________________________________________________ . _________________ . _ _ _ _ 84 

Exterior of right valve; altitude 43 rom. Miocene, Santa Rosalia, Lower California. 

(M. B.) 

FIG. 2a. Same specimen as fig. 2 _ . _____________________ . _______________________ . _ _ _ _ _ _ _ _ _ _ _ 84 

Exterior of left valve. (M. B.) • · 

FIG. 2b. Same specimen as fig. 2 ______ . ___________ __ . ________ . __ . _____ ~ __ . _____ _ .. . _ _ _ _ _ _ _ _ _ 84 

Profile of both valves, viewed from the rear. (M.P.) 

FIG. 3. Pecten (Plagioctenium) eldridgei n. sp. U. S. N.l\1. 164850. Type .. _ .. ____ ... _....... 87 

Exterior of left valve; altitude 20 mm. San Pablo formation (upper Miocene), McKittrick district, Kern County, Cal. (M.P.) 

FIG. 3a. Same specimen as fig. 3 ..... _ .... _ ........... _ .. _ . _. _ .... _ .. ____________ ......... _ 87 

. View of interior of left valve. ( M. P.) ' 

FIG. 3b. Same specimen as fig. 3 _ .......... __ .. _ ......... __ . _ ... _ . _ ~ ........... ___ ....... __ . 87 

Profile of left valve, viewed from rear, showing great convexity. (M. P.) 

FIG. 4. Pecten (Plagioctenium) eldridgei n. sp. U. S. ~- M. 164850. Ootype ... _ ..... _ ...... _ _ 87 

Exterior of right valve (

1

anterior ear slightly broken); altitude 17 mm. Same locality as 

fig. 3. (M. P.) 

FIG. 4a. Same specimen as fig. 4 . ____ ....... _ . _ . _ .. _ ..... _ . __ _ ... __ .. _ . . . . . . . . . . . . . . . . . . . . . 87 

Profile of right valve as viewed from the rear. (M. P.) 

FIG. 5. Pecten (Plagioctenium) eldridgei n. sp. U. S. N. M. 164850. Ootype ... _ .... _ .... . _... 87 

Exterior of right valve (anterior ear broken); altitude 23 mm. Same locality as fig. 3. 

(M.P.) , 

FIG. 5a. Same specimen as fig. 5 .. __ .. ___ . ____ .. __ ~ . __ .............. ___ .. -.-... _ . . . . . . . . . . . . 87 

Profile of right valve as viewed from the rear. ( M. P.) . 

FIG. 6. Pecten (Plagioclenium) eldridgei n. sp. U. S. N: M. 164850 ...................... _..... 87 

Exterior of fragment of a large valve of this species. Same locality as fig. 3. (l\1. P.) 

194 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER N.O. 47 PL. XXV 

2 

D 5 

4 

3 

MIOCENE PECTENS. 
PLATE XXVI. 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

FIG.l. Pecten (Plagioctenium) deserti Conrad. D. A ........................................ . 

Exterior of slightly worn right valve; altitude 35 mm. Miocene, Carrizo Creek district, 

San Diego County, Cal. (M. B.) 

FIG. 2. Pecten (Plagioctenium) desertiConrad. D. A ________________________________________ _ 

Exterior of ~lightly imperfect right valve; altitude 40 mm. San1.e locality as for 

fig. 1. (S.) 

FIG. 2a. Same specimen as fig. 2 .................... _ ........ _ ... _ ....................... . 

Profile of a somewhat unusually convex · right valve as viewed from the rear. (M. P.) 

FIG. 3. Pecten (Plagioctenium) deserti Conrad. D. A ....................................... . 

Exterior of a slightly imperfect ieft valve; altitude 34 mm. Same locality as for 

fig.l. (S.) 

FIG. 4. Pecten (Plagiuctenium) deserti Conrad. D. A .. _ ................................... .. 

Exterior of left valve; altitude 37 mm. Same locality as for fig. 1. (M. B.) 

FIG. 4a. Same specimen as fig. 4 ............. __ ................... _ ......... _ ............ . 

Profile of left valve as viewed from the rear. (M. P.) 

FIG. 5. Pecten ( Plagioctenium) andersoni n. sp. U. S. N. M. 164932. Type ......... _ ........ . 

Mold of interior of left valve with portion of exterior showing sculpture; altitude 

38 mm. Miocene, Zayante Creek, Santa Cruz County, Cal. (M. P.) 

FIG. 5a. Same specimen as fig. 5 ......................................... _ ............ __ .. 

Profile of left vahre as viewed from the rear. (M.P.) 

FIG. 6. Pecten (Plag1~octeniurn) andersoni n. sp. L. S. J. U. Cotype ....................... .. 

Exterior of left valve; altitude 14 mrn., X 2. Miocene, Frenchman's Tower, near 

Stanford University, Santa Clara County, Cal. (M. B.) 

FIG. 7. Pecten (Plagiocteniurn) andersoni n. sp: U. S. N. M. 164932. Cotype .......... ~ ...... 

Exterior of right valve (anterior ear broken); altitude 20 mm. Same locality as 

fig. 5. (M.P.) 

FIG. 8. Pecten ( Plagioctertiurn) andersoni .n. sp. L. S. J. U. Cotype .................... . .... . 

Mold of interior of :· jmperfect right valve, showing shape and sculpture of anterior 

ear; altitude 30 mm. Vaqueros formation (lower Miocene), Searsville road, near 

Stanford University, Santa Clara County, Cal. (l\1. B.) 

FIG. Sa. Same specimen as fig. 8 ............................. - ........................... . 

Profile of right valve as viewed from the rear. (M. P.) 

FIG. 9. Pecien ( Plagioctenium) andersoni var. barkerianus n. sp. and var. C. A. S. Type ..... . 

Imperfect mold of interior of right valve showing portion of exterior, with sculpture; 

a]titude 41 mm. Lower Miocene, Barker's ranch, Kern Coun_ty, Cal. (S.) 

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9 

MIOCENE PECTENS. 
PLATE XX\TII 

MIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

FIG. 1. Pecten (Plagiocteni.um) d·iscus Conrad. U. C------------------- ----- -------------·---

Exterior of left valve (anterior ear slightly broken); altitude 46 mm. Miocene (upper), 

'Walnut Creek, Contra Costa County, Cal. (S.) 

FIG. 1a. Same specimen as fig. 1. __ .. ________ • ________________ . ___ .. __ •.. __ ...... ___ .... _- .. 

Profile of left valve as viewed from the rear. ( M. P.) 

FIG. 2. Pecten (Plagioctenium) discus Conrad. U.S.N. M. 13335. Type------------ - --------

Copied from a drawing by Doctor McConnell of a slightly contorted cast of the exterior 

of a left valve; altitude 47 mm. Miocene, Ventura County, Cal. 

FIG. 3. Pecten (Plagioctenium) discus Conrad. L. S. J. U----·--------------------------·----

·wax cast of exterior of right valve; altitude 30 mm. Mioeene, Santa Maria, Santa 

Barbara County, Cal. ( M. P.) 

.FIG. 4. Pecten (PliJ.giocteniurn) discus Conrad. D. A---------------------------------·-------

Mold of exterior of imperfect right valve; hinge line 24 mm. Miocene, between Morro 

and Little Morro creeks, San Luis Obispo County, Cal. (M. B.) 

FIG. 5. Pecten ( Plagioctenium) pabloensis Conrad. D. A. __ . __________________ .. _ .. _____ . ____ _ 

Exterior of left valve; altitude 34 mm. San Pablo formation (upper Miocene), San Pablo 

Bay, Contra Costa County, Cal. (M. P.) 

FIG. 5a. Same specimen as fig. 5 _ . ___________ .. _____ . _________ ... __ __________ . _____ . ______ _ 

Profile of left valve as vievv·ed from the rear. (M. P.) 

FIG. 6. Pecten ( Plagiocteniurn) pabloensis Conrad. D. A. ___________ . . ____ . _____ ... _ ..... ____ _ 

Exterior of imperfect right valve; altitude 32 mm. Same locality as fig. 5. (M. P.) 

FIG. 6a. Same specimen as fig. 6 ______ .. _____ . ___ . _________ .. ____ .. ___________ . ____ . ______ . 

Profile of right valve as viewed from the rear. (M.P.) 

FIG. 7. Pecten ( Plag·ioctenium) pabloensis Conrad. D. A __________ .. __________ . ________ . ____ _ 

Exterior of right valve of a young specimen, showing prominence of ribs near umbo; 

altitude 24 mm. Same locality as :fig. 5. ( M. P.) 

FIG. 8. Pecten (Pseudamusiurn) lompicoensis n. sp. U. S. N. M. 164931. Type ..... _. ___ .. ___ _ 

Mold of exterior of right (type) and left valves and imperfect cast of exterior of right 

valve; altitude of mold of right valve, 11.5 mm., X 3. Miocene shale, head of Lompico 

Creek, Santa Cruz County, Cal. (M. B.) 

198 .. 

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86 

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U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXVII 

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MIOCENE PECTENS. 
PLATE XXVIII. 

MIOCENE AND PLIOCENE PECTENS. 

[Unless otherwise statedall figures are approximately natural size.] 

Page. 

FIG.l. Pecten (Amusium) lompor:ensisn. sp. C. A. S. Type-------------------------·------ 92 

Mold of interior of left valve· altitude 105 mm. Miocene, 4 miles south of Lompoc, 

Santa Barbara County, Cal. (M. B.) 

FIG. 2. Pecten (Amusium) lompocensis n. sp. U. S. N. M. 164852. Cotype. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 92 

Interior of a portion of a left valve; altitude 90 mm. Miocene (lower), Ojai Valley, 

Ventura County, Cal. (M. B.) 

FIG. 3. Pecten ( Amusium) lompocensis n. sp. C. A. S. Cotype _______ " __________ . _ _ _ _ _ _ _ _ _ _ _ _ 92 

Imperfect mold of interior of right valve; hinge line 42 mm. Same locality as fig. 1. 

(M. B.) 

FIG. 4. Pecten (Pseudamusium) pedroanus Trask. U. S. N. M. 164840 ___________________ . _ _ _ _ _ 90 

Exterior of imperfect left valve; altitude 30 mm. Lower Pliocene, Third street tunnel, 

Los Angeles, Cal. (M. B.) . 

FIG. 5. Pecten (Pseudamusium) pedroanus Trask. U; S. N. M. ·164840 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 90 

Exterior .of right val e and young left valve; altitude of former, 22 mm. 8ame locality as 

fig 4. (M. B.) 

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MIOCENE AND PLIOCENE PECTENS. 
P:LA T E XXIX. 

MIOCENE, PLIOCENE, AND , QUATERNARY PECTENS. 

[Unless ·otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten (Hinnites) giganteus Gray. U.S.N. M. 13336 ..... ------·------------·-------- 93 

Exterior of the left valve of the type of Conrad's Hinnites crassa; altitude 110 mm. 

Santa Margarita formation (upper Miocene), Santa Margarita, San Luis Obispo County, 

CaL (M. B.) 

FIG. 2. Pecten (Hinrdtes) giganteus Gray. U. S. N. M. 74166 ........... _ ........... _- ......... 93 

Exterior of right valve; altitude 70 rnm. Recent, San Diego, Cal. l:\1. B.) 

FIG. 2a. Same specimen as fig. 2 ...... -------------.----·----------------------------------- 93 

Exterior of left valve. ( M. B.) 

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U. S GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXIX 

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MIOCENE, PLIOCENE, AND QUATERNARY PECTENS. 
PI .. ATE XXX. 

PLIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately n atural size.] 

FIG. 1. Pecten (Pecten ) merriami n. sp. C. S. M. B. Type. __ . ___ .. __________ . _______ . _____ . 

Exterior of imperfect right valve; altitude 120 mm. Pliocene, Piru Creek, Ventura 

County, Cal. (M. B.) 

FIG. la. Same specimen as fig. 1. Profile of both valves as viewed from the rear. ( M. P.) ___ _ 

FIG. 2. Pecten (Pecten) merrirnni n. sp. C. S . . M. B. Cotype·-------·------·-------·----·--

Exterior of imperfect left valve, altitude 110 mm. Same locality as fig. 1. (M. B.) 

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99 

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U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXX 

PLIOCENE PECTENS. 
PLATE XXXI .. 

PLIOCENE PECTENS. 

[Unl e>~s otherwise stated all figures are approximately n atural size. The light in these two figures comes from the 

right-band side. Photographs by Ralph Arnold.] 

Page. 

FIG. 1. Pecten (Pecten) bellus Conrad. A. N. S., Phila., 960------------------------------- 95 

Exterior of right valve of Gaob's Janira bella; altitude 80 mm., X 5/4. Pliocene, 

Santa Barbara, Cal. 

FIG. la. Same specimen as fig. 1 _________________________________ . _: _ _ _ _ _ _ _ _ _ _ _ _ _ 95 

Exterior of left valve, X 5/4. 

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U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXXI 

PLIOCENE PECTENS. 
PLATE XXXII. 

PLIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten (Pecten) stearnsiiDall. U.S.N. M. 148008 ...... : ............. ________________ 100 

Exterior of right valve; altitude 87 mm. San Diego formation (Pliocene), Pacific Beach, 

San Diego County, Cal. (M. B.) 

FIG. 1a. Same specimen as fig. 1 _______________ .. ______ . ______________________ . _______ . _ _ _ _ 100 

Exterior of left valve. (M. B.) 

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U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXXII 

PLIOCENE PECTENS. 
PLATE XXXIII. 

PLIOCENE AND PLEISTOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG.l. Pecten (Pecten) vogdesi n. sp. D. A. Type__________ __ _____________________________ 100 

Exterior of imperfect right valve; altitude 68 mtn. San Pedro format!on (Pleistocene), 

San Pedro, Los Angeles County, Cal. (M. P.) 

FIG. 1a.. Same specimen as fig. 1 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 100 

Profile of right valve as viewed from the rear. (M. P.) · 

Fro. 2. Pecten (Pecten ) aubnryi n. sp. C. S.M. B. Type_________________________ _________ 94 

Exterior of imperfect right valve; altitude 46 mm. Pliocene, Puente Hills, Los Angeles 

County, Cal. (S.) 

FIG. 2a. Same specimen as fig. 2 _____ . ______ __________ __________________ . __ . _. _____ ______ . 94 

Profile of right valve as viewed from the r ear. (M. P.) 

FrG. 3. Pecten (Peete'(~) hemphilli Dall. U. S. N. M. 7943. Type. ___________________ ... _ _ _ _ 97 

Exterior of right valve; altitude 57 mm. San Diego formation (Pliocene), Pacific Beach, 

San Diego County, Cal. ( M. P.) 

FIG. 3a. Same specimen as fig. 3. ____ . _______ . ____ . ___________________ .. __ ..... _ .. __ .. ___ . 97 

Exterior of left valve. (M. P.) 

FIG. 3b. Same specimen as fig. 3 _ . ___ . ______ . ____ .. _____ . _____ . __ .... _. _ .. ___ .... ___ . ___ . ~ 97 

Profile of both valves as viewed from the rear. ( M. P.) 

FIG. 4. Ptcten (Pecten) lecontei n. sp. D. A. Type_________________________________________ 98 

Exterior of right valve; altitude 59· mm. Pliocene, Cerros Island, off Lower California. 

(M.B.) 

FrG. 4a. Same specimen as fig. 4. ______ . ____ . ____ . ______ __ ___ . _____ . _____ ... ___ . ____ .. _ _ _ _ 98 

Exterior of left valve. (M. B.) · 

FrG. 4b. Same specimen a~ fig. 4 _________________ .. ____ . ___________ . ____ .. _ ... __ . _. __ . _ _ _ _ fl8 

Profile of ooth valves as viewed from the rear. (M. P.) 

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PROFESSIONAL PAPER NO. 47 PL. XXXIII 

U.S. GEOLOGICAL SURVEY 

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) 

2 

3 

4 

PLIOCENE AND PLEISTOCENE PECTENS. 
:~ 

PLATE XXXIV. 

PLIOCENE AND PLEISTOCENE PECTENS. 

[Unl ess otherwise stated all figures are a pproximately naturnl size.] 

Page. Fra. 1. Pecten (Pecten) vogdesin. sp. C. A. S. Cotype______________________________________ 100 

Exterior of slightly imperfect left valve; altitude 74 mm. Pleistocene, Ventura County, Cal. (S.) 

Fro. 2. Pecten (Pecten) auburyin. sp. C. S.M. B. Cotype ____ _______________ _______________ 94 

Exterior of left valve; altitude 36 mm. Pliocene, Puente Hills, Los Angeles County, Ual. (S.) 

Fro. 2a. Same specimen as fig. 2 ___________________________ . ____ .. ______ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 94 

Profile of left valve as viewed from the rear. ( M. P.) 

Fro. 3. Pecten (Patinopecten) puris·imaensis n. sp. D. A. Type _________________ .____________ 105 

Exterior of somewhat imperfect left valve; altitude 123 mm. Pnrisima formation (lower 

Pliocene), north of the month of Pescadero Creek, San Mateo County, Cal. (M. B.) 

Fro. 4. Pecten (Patinopecten) tumeri n. sp. L. S. J. U. Cotype ___________________________ . _ 106 

Exterior of a portion of the disk of a left valve. Pliocene. Tomales Bay, Marin County, Cal. 

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U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXXIV 

3 

PLIOCENE AND PLEISTOCENE PECTENS. 
PLATE XXXV. 

PLIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

FIG. 1. Pecten (Patinopecten) purisimaensis n. sp. D. A. Type------------··-------·--·----

Exterior of a slightly imperfect right valve; altitude 123 mm. Purisima formation 

(lower Pliocene), north of the mouth of Pescadero Creek, San Mateo County, Cal. 

(M.B.) 

FIG. 1a . . Same specimen a~ fig. 1 .. ________ . _______ . _____ . _________ . __ .. _____ . ____________ _ 

Profile of both valves as viewed from the rear. (M. P.) 

FIG. 2. Pe<:ten '(Patinopecten) turneri n. sp. L. S. J. U. Type-----------------------------· 

Exterior of an imperfect right valve; altitude 65 mm. Pliocene, Tomales Bay, Marin 

County, Cal. (M. B.) 

FIG. 3. Pecten ( Patinopecten) turneri n. sp. L. S. J. U. Ootype ___ . _ .. _ ... _ .. __ .. _ ... _, __ .. 

Exterior of a portion of a right valve showing sculpture; altitude of fragment 48 mm. (M.B.) 

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105 

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U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXXV 

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PLIOCENE PECTENS. 
PLA_TE XXXVI. 

PLIOCENE PECTENS. 

[Uj~less otherwise stated all figures are approximately natural size.] 

Fra. 1. Pecten ( Patinopecten) healeyi n. sp. U. S. N. M. 154162. Cotype ... _ ..... -..... . . . . . 

Exterior of left valve; altitude 141 mm. San Diego formation (Pliocene), Pacific Beac , San Diego County, Cal. (M. B.) 

Fw. 1a. Same specimen as fig. 1. _________ . __________________ .. ___ .... __ .. _ . _ ..... -... _.--. _ 

Profile of left valve, as viewed from the rear. ( M. P.) 

216 

Pag-e. 

103 

103 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXXVI 

PLIOCENE PECTENS. 
PLATE XXXVII. 

PLIOCENE. PECTENS. 

[Unless otherwise stated all figures are approximately natural' size.] 

Page. FIG. 1. Pecten (Patinopecten) healeyi n. sp. U. S. N. M. 148012. Type_ .. ____ . ____ .... _ ... ___ 103 

Exterior of right valve; altitude 121 mm. San Diego formation (Pliocene), San Diego 

County, Cal. (M. P.) 

Fw.la. Same specimen as fig. 1---··---------·--· ·--'·--·-------- ·---·-- -· -- -·- -·--- - ---- 103 

Profile of right valve, as viewed from the rear. (M. P.) 

Fw. 2. Pecten ( Patinopecten) healeyi n. sp. D. A ___ . ____ ._. ________________ ._. ___ . ___ ._ ... __ 103 

Exterior of a portion of right valve; hinge line 50 mm. Purisima formation (lower 

Pliocene), near San Gregorio, San Mateo County, Cal. (M. B.) 

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U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXXVII 

PLIOCENE PECTENS. 
PL _A_TE XXXVI II. 

PLIOCENE AND QUATERNARY PECTENS. 

[Unless otherwise stated all figure~;) are approximately natural size.] 

FIG. 1. Pecten (Patinopecten) caurinus Gould. D. A __________________ . _____ . ____ . ___________ _ 

Exterior of right valve; altitude 105 mm. Pliocene, Deadman l~land, Los Angeles County, Cal. ( M. B.) 

Fw. la. Same specimen as :fig. 1 ___ ___________________ . ____ _________ __ ____ . _____ . _________ _ 

Exterior of left valve. (M. P.) 

FIG. lb. Same specimen as :fig. 1 _ . __ . ______ . ___________ ________ __ ___ ___ __ __________ ___ __ __ _ 

Profile of both valves, as seen from the rear. (M. P.) 

220 

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101 

101 

101 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XXXVIII 

PLIOCENE AND QUATERNARY PECTENS. 
PLATE XXXIX~ 

PLIOCENE AND QUATERNARY PECTENS. 

[Unless otherwise stated all figures are approximately na tura l size.] 

FIG. 1. Pecten ( Patinopecten) canrinus Gould. · U. S. N. M. 13333 .. ____ .. _ . . . _ . . ____ - _-------

Exterior of imperfeet right valve of type of Conrad's Pecten meekii; aititude 154 mm. 

Pliocene, San Raphael Hills; Santa Barbara County, CaL (M. P.) 

FIG. 2. Pecten (Pat'inopecten) caurinus Gould. A. N. S., Phila __________ . ______ . _________ --

Exterior of right valve of type of Conrad's Pecten heerrnanni; altitude 62 mm., X i-. 

Pliocene, Santa Barbara, Cal. Photograph by Ralph Arnold. ( M. B.) 

FIG. 3. Pecten (Pla.gioctndum) paucicostatu.s Carpenter. U. S. N. M. 15634b. Type ____ . ___ . -

Exterior of right valve, anterior ear broken off; altitude 32 mm. Recent, Gulf of 

California. (M. B.) 

Fw. 3a. Same specimen as fig. 3. _ .. __ .. _. _____ . ___ . _____ . ______ . __ . __ ... ___ ____ . ___ . ___ _ 

Profile of right valve as viewed from the rear. ( M. P.) 

FIG. 4. Pecten (Plagioctenium) paucicostatus Carpenter. U. S. N. M. 15634b. Ootype. ___ . ___ _ 

Exterior of left valve; altitude 35 mm. Same locality as fig. 3.. (l\f. P.) 

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101 

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137 

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4 

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PLIOCENE AND QUATERNARY PECTENS. 
PLATE XL. 

PLIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size. The light in these two figures comes from the 

right-hand side. Specimen not coated by Williams process. Photographs by Ralph Arnold.] 

FIG. 1. Pecten (Nodipecten) veatchii Gabb. U. C. Type ....................... . ........... . 

Exterior of right valve; altitude 130 mm., X H- Pliocene, Cerros Island, off Lower 

California. ( M. B. ) 

FrG. 1a. Same specimen as fig. 1 _ ..... _ .. . .. _ ... ____ . __ ... _ ..... ~ ............... -- ... . .. --

Exterior of left valve. (M.P.) 

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106 

106 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XL 

PLIOCENE PECTENS. 
PLATE XLT. 

PLIOCENE AND QUATERNARY PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page . 

. FIG. 1. Pecten ( C'hlamys) pnrmeieei ball. U. S. N. M. 154479. Type. _____ ___ ..... ______ . _ _ _ _ 119 

Copied from Doctor }1cConnell's drawing of left valve; altitude 45 mm., X 5/4. (Trans. 

Wagner Free Inst. Sci., vol. 3, pt. 5, pl. 37, fig. 14.) San Diego formation (Pliocene), 

Pacific Beach, San Diego County, Cal. 

FIG. 1a. Same specimen as fig. 1 ____ . ___ ... _ . ______________ ____ ______ . __ . _________ . _ _ _ _ _ _ _ _ 119 

Copied from Doctor McConnell's drawing showing detail of secondary sculpture highly 

magnified. (Idem., pl. 37, fig. 14a). 

FIG. 2. Pecten ( Chlamys) opuntia Dall. U. S. N. M. 101'752. Type. _____ . __________ : _____ ... _ 118 

Copied from Doctor McConnell's drawing of right valve; altitude 33 mm. (Trans. Wagn'er Free Inst. Sci., vol. 3, pt. 4, pl. 29, fig. 6.) San Diego formation (Pliocene), 

Pacific Beach, San Diego County, Cal. 

FIG. 3. Pectm ( Chlamys) bartschi n. sp. U; S. N: M. 164841. Type. __ . __ . _. _. ____ . __ . _. __ . _ _ 107 

Exterior of portion of disk; altitude 55 mm. Pliocene, Crescent City, Del Norte County, 

Cal. (M.P.) 

FIG. 4. Pecten (Chlamys) hastatus Sowerby. U.S.N. M. 13350 ~----------------------------- 108 

Exterior of left valve of Conrad's type of Pecten altiplicatus; longitude 55 inm. Pliocene, 

San Raphael Hills, Santa Barbara County, Cal. (l\L B.) 

FIG. 5. Pecten ( Chlamys) parmeleei Dall. U. S. N. M. 164842 ___________________ . _ _ _ _ _ _ _ _ _ _ _ _ 119 

Exterior of slightly imperfect right valve; altitude 70 mm. Pliocene, Crescent City, Del 

Norte County, Cal. ( M. R) 

FIG. 5a. Same specimen as fig. 5 _________________________________ . ____________ . ___ . . - _ _ _ _ _ _ _ 119 

Profile of right valve, as viewed from the rear. (M; P.) 

FIG. 6. Pecten ( Chlamys) bellilamellatus n. sp. D. A. Type _____ . ________ . ____ . ______ ... ___ ._ 108 

Exterior of right valve (anterior ear slightly broken); altitude 18 mm., X 3. San Diego 

formation (Pliocene), Pacific Beach, San Diego County, Cal. ( M. B.) 

FIG. 6a. Same specimen and valve as fig. 6, natural size. ( M. P.) ________ . __ . _____ . _ . ____ _ . _ 108 

FIG. 7. Same speeimen as fig. 6 : ___________ . ___ . __ __________ _____________ _ .. __ . _ _ _ _ _ _ _ _ _ _ _ _ 108 

Exterior of left valve, X 3. (M. B.) 

FIG.7a. Samespecimenandvalveasfig. 7, natural size. (M: P.) ____ ------- ------------- -- 108 

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3 

4 

5 

6 7 

PLIOCENE AND QUATERNARY PECTENS. 
PLATE XLII. 

PLIOCENE AND QUATERNARY PECTENS. 

[Unless otherwise stated all figures are approximately natural size. The light in these figures comes from the righthand side. Photographs by Ralph Arnold.] 

FIG. 1. Pecten (Chlamys) hastatus Sowerby. F. L. B.---------------------------------------

Exterior of right valve; altitude 59 mm. Recent, Monterey Bay, Monterey County, 

Cal. 

Page. 

108 

FIG. ia. Same specimen as fig. 1 ___ ... ____________ . ________________ . ___________ . _ _ _ _ _ _ _ _ _ _ 108 

Exterior of left valve. 

FIG. 2. Pecten (Chlamys) hastatus Sowt:>rby. F. L. B---------------------------------------- 108 

Exterior of right valve; altitude 49 mm. Same locality as fig. 1. 

FIG. 2a. Same specimen as fig. 2 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 108 

Exterior of left valve. 

FIG. 3. Pecten (PlagioctPnium) circularis Sowerby. D. A _____ ________ ·----------------------- 125 

Exterior of right valve; altitude 54 mm.; San Pedro formation (Pleistocene), San 

Pedro, Los Angeles County, Cal. 

FIG. 4. Pecten (Plagioctenium) circularis Sowerby. D. A.----------------------------------- 125 

Exterior of left valve; altitude 49 rnm. Same locality as fig. 3. 

FIG. 5. Pecten (Plagioctenium) ciretdaris Sowerby, equilateral variety. D. A................. 125 

Exterior of right valve; altitude 53 mm. Same locality as fig. 3. 

FIG. 6. Pecten (Plagioctenium) circularis Sowerby, equilateral variety. D. A ....... __ __ .. __ .. 125 

Exterior of left valve; altitude 56 mm. Same lot:ality as fig. 3. 

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PLIOCENE AND QUATERNARY PECTENS. 
P L A T E X · L I I I . 

MIOCENE, PLIOCENE, AND QUATERNARY -PECTENS. 

[Unless otherwise stated all figures are approximately. natural i!ize.] 

FIG. 1. Pecten ( Chlamys) hastatus Sower by var. navarchus Dall. L. S. J. ·u ___ ____ ____________ _ 

Exterior of right valve; altitude 56 mm. Recent, Puget Sound, Washington. (M. P.) · FIG. la. Same specimen as fig. l ____________________ . _____ . ___ _____________________________ _ 

Exterior of left valve. ( M. P. ) · 

FIG. lb. Same specimen as fig. l ___________________________________________________________ _ 

Profile of both valves as viewed from the rear. (M. P.) 

FIG. 2. Pecten ( Chlamys) hastatus Sower by var. hindsi'i Carpenter. U. S. N. M. 150220 ________ _ 

Exterior of right valve; altitude 56 mm. Recent, southeast Alaska (U. S. Fish Com~ stations 2850-2851). ( S.) 

Fm. 2a. Same specimen as fig. 2 ____________ . ___________ . _________________________________ _ 

Exterior of left valve. ( S. ) · · 

FIG. 3. Pecten ( Chlamys) hastatus Sowerby var. hericius Gould. U. 8. N. M. 3881 ___ . ________ _ 

Exterior of right valve of typical form of this variety; altitude 72 mm. Recent, Puget 

Sound, Washington. (M. P.) 

Fw. 3a. Same speci~:nen as :fig. 3 ___ . . __ .. __________ . __________________ - _- __ - _--------------

Exterior of left valve. ( M. P.) 

230 

Page. 

112 

112 

112 

111 

111 

110 

110 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XLIII 

2 

3 

MIOCENE, PLIOCENE, AND QUATERNARY PECTENS. 
PLATE XLIV. 

PLIOCENE iAND QUATERNARY PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pepten ( Chlamys) jordani Arnold. U. S. N. M. 162522. Type __ . __ . _. ____ ........ _ _ _ 114 

Exterior o£ right valve; altitude 45 mm. Pliocene, Deadman Island, near San Pedro, 

Los Angeles County, Cal. (Mem. Cal. Acad. Sci., vol. 3, pl. 12, fig. 6.) (M.P.) 

FIG. la. Same specimen as fig.l _________________________________ ·····---· · ---------------- 114 

Exterior of left valve. (Idem., pl. 12, fig. 7.) (M.P.) 

Fm. lb. Same specimen as fig. 1 . ___ ... _________ .. _________________ . _____ . _. ___ . __ . _ _ _ _ _ _ _ 114 

Profile of both valves as Yiewed from the rear. (M. P.) 

FIG. 2. Pecten ( Chlamys) hastatus Sowerby var. strategus Dall. D. A _____ . ___ . ___ ..... _...... 113 

Exterior of left valve; altitude 36 mm. Pleistocene, 'near bath house, Santa Barbara, 

Cal. 

FIG. 2a. Same specimen as fig. 2 _____ . __ . _ .... _________________________ .... ________ _ ... _ _ 113 

Profile of left valve as viewed from the rear: ( M. P.) 

FIG. 3. Pecten ( Chlamys) hastatus Sower by var. strateg·us Dall. D. A. __ . ____ ._ .... _____ ...... 113 

Exterior of small left valve; altitude 21 mm. Pleistocene, San Pedro formation, Deadman Island, near San Pedro, Los Angeles County, Cal. (M. B.) 

FIG. 4. Pecten ( Chlamys) hastatus Sower by var. strategus Dall. D. A __ ... __ .... __ ... _ ..... __ . 113 

.Exterior of right valve showing secondary sculpture; altitude 21 mm., X 3. Same 

locality as fig. 3. 

FIG. 5. Pecten (Plagioctenium) cerrosensis Gabb. U. S. N. M. 61246 ____ ....... __ .... _ ... ___ .. 123 

Copied from Doctor McConnell's drawing of the left valve of Dall's type of Pecten 

subventricosus; longitude 63 mm. (Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, pl. 29, 

fig. 8.) Pliocene or Pleistocene, Ventura County, Cal. 

FIG. 6. Pecten (Plagiocten-iurn) circulctris Sowerby. F. L. B---------------····---------------- 125 

Exterior of right valve; altitude 45 mm. Recent, Gulf of California. (M. B.) (Photographed without coating by the Williams process. ) 

FIG. 6a. Same specimen as fig. 6 .. __________________ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 

Exterior of left valve. (M. B.) (No coating.) 

FIG. 6b. Same specimen as fig. 6 .... _ .................... _ .. · .......... ____ . _____ . _ _ _ _ _ _ _ _ _ 125 

Profile of both valves as viewed from the rear, showing great convexity of the typical 

form of this species. (M. P.) 

FIG. 7. Pecten (Plagiocten·ium) circular·is Sowerby. U. S. N. M. 61246. ___ . _________ . _. __ . __ .. 125 

Copied from Doctor McConnell's drawing of the type (right valve) of Dall's Pecten 

compactus; longitude 26 mm., X 7/5. (Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, pl. 

34, fig. 5.) Pleistocene or Pliocene, Ventura County, Cal. 

FIG. 8. Pecten ( Propeamusium) riversi n. Rp. D. A. Type ____ . _. _. ________ .. _. ____ ... _ . . . . 12() 

Interior of right valve, showing short internal lirre ; altitude 17 mm. Pliocene, Santa 

Monica Canyon, Los Angeles County, Cal. (S.) 

FIG. 9. Pecten (Propearnusium) riversi n. sp. D. A. Cotype ................. ___ ....... . ... _ 126 

Exterior of imperfect left valve; longitude 15 mm. Same locality as fig. 8. (S.) 

232 

, 
U. S. GEOLOGICAL SURVEY 

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PLIOCENE AND QUATERNARY PECTENS. 

PROFESSIONAL PAPER NO. 47 PL. XLIV 

l 

4 

6 

7 
PL-L~TE XL~r 

PLIOCENE AND QUATERNARY PECTENS. 

[Unl ess otherwise stated all figures are approximately natural size.] 

Pag-e. 

FrG-.1. Pecten (Chlamys) ililandicusMtiller. D. A------------------------------------------- 113 

Exterior of right valve; altitude 83 mm. Recent, Banks of Newfoundland. (M. B.) 

FIG. 1a. Same specimen as fig. 1_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 113 

Exterior of left valve. ( M. B. ) 

FIG. 2. Peden ( Chlamys) washburnei n. sp. U. S. N. M. 164843. Type.______________________ 119 

Exterior of imperfect left valve; altitude 108 mm. Pliocene, mouth of Yachates River, 

Lincoln County, Oreg. (M. B.) 

FIG. 3. Pecten (':'hlamys) lawsonin. sp. C. A. S. Type_____________________________________ 117 

Exterior of right valve (umbo and ears missing); longitude 65 mm. Pliocene, 4miles south 

of Guadalupe, Santa Barbara County, Cal. (S.) 

FIG. 4. Pecten ( Chlamys) lawsoni n. sp. C. A. S. Cotype _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 117 

Exterior of an imperfect left valve in which the umbonal region has been partially 

restored with plaster; longitude 34 mm. Same locality as fig. 3. (M. B.) 

234 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XLV 

4 

PLIOCENE AND QUATERNARY PECTENS. 
PI .. A TE XI .. VI. 

PLIOCENE AND QUATERNARY PECTENS. 

(Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten \Pecten) excavatus Anton. L. S. J. U _______________________ . ____ ... __ ... _ _ _ _ _ 134 

Exterior of right valve; altitude 65 mm. Recent, Gulf of California. (M. B.) 

FIG. la. Same specimen as fig. 1 _________ .. _______________ . _ . _ . ________ ......... __ ... __ ... 134 

Exterior of left valve; altitude 57 mm. (M. P.) 

FIG. lb. Same specimen as fig. 1 . _______ .. _ ............ __ . _ .. _____ . _ ............ _ .... _ _ _ _ _ 134 

Profile of both valves as viewed from the rear. (M. P.) 

FIG. 2. Pecten ( Chlamys) latiauritus Conrad. D. A ....... ___ .. _ . ____ .... _ ..... _. __ .. _ .. ____ . 115 

Exterior of right valve; altitude 25 mm. San Pedro formation (Pleistocene), San Pedro, 

Los Angeles County, Cal. (M. P.) 

FIG. 2a. Same specimen as fig. 2 ___ .... . _____ . ______ . __ . __ .. _ . . ___ .... _ .... ____ . _. _ .. __ . _ . 115 

Profile of right valve as viewed from the rear, showing convexity of typical form. 

FIG. 3. Pecten ( Chlamys) latiauritus Conrad. D. A _. __ ...... ____ ........................... _ 115 

Exterior of left valve; altitude 27 mm. Same locality as fig. 2. (M. B.) 

FIG. 3a. Same specimen as fig. 3 _ .. _ . _. ___ . ____ ...... _ .. __ ... _ ... _ .. _. __ .. _ .. ___ .. _ _ _ _ _ _ _ _ 115 

Profile of left valve as viewed from the rear. (M. P.) 

FIG. 4. Pecten ( Chlamys) latiauritus Conrad var. monot·irneris Conrad. D. A _. ______ . __ .. _ _ _ _ _ 131 

Exterior of right valve; altitude 20 mm. San Pedro formation (Pleistocene), Los 

Cerritos, Los Angeles County, Cal. (M. P.) 

FIG. 5. Pecten ( Chlamys) latiauritus Conrad var. rnonotimeris Conrad. D. A ... _ ... ____ ... _.... 131 

Exterior of left valve; altitude 22 mm. Same locality as fig. 4. (M. P.) 

FIG. 5a. Same specimens as figs. 4 and 5 ... _ .. ___ . _____ . ___ . __ .... ___ .. _. _ .... ____ . _. _____ . 131 

Profile of both valves, as viewed from the rear. Note the greater convexity of the left 

valve as compared with the greater convexity of the right valve in Pectens. s. (M. P.) 

Fro. 6. Pecten ( Chlamys) latiauritus Conrad var. cerritensis n. var. D. A. Type ............ _. 129 

Exterior of right valve; altitude 24 mm. San Pedro formation (Pleistocene), San Pedro, 

Los Angeles County, Cal. (M. B.) 

Fro. 7. Pecten ( Chlamys) latiauritus Conrad var. cerritensis n. var. D. A. Co type .. _._ .. _____ . 129 

Exterior of left valve; altitude 21 mm. Same locality as fig. 6. ( M. P.) 

Fro. 8. Pecten ( Chlarnys) latiauritus Conrad var. fucicolus Dall. U. S. N. M. 96049 .. ___ . __ ... _ 131 

Exterior of right valve; altitude 30 mm. Recent, on kelp, off Cerros Island, Lower 

California. (M. P.) 

FIG. Sa. Same specimen as fig. 8 _________________ .. ____ . _ .... ____ ... _. _. _. __ .. _. __ .. __ .. _. 131 

Exterior of left valve. (M. P.) 

Fro. 9. Pecten ( Chlamys) latiauritns Conrad var. delosi n. var. D. A. Type . _. __ .. _ ... _. _ _ _ _ 130 

Exterior of right valve; altitude 12 mm., X 3. San Pedro formation (lower portion), 

Pleistocene, Deadman Island, near San Pedro, Los Angeles County, Cal. (S.) 

FIG. 9a. Same specimen as fig. 9, natural size _________ ... _____ ... __ . __ . ____ .......... _._._. 130 

FIG. 10. Pecten ( Chlarnys) latiauritus Conrad var. delosi n. var . . D. A. Cotype. ____ ..... _ .. _ _ 130 

Exterior of left valve; altitude 11 mm., X 3. Rame locality as fig. 9. (S.) 

FIG. lOa. Same specimen as fig. 10, natural size ---- -------- ---- ------ -----. ---------------- 130 

236 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XLVI 

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4 

5 

7 6 

8 

10 ga 9 

PLIOCENE AND QUATERNARY PECTENS. 
PLATE XLVII. 

PLIOCENE PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten (Lyropeclen) ashley'in. sp. U. C. Type·------------------------------------· 122 

Exterior of right valve; altitude 155 mm. 

Pliocene, Cerros Island, off Lower California. (H.) 

FIG. 1a. Same specimen as iig. L .... ____ .. _________ ~ _______ . _______ .. _. ____ . ___ . _____ • _. _ _ _ 122 

Outline of both valves as viewed from the rear. (M. P.) 

238 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XLVII 

PLIOCENE PECTENS. 
PLATE xr__.vrrr. 

PLIOCENE AND RECENT PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten (Lyropecten) ashleyi n. sp. U. C. Type .... --------------------------·------ 122 

Exterior of left valve; altitude 155 mm. Pliocene, Cerros Island, off Lower California. 

(H.) 

FIG. 2. Pecten (Pseudamusium) randolphi Dall. U.S.N. M. 107749__________________________ 138 

Exterior of right valve; altitude 29 mm. Recent, off Destruction IsJand, Wash., 516 

fathoms. (U. S. Fish Com. station 3343.) (M. P.) 

FIG. 2a. Same specimen as fig. 2 _______________________________________________________ . _ _ _ 138 

Exterior of left valve. ( M. P.) 

FIG. 3. Pecten ( Pseudamusium) randolphi Dall var. tillamookensis n. var. U. S. N. M. 150233. 

Type ____________________ . __ . _____________________________________ . __ •••.. _______ . _ 139 

Exterior of right valve; altitude 30 mm. Recent, off Tillamook, Oreg., 786 fathoms. 

(U. S. Fish Com. station 3346.) (M. P.) 

FIG. 3a. Same specimen as fig. 3. ______________________________________________ .• __ . _ _ _ _ _ _ _ 139 

Exterior of left valve; altitude 31 mm. (M. B.) 

240 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XLVIII 

2 

3 

PLIOCENE AND RECENT PECTENS. 
PLATE XLIX. 

PLIOCENE PECTENS. 

(Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten ( Plagioctenium) cerrosensis Gab b. U. C _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 123 

Exterior of right valve (anterior ear somewhat imperfect); altitude 106 mm. Pliocene, 

Cerros Island, off Lower California. (S.) 

FIG. I a. Same specimen as fig. l ________________________________________________ . _ _ _ _ _ _ _ _ _ _ 123 

Exterior of left valve (anterior ear slightly broken). (S.) 

FIG. lb. Same specimen as fig. 1 _____________ ________________________________ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ 123 

Profile of both valves as viewed from the rear. 

FIG. 2. Pecten (Plagioctenium) cooperi n. sp. D. A. Type----------------------------------- 124 

Exterior of right valve (anterior ear somewhat imperfect); altitude 35 mm. San Diego 

formation (Pliocene), Pacific Beach, San Diego County, Cal. (M. B.) 

FIG. 3. Pecten (Plag.ioclenium) cooperin. sp. D. A. Cotype_________________________________ 124 

Exterior of right valve; altitude 30 mm. Same locality as fig. 2. ( M. B.) 

FIG. 4. Pecten (Plagioctenium) cooperin. sp. D. A. Type---------·------------------------- 124 

Exterior of left valve; altitude 27 mm. Same locality as fig. 2. (M. B.) 

242 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. XLIX 

2 

PLIOCENE PECTENS. 
PLATE L. 

QUATERNARY PECTENS. 

lUnless otherwise stated all figures are approximately natural size.] 

Page. 

FIG. 1. Pecten ( Plagioctenium) circularis Sowerby var. a;,quisulcatus Carpenter. U. S. N. M. 

172703.--------. ----.--.-.--- - -- .. --- . -.--------.---- .. -- ..... -.-- -------- . ------- 132 

Exterior of right valve; altitude 82 mm. Recent, San Pedro, Los Angeles County, 

Cal. (Photographed without coating to show coloration~) (M. B.) 

FIG. la. Same specimen as fig. 1. ___ . _ .. _ .. __ . _ ... _ .. __ . ____ . __ . ___ .. ____ . ____________ . _ _ _ 132 

Exterior of left valve. (Photographed without coating.) (M. B.) 

FIG. lb. Same specimen as fig. 1 .. _ .... ____ . _ . _ . _. ______ .. _. ____ .... ____ . __ . _ .. _____ . ___ . _ 132 

Profile of both valves as viewed from the rear. (M. P.) 

FIG. 2. Pecten (.JEquipecten) palmeri Dall. U. S. N. M. 150980. Ootype. ____________ . __ . . ___ 136 

Exterior of right valve (young); altitude 26 mm. Recent, head of Gulf of California. 

(M.P.) 

FIG. 2a. Same specimen as fig. 2 ____ . _ .. _ . _ .. ____ .. ________ . _______ . __ ·- ________ . _ _ _ _ _ _ _ _ _ _ 136 

Profile of right valve, as viewed from the rear. (M. P.) 

FIG. 3. Pecten (Equipecten) palmeri Dall. U. S. N. M. 150980. Type _____ . _____ . ____ . ____ . 136 

Exterior of left valve; altitude 48 rom. Same locality as fig. 2. (M. P.) 

FIG. 3a. Same specimen as fig. 3 ___ . ___ . ____________ . __________ . _ . _____ . ________ . _ . _ . _ _ _ _ 136 

Profile of left valve as viewed from the rear. (M. P.) 

FIG. 4. Pecten (Pseudamusium) davidsoni Dall. U. S. N. M. 107747. Type. _____ .. _ .. _.-.--. 138 

Copied from Doctor McConnell's drawing of the right valve of the type; altitude 14.7 

rom. (Proc. U. S. Nat. Mus., vol. 24, pl. 40, fig. 6.) Recent, Davidson Banks, 

north of Unalaska, 351 fathoms (U. S. Fish Com. Station 3330). 

FIG. 4a. Same specimen as fig. 4 .. _. ___ .... ____________ . __ . _____________ ~ _________ . _. _ . . . 138 

Copied from drawing of left valve. (Idem, pl. 40, fig. 5.) 

244 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. L 

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2 

3 

QUATERNARY PECTEN& 
PLATE LI. 

QUATERNARY PECTENS. 

[Unless otherwise stated all figures are approximately natural size.] 

Page. 

FIG.l. Pecten (Pecten) diegensis Dall. U.S.N. M.l50980. Type____________________________ 127 

Exterior of right valve; altitude 86 mm. Recent, San Pedro, Los Angeles County, 

Cal., dredged. (M. P.) 

FIG-. 1a. Same specimen as fig. 1 ________ ... _. _________________ ~ ______ __ _____ . ____ .. __ ... _ _ 127 

Exterior of left yalYe. (M. P.) 

FIG. lb. Same specimen as fig. 1 ____ . _ . ____ .. ___ ~ ________________ . __ . _____ . ___ .. __ . _ .. _ _ _ _ 127 

Profile of both valves as viewed from the rear. (M. P.) 

246 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. Ll 

QUATERNARY PECTEN& 
PLA·TE LII. 

QUATERNARY PECTENS. 

lUnless otherwise stated all figures are approximately natural size.] 

Page. 

Fro. 1. Pecten (Nodipecten) subnodosus Sowerby. L. S. J. U ...... .... ..... . ...... ... . ...... 128 

Exterior of right valve; altitude 112 mm. Recent, west coast of Mexico. (M. B.) 

FIG. 2. Pecten ( Chlamys) hastatu8 Sowerby var. albidus DalJ, U. S. N. M. 150207. Type..... 136 

Exterior of right valve, showing broad fasciculi; altitude 45 mm. Recent, Iliukliuk 

Harbor, Unalaska, 68 fathoms (U. S. Fish Com. station 3313). (M. P.) 

FIG. 2a. Same specimen as fig~ 2. _ .......... __ ................. __ . . . . . . . . . . . . . . . . . . . . . . . . . 136 

Exterior of left valve, showing narrow fasciculi. (M. P.) 

Fw. 3. Pecten (Pseudamnsium) vancouverensis Whiteaves. Type .... ... .... . . ... .... ~ ... _... 140 

Copied from original drawing of right yalve of type; altitude 8 mm., X 4. (Ottawa 

Naturalist, vol. 7, pl. 1, figs. 1 and 1a.) 

Recent, off Vancouver Island, British Columbia. 

FIG. 3a. Same specimen as fig. 3 ......................... ____ . __ .. _______ . _. _. ___ . ___ . ___ . 140 

Copied from drawing of left valve of type. 

248 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. Lll 

QUATERNARY PECTENS. 

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER NO. 47 PL. Llll 

3 2 

QUATERNARY PECTENS. 
INDEX. 

[Names in italic are synonyms; figures in black-face type are of pages giving descriptions; figures in italic show locavon 

of illustrations.] 

A. Page. 

Acila castrensis Hinds .. .. . . .. . .... .. _. . . . . . . . . . . . . . . . . 34 

Acml£a depicta Gould .. ..... . .... ..... .... .. . .... ... _ . 34 

insessa Hinds .......... ...... .... .. ... ..... . ...... . 31, 34 

instabilis Gould . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

mitra Eschscholtz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

paleacea Gould . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

pelta Eschscholtz.......................... . . . . . . . . 34 

spectrum (Nuttall) Reeve......................... 34 

tejonensis Gab b ....................... ,............ 14 

sp ......... . ........... .......... ... ... .. 19, 24, 03,117,120 

Act!eon lawsoni Weaver............................... 12 

punctoccelata Carpenter........................... 34 

traskii Stearns ........ . _ .. .... _ ....... _............ 34 

sp .................................................. 17,19 

Acus simplex Carpenter ............. _................. 36 

Admete gradlior Carpenter _ .. .. . . .. ..... , .... _____ ... 27,34 

JEquipecten Fischer .... .. ........ . . ___ ....... _. _ ..... 41,49 

opercularis Linne ........ __ . ..... ___ ............... 49 

palmeri ....... -.......... _ ... .......... 39, 49, 136-137, 244 

JEsopus chrysalloidea Carpenter . . . . . . . . . . . . . . . . . . . . . . 35 

oldroydi Arnold ... _... ............ ............ . ... 35 

Agasoma barkerianum Cooper ............... 19, 73, 78,83-84 

gravida Gabb ...... . .... __ ... __ ................. 19, 78,83 

kerniannm Cooper ...... _ ................. 19, 73, 78, 83,84 

Alaska, pectens of ................... 112-114, 134, 136,138-140 

Aligena cerritensis Arnold ... _ .. _ ....... _ .. _: . .. ....... 33 

Amalthea antiquata Linne ........................ __ .. 34 

cranioides Carpenter ................... _ ..... _.... 34 

tum ens Carpenter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

Amauropsis alocata Gabb ...... _ ..... _ .. _. _. . ...... ... . 14 

Amiantis callosa Conrad ....... __ ....... __ ............. 33 

Amphissa corrugata Reeve . _ .... _. _. _ .. , .............. 31,34 

ventricosa Arnold ....... ___ ............... __ ...... 34 

versicolor Dall..................................... 34 

Ampullina striata Gabb . _ . .......... ......... . __ ...... 12 

Amusium Bolten ...... _ .............................. _ 41 , 50 

cau1·imtm Gould ..... ... ............. _............. 101 

lorripocensis ....... · .................. 38, 50, 73,92-93,200 

mortoni Ravenel ....... ... .. . ..... .. ........ _..... 92 

pleuronectes Linne ........ _ .... .. ... _ ............ _ 50 

Anachis minima Arnold ... _........................... 35 

Ancilla californica Cooper ................ _... . ........ 14 

elongata Gabb ..... _ ......... _..................... 14 

Angulus buttoni Dall ................................. _ 19, 33 

sp ...... . .. . ....... _ .. _ .... _ ...... _ . . . . . . . . . . . . . . . . . 55, 58 

Anomia lampe Gray................................... 33 

subcostata Conrad ....... _ .................. _.. .. .. 22 

Anthozoa. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 14, 22, 30, 33 

Arago formation, equivalents of . . . . . . . . . •• . . . . . . . . . . . 10 

17260-No. 47-06-17 

Page. 

Area biloba Weaver................................... 12 

canalis Conrad ........................... 19, 24, 27, 65,76 

horni Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

labiata Sower by ........................... -....... 33 

microdonta Conrad ....... _ . ..... . ... _. __ . ... 19, 24, 78,83 

montereyana Osmont ... ... _ ..... ................. . 21,56 

multicostata .. _ ... ........ _ .... · . ..... .. ... . 91, 95,116,123 

trilineata Conrad ..... . ... .... ... _ ... . _ .... 27, 30,100,122 

sp ... _ ................ __ ..... . _ ... _ .. __ 17, 22, 51, 70, 86,117 

Architectonica cognata Gabb ... .. ..... . ....... --..... 14 

horni Gabb ············· ·-·· ····· · · ·- ···· ·······-·- 14 

tuberculata Weaver ........................... ;... 12 

Arnold, Delos and Ralph, on stratigraphy of California......................................... 32 

Ashley, G. H., on Purisima formation ... ...... ..... .. 25,30 

Assistance, those rendering, acknowledgments to..... 8 

Astarte branneri Arnold _.,. _. ...... .... ........ . . . . . . 33 

semidentata Cooper .... _............... .. . . . . . . . . . 14 

sp. _ .. _ ........... · .... . . ..... ... . _ .... _ . .. ___ . . 91, 116, 123 

Asterias remondi Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

Astoria sandstone, equivalents of .... .. .... .. -........ 10 

Astoria shales, equivalents of ...... ! ... :. . . . . . . . . . . . . . 10 

Astrodapsis tumid us Remand .... · .. ... .. . ...... 22-24, 64, 111 

whitneyi Remand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

sp ........ .... . .. .................... .. .. · .. .-........ 23,27 

Astyris californiana Gaskoin . . .. ...... .. .............. 27,35 

gausapata Gould ............................ : .. 27,30,35 

carinata Hinds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

richthofeni Gabb .............................. 27, 30,103 

tuberosa Carpenter ...... ... .... .. . . ... ............ 19,35 

sp. _ .......................................... 17, 24, 58,95 

Aturia beds, equivalents of...... . .................... 10 

Aturia. ziczac Sowerby ....................... ....... 17,58-59 

Axinea cor Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

sagittata Gabb..................................... 14 

B. 

Balanus estrellanus Conrad._ . ............ 19, 24, 28; 64, 79, 83 

sp ............ _ ...... _ ........................... 70, 73,93 

Barbatia morsei Gabb . . . .. . . . . . . .. .. . . . . . . . .. . . . . . . . . . 14 

sp.................................................. 52 

Bean Point, rocks near .................... ---........ - 15 

Bela clathrata Gabb ................. . ..... . ........... 14, 17 

fidicula Gould ..................................... 31,34 

sanct~£-monic!£ Arnold ................. -..... . .... 34 

Bibliography ........... . _ .. .. ...... . ....•.... . ...... 142-146 

Bittium asperum Gabb ..... . .. . .......... 24, 27, 30, 31, 34,117 

californicum Dall and Bartsch . . . . . . . . . . . . . . . . . . . . 34 

filosum Gould ............................... c ••• ~ · 33, 40 

253 
254 INDEX. 

Page. 

Bittium longissimum Cooper .. ·........... . .. .. . . ...... 14 

quadrifilatum Carpenter ...... . .. . ....... . . . .. -. .. . 34 

rugatui:n Carpenter................. .... .... . . .. .. . 34 

williamsoni Arnold .. ... . . . . . .. . ........ . . : . ...... . 

Blake, W. P., on Monterey shale .... . . .... .. .. . . . . ... ·. 20 

Boreotrophon cerritensis Arnold .. ... ... : . . .. . . . :_. . . . . 36 

gracilis Perry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 36 

multicostatus Eschscholtz .. . .... . .... . .. . . . ...... 36,103 

pacific us Dall ........ . ............. :. . . . ... . . . . . . . . . 27, 37 

pedroanus Arnold...... . ... .. . . . .. ... . . . . .. . . . .. . . 36 

triangulatus Carpenter . .. . ......... .. ... -.. .. .. , ... 37 

Bornia retifera Dall .... .... .. . .. ...... . ... : . . . . . . . . . . . . 33 

Borsonia bartschi Arnold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

dalli Arnold ..... ........ ·.·· · __ __ _ : ...... .. .. . ...... 36 

I hooveri Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Boulder Creek, Cal., rocks near . . . . . . . . . . . . . . . . . . . . . . . 16 

~rachiopoda~ ........................ · ...... 12, 17, 19,27,'28, 30 

-, ;Brachysphingus liratus G.abb ..................... . .... 12,14 

sinuatusGabb ----------- ---······················ 14 

British Columbia, pectens of. ... . ; . . . ............... . 109, 114 

Buccihum sp ..... ... ......... ... ........ . . 27, 91, 116,120,123 

Bulla horni Gabb . ............. -.......... .. ... . ........ 14 

punctulata A. Adams .............. .. . .. .. . . , . . .... 34, 95 

quoyi Gray ...... .... . . . ........... . .. . . . ..... ;.... 34 

Bullia striata Gabb .... ....... .. .. .. ... ........ ........ 14 

Bullinula subglobosa ,Weaver . ..................... .. . 12 

c. 

Cadulus fusiformis Sharp and Pilsbry .. ... .. . . '. ....... 34 

Crecum californicum .Dall . . .•... : .. .. . . . . . . . . . . . . ... . . 34 

crebricinctum Carpenter . . . .. ......... ~.......... . 35 

magnum Stearns .. · ..... .... ....................... · 35 

California, formatiQns in .. ·.. . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

fossil localities in ......... , .. 11, 13; 16, 18, 20-22, 26; 29, 32 

fossils from ............. 51,53-57,60-62,64, 67.:..133, 139,141 

map of, showing fossil localities................... 7 

post-Cretaceous correlation table of . . . . . . . . . . . . . . . 9-'10 

post-Cretaceous geologic column in... . . . . . . . . . . . . 9 

figure showing .... .. .... . .... ···'· .... .... .... 9 

Calliostoma annulatum Martyn ... .. ·.................. 35 

canaliculatum Martyn •............... . ~ ........ ... 31,35 

costatum Martyn .... ........... . .. .. ..... . . . ...... 35,95 

gemm ulatum Carpenter . . . . . . . . . . . . . . . . . . . . . . . . . . 35, 117 

tricolor Gabb ...... . ....... .. ... ~ ..... . ......... .. . 31,35 

sp ...................... . . . ..... ....... ~. 19, 24, 27, 118, 120 

Callista angustifrons Conrad . . . . . . . . . . . . . . . . . . . . . . . 17, 21, 27 

newcombianaGabb........ .. ... .......... ......... 33 

· sp . ......... , ............... . .. . ......... . .... 17,52,55,83 

· Callistata subdiaphana .Carpenter . ; ~. . . . . . . . . . . . . . . . . 33, 103 

· Calyptrophorus sp ....... :. .. . . . . . .. . . . . . . . .. . . . . .... . 52 

Cancellaria cooperi Gabb.......... . ......... . ......... 35 

era wfordiana Dall . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 35 

irelaniana Cooper. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

tritonideaGabb ..... ............ -................... . 35 

-1 vetusta; Gabb .. , . ............ ................. . 84 

sp . •. ................................... . ........ . .. 84,95 

Cancer sp .. _........ .... .. ... .. ... . . . . . . . . . .• . . .. . . . . ... 12 

Cardita subquadrata Carpenter. .. .... . ..... . .......... 33 

sp ............ .... . . . ...... ·......... . . ............ 85 

Carditamera subquadrata Carpenter....... . .. .. ........ 33 

sp ....................... ... .. ...•. . ........... : .... 85 

Cardium breweriGabb .... . . . ... . .............. .. . . 14,17,51 

cooperi Gabb .............. . .. . . . ............... 12, 14,55 

corbisMartyn . ........ . .. .. .. .. .. . ..... , .... 30, 33, 95,104 

elatum Sowerby .... . . . · ....... ... . :: ....... :... .... 33 

·IinteumConrad .......... . . · .. . . . .... ;.............. 14 

meekianumGabb ......... . ......... . . . ......... 24,27,30 

procerumSowerby ........... ·. ....... ... ...... ..••. 33 

Page. 

Cardium quadrigenarium Conrad ..... ~2, 23, 24, 30, 33, 95, 121 

sp ........ . .. . ......... . .............. . .... . . . 17,19,52,79 

Carrizo Creek beds, equivalents of..... ... ....... . .... . 10 

fauna of. ....... . ........ . ... . ........... . ... . .. . ... 21-22 

Caryophyllia arnoldi Vaughan...... . .... . .. . .. . ...... 33 

californica Vaughan...... . ...... .. .... .. . . ........ 30 

pedroensis Vaughan __ ........ . ... . . .. .. . .... . .... . 

Cassis sp . ................ . ... ....... .. .. . .. . ... .. ..... . 

Catalina Miocene, equivalents of. .................... . 

Cephalopoda .............. . ...... , _ .... . ... . ....... .. :. 

Cerithidea californica Haldemann . .......... ... .. . .. . 

Cerithiopsis alternata Gab b .. · . . ..... .. . . . . .......... .. . 

Cerostoma monoceros Sower by ... . ............... , ... . 

Chama exogyra Conrad .......... . ... . ... . ............ . 

pellucida Sowerby ... . .. . .... · .. . ............ . . . ... . 

Chico formation, equivalents of. . ........ . .. . ........ . 

occurrence of. . ...................... .. ........... . 

. Chicoreus leeanus Dftll- . ....... . .. . .... . ... : . . . . . . . .. . 

Chione fluctifraga Sowerby .... . ........ .. . . . . ... .. . . . . 

gnidia Broderip and Sowerby ... . ... . .. . ....... 27, 34,8 

mathewsonii Gabb ... ... . .. .... . ... . . . .... 19, 21, 55, 67, 7g 

neglecta Sowerby: ............. . ....... .......... : . s4 

simillima Sower by ... . ..... . ...... . .. . . . ;·_. . . . . . . . . 31, 34 

succincta Valenciennes .............. . ..... 19, 30, 34,104 

sp ..... . ... . . 19, 24, 27, 55, 64,66-67, 70,73, 76, 79, 83, 85, 93,95 

Chlamys Bolten ...... . .............. .41, 46-47, 49, 55, 66, 81, 94 

'bartschi ... . ... . ... . ... . ..... . . ... . 26, 37, 49, 107-108,226 

bellilamellatus ................... 26, 28, 29, 37, 49, 108,226 

branneri . . .............. . ... 16, 19, 37, 49, 55, 50--56,83, 150 

calkinsi ................ . . . ........... 14, ?7, 49, 51, 52,1.48 

discus Conrad... . ........... . ............ ........ .. 86 

fucanus Dall. .................. 19, 21 , 23, 38, 49, 66-67, 164 

hamlini .... : ........................ 19, 38,49, 67 ,·122, 166 

hastatus Sowerby .......... . ...... . .... : . .......... 26-29, 

31,33-34,38,49, 69, 94,108-110,112,115,117,226, .228 

var. albidus Dall ... . ........... . . . .... 38, 49, 136,2.48 

var. hericius Gould ..... . ; .. ... ........... .. .. 23-24, 

26---29,31,33-34,38,49,70,109, 110-111,112,115,230 

var. hindsii Carpenter............... . ......... 26, 

29, 31, 33, 38, 49,111-112,115, 230 

var.navarchusDall .......... :-................. 26, 

28-29,33, 38; 49, 112-113,115,118,-230 

var. strategus Dall.. . . . . . . 26, 29, 33-34, 38, 49, 118, 232 

hericeus Gould . . ......................... . ..... , . . . 110 

var. hindsii Carpenter........ . . . .......... . ... 111 

var. navarchus Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 

var. strdtegus Dall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 

hericius var. albidus Dall .. . ....... . .... . .... 1

• •• • • •• 136 

hydeiArnold .. ,., . .. ...... -............ ...... . ...... 69 

islandicus Muller................ . ... . ........ . .... 16, 

26, 29, 33, 38, 49, 52, 55,107, 112,113-114,115,120,23.4 

jordani Arnold ... : ..... . . 26, 29, 31, 34; 38, 49,114-115,232 

landesi. ............ . ............ . ·-· .. 14, 38, 49, 51-52, 148 

latiauritus Conrad .....•.............. 26-27,29-30,33-34, 

38, 47, 49, 82, 91,108,115-116,123,129,131,137,236 

var. cerritensis ............. 33-34,38,49, 129-130,236 

var. delosl. . ...... . ........ . ..... 33-34, 38, 49, 130, 236 

var. jragilis Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 

var. fucicolus Dall ............. 33, 38, 49, 130, 131,236 

var. monotimeris Conrad .... 33-34, 38, 49, 82, 131, 236 

lawsoni. ........................... 27, 33, 49, 117-118,23.4 

nutteri .. · ................ ·19, 21, 23, 27, 39, 49; 67-68,105,166 

opuntia Dall ......... 27-29,39,49,91,107,116,118,123,226 

parmeleei Dall ... 27, 29, 39,49, 68,100,108,119,120-121,226 

proavus; ................. . ........ 11-12, 39,52, 52-53,148 

sespeensis .... . ......... • ......... . ....... 19, 39, 49, 69, 160 

var. hydei ...... . .......... 19, 39, 49,69-70, 79,83,154 

washburnei ...... : . ....... , . . ..... 27, 39, 49, 119-120,23.4 
INDEX. 255 

Page. 

Chlamys wattsi. ...... 27, 39, 49,67-68,95,119, 1:&0-121, 122,166 

var. morani. ................... 27, 39, 49,121-122,16/, 

Chlorostoma aureotinctum Forbes ..... . ... _ ..... .. . . _ 35 

brunneum Philippi. ........ . .............. . ....... 31,35 

funebrale A. Adams........ .. ..................... 35 

var. subapertum Carpenter.... . .... . .......... 35 

gallina Forbes......... .. .... . ... . ........... . .... . 35 

montereyi Kiener .. ..... . ................. . ....... 31, 35 

pulligo Martyn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

viridulum var. ligulatum Menke ... .. . )........... 35 

sp .............................. . ......... . ......... 19,24 

Cholame Valley beds, equivalents of...... . . . . . . . . . . . . 10 

Chorus belcheri Hinds ......... . ............ 23, 24, 35, 76, 111 

Chrysodomus liratus Martyn ........ .. . .. .. . ........ ,. 27, 30 

rectirostris Carpeu ter.. .. . .. .. .. .. .. . .. .. .. .. .. .. .. 31, 35 

tabulatus Baird ............. . ........ .. . .. ... 27, 30, 31,35 

sp ................ . ........... . .. . .... ... ....... 27, 31,103 

Cidaris sp .. . . .. ... .. .... .. ........ . . : . .... 12, 24, 53, 55, 92, 120 

Clathurella conradiana Gab b .......................... 31,35 

Clementia subdiaphana Carpenter..... . ........ .. .... 31 

Clidiophora punctata Conrad ... .. . . _ .. . . . . . .. . . . . .. . .. 27, 33 

Clypeaster bowersi Merriam.......... . . .. .. ........... 22 

-brewerianus ...... . ... .. ........ . ..... .- . . . . . . . . . . . . 17 

gabbi Remand ...... . .. . ................... _...... 23 

sp.... .... ........ . .... .. . . . . . .. .. .... . ... . ... . ..... 57 

Coccinodiscus sp......... .. .. . .. . .. .. .... .. .. .. .. .. .. .. 20 

Codakia sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 

Columbella californiana Gaskoin... .. ......... . . . ..... :55 

chrysalloidea Carpenter.......... .. .. . .. . .. . . .. .. . 35 

gausapata Gould .......... . ........... . .... .. ...... 31, 35 

var. carinata Hinds .................... . ....... 31,35 

minima Arnold .. .. . . .. . .. . . .. . .. .. .. .. .. .. .. . . .. .. 35 

oldroydi Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

richthofeni Gabb .... . ...... .. .. . .... .. .. .. .. .. .... 117 

solidula var. pr~cursor Arnold.................... 35 

tube rosa Carpenter .. .. .. .. . .. .. .. . .. . .. . . .. . . .. .. . 35 

Colombia, pectens of................................... 126 

Contra Costa Miocene. equivalents of. . ........ . ....... 10 

occurrence of......... .. . .. .. .. .. . . .. . .. .. . . .. .. . .. 17 

Conus califomicus Hinds ............................. 31,35 

horni Gabb.. .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . .. .. 14 

remondi Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

sp ..... _ ...................................... 19,52, 84,104 

Cooper, J. G., on Eocene fossils........................ 14 

Cooperella subdiaphana Carpenter............... . .... 33 

Coos conglomerate, equivalents of . . . . . . . . . . . . . . . . . . . . 10 

Coralliophila nux Reeve........................ .. ..... 35 

Corbula al~formis Gabb............................... 14 

evansiana Shumard .. . .. . .. . .. .. . .. .. . .. . .. . . .. .. . 19 

horni Gabb ...... ..... ... .. ... . ....... ...... ....... 14 

luteola Carpenter ............................ . ..... 30, 33 

parilisGabb.......................... . ............. H 

primorsa Gabb.......... . .. . .. . ....... .. . .. .. . . .. .. 14 

sp ..................... . .. .. . ... ........ 17,21,27,52,55,56 

Cordi era gracillima Cooper.... . . . . . . . . . . . . . . . . . . . . . . . . 15 

microptygma Gabb.......................... . ..... 15 

Correlation, post-Cretaceous, table showing........... 9-10 

Crassatellites grandis Gabb............................ 14 

unioides Stanton .. .. . .. .. . . .. . .. .. .. .. .. . .. . . .. .. . 12 

uvasana Conrad...... . ........ .. ................. . 14 

sp..... . ... . ... .. ... .. . ... ................. . . ... . .. . 52 

Crassinella branneri Arnold . .......................... 33 

Crepidula aculeata Gmelin.......... . . . . . . . . . . . . . . . . . . 35' 

adunca Sowerby ................................... 24, 35 

dorsata Broderip ............. ............ ... ...... 35 

navicelloides NuttalL .................... ___ ...... 27,30 

onyx Sowerby .......... , .......................... 27, 35 

pr~rupta Conrad.................................. 17 

Page. 

Crepidula princeps Conrad ..... 19, 24, 27, 28, 30, 35, 79, 105, 117 

rugosa NuttalL .. . .................... .. ........ 27, 35, 95 

sp . ..............•... . ................. .. . .... ...... 66,95 

Crucibulum spinosum Sower by . . . . . . . . . . . . . . . . . . . . . . . 35 

sp................................ . .................. 84 

Crustacea ....... . ....... . ............ .. .... . ..... 12, 19, 24,28 

Cryptochiton stelleri Middendorf .. : . .... . ........ .. .. 31,35 

Cryptomya californica Conrad ... . ............. . 27, 30, 33,65 

Cucull~a mathewsoni Gab b........................... 12 

Cuma biplicata Gabb ... . ............ . ... .. .... .. ...... 19,79 

Cumingia californica Conrad . . . . . . . . . . . . . . . . . . . . . . . . . 30, 33 

Cylicbna alba Brown .. . ........................... :. . . 35 · 

costata Gabb .. .. .. .. .. .. .. .. .. . .. .. . .. .. . .. .. .. .. . 12 

borni Gabb ........ .... .... .... .... ........ .... .... 17 

petrosa Conrad .. . .. .. . .. . .. . .. .. .. .. .. .. .. .. . .. .. . 17, 21 

Cypr~a bayerquei Gabb .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. 15 

matbewsoni Gabb.......................... . ...... 15 

spadicea Gray........ . ........ . .. . ................ 35 

sp................. . ...................... . ......... 22 

Cyrena californica Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

Cytbara branneri Arnold.............................. 35 

Cytherea vespertina Conrad.. . . . . . . . . . . . . . . . . . . . . . . . . . 17, 55 

sp .......... . ................... . ............. 17,21,56,57 

D. 

Dall, W. H., on classification of pectens . .... . .......... 45-50 

on San Pedro formation .............. _......... ... 32 

on Tertiary horizons.................... ... .... . ... 10 

Deadman Island Pliocene, equivalents of . . . . . . . . . . . . . 10 

fauna of ................. .. .. . ......... . ... . ....... 30-31 

Dentalium cooperi Gabb ....................... 12, 15, 17,52 

indianorum Carpenter .. .. .. .. .. .. .. .. .. .. .. .. .. .. 35 

neobexagonum Sharp and Pilsbry ........... . .... 28, 95 

neobexagonum Sower by . .. . .. . .. . . .. .. . . . . .. . .. . . 35 

pseudobexagonnm Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

semipolitum Broderip and Sowerby... . . . ......... 35 

stramineum Gab b ..... . ............................ 12, 15 

substriatum Conrad ........... .. ............... 17,57-58 

sp ............................... 17, 19, 66, 73, 84,_93, 95,117 

Dentipecten circularis Sowerby.. . . . . . . . . . . . . . . . . . . . . . . . 125 

Diastoma sp . . . .. .. . .. . .. .. .. .. . .. .. .. . . . .. . .. .. . . .. . • . 35 

Diller, J. S., on Oligocene of Washington ............ , 15 

Diodus tennis Gab b..................... . ...... . ....... 15 

Diplodonta orbella Gould.............................. 33 

serricata Reeve .................................... 21,33 

sp. . ................................................ 57 

Diploria bowersi Vaughan. ................. . .......... 22 

Discohelix californicus Weaver.......... . .... . .. . . .... 12 

Dolicbotoma carpenteriana Gab b ......... . ........ 27, 36,117 

coo peri Arnold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

tryoniana Gabb ............................ . ...... 36,117 

sp ............ _.. . ..... ....................... . ...... 84 

Dolium petrosum Conrad ............... . .. . .. . ... . .... 57-58 

ringens Sower by............................. . . .. .. 22 

sp ....................... :.......................... 17 

Donax californica Conrad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

l~viga ta Desha yes.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

latus Gabb....................................... . . 14 

Dosfnia conradi Gab b ..... . . . ............ . ............. 19,79 

elevataGabb....................................... 14 

gyrata Gabb . . . . .. .. .. .. . . .. . .. . .. . .. . . . .. .. . . .. .. . 1-! 

matbewsonii Gab b .............................. 19, 79,83 

montana Conrad ................................... 19, 7g, 

ponderosa Gray ............... : ..... 19, 23, 27, 73, 79, 83, 104 

sp ....................................... . . 22, 27, 65,83-84 

Drillia cancellata Carpenter.................... . .. . . . . 35 

hemphilliStearns.... .... ....... .. ... .... ... . . ..... 35 

incisa Carpenter ................................... 27,30 
256 INDEX. 

Page. :page 

Drillia inermis Hinds..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30, 35 Fusus thracius Conrad .. _ .. . . . .. .. . .. . .. . .. . . . .. .. . .. . . 17 

var. penicillata Carpenter..................... 35 sp ..... _ .. _ ....... _ ........ _ ... _ .. 17, 19, 24, 52, 57-59, 73,93 

johnsoni Arnold ........ . ..... ... .... _ ...... _._.... 35 

merriami Arnold _ ....... _ ......................... 31, 35 G. 

montereyensis Stearns._ ........... _ .. _._ ....... _._ 35 

pudica Hinds ______ ..... __ ................ __ ....... 35 Gadinia reticulata Sower by............................ 35 

Ga1eocerdo productus Agassiz......................... 19 torosa Carpenter .. ; ......................... 31, 35, 84,117 

ullreyana Cooper ........ _. . . . . . . . . . . . . . . . . . . . . . . . . 15 Galerus excentricusGabb .................... 12,15,17,19, 79 

inornatus Gabb.................................... 27 sp.................................................. 95 mammillaris Broderip .......................... 17, 19,35 

E. Gari alata Gabb .. ....... ....... . .. .. _.................. 23 

Gasteropoda ... _ ... 12,14-15,17,19,21-22,24,27-28,30,31,34-37 

Echinarachnius excentricus Eschscholtz .... 28, 30, 33, 99,122 Gastrochrena sp. .. .. .. .. .. .. .. .. .. . .. . . .. .. . .. . .. . .. .. . 22 

sp ..................................... ........... 103,117 Glottidia liJbida Hinds ........... __ ................. , .. 27 

Echinoidea __ ..... __ ........... ___ 12, 19, 22,23-24,27,28, 30,33 Glycymeris barbarensis Conrad _ .................... :. 33 

Empire beds, equivalents of._ ....... _ .. _ .. _ ........ _.. 10 corGabb ....................... ·.,.. . ............... 14 

Enspira alveata Conrad .... _ ................... _....... 15 patulus Conrad ......... ....................... 24, 64,118 

Eocene rocks, formations of .............. _......... ... 9-15 sagittata Gabb. _ ......... , ... , .................... ·. 14 

fauna of ..................................... 11-12,14-15 septentrionalis Middendorf._...................... 33 

occurrence of. ........... _ ... ---- .. _ ... _ ...... _.... 9,10 veatchii Gabb var. major Stanton ............... _. 14 

pectens of ........ ; ................ 11,14,37-41,51-54,1t.B sp ......................... 19, 21, 23, 52, 58, 73, 79, 83, 85,118 

Epiphragmorphora sp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Glyphis densicla:thrata ......... ; ................. 91, 116, 123 

Epona mathewsoni Gabb........... ..... .......... .... 15 Gyrodes dowelli White .................... _ ...... _._.. 15 

Erato columbella Menke ........... .' ................ .. sp ................... ,............................... 73 

sp .................................................. 57-51:l 

Eulima falcata Carpenter.............................. 35 H. 

hastata Sower by .... ___ .... ................... . .... 35 Haliotis fulgens Philippi............. . . . . . . . . . . . . . . . . . 35 

'micans Carpenter ................. _................ 35 Haminea virescens Sower by .... _ ............. , . _. . . . . 35 

Eupleura muriciformis Broderip ........ __ ............ 35 Hamlin, Homer, on Vaqueros sandstone.. . ........... 18 

muriciformis var. curta Arnold. __ ._ ...... _ ... ___ ._ 35 Helcion dichotoma Gab b ........................ .. .. .. 12,53 

Helix (Epiphragmophora) sp.. ........................ 35 

F. Heteroterma gabbiStanton. ... .. . ... . . . .... . . .. . . . . .. . 12 

striata Stanton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Fairbanks, H. W., on Vaqueros sandstone ........ ___ .. 18 trochoidea Gab b . ............ _..................... 12 Fasciolaria io Gabb ........ _ .................... _______ 15 

lawiuscula Gabb. _. ________ .. _ ..... _. _ ... __ ... _... 15 

sinuata Gabb ................................. ..... 15 

sp ................................. y· ·· ··........... 12 

Hinnites Defrance ............................. _ 41, 48, 60,94 

cortezi Defrance. . .. . .. . . . . . . . . . .. .. . . .. . . . .. . .. . .. 50 Fauna, fossil, lists of. .. __ ... 12,14-15,17,19,21-24,26-31,33-37 

localities where found, lists of .. _ 11, 13, 16, 20-22, 26, 29, 32 

Favia merriami Vaughan.............................. 22 

Fic'opsis angulatus Weaver. .... _.. . . .. .. . . . . . . . .. . . . . . 12 

cooperi Gabb ....... _ ......... __ ................... . 15 

horni Gabb . .. . . .. . .. .. . . . .. . . .. . . . . . . . .. . .. . . .. . .. 15 

remondi Gabb .. .. . . . . . .. .. .. .. . .. . . .. .. . .. . .. . .. .. 15 

Fissurella volcano Reeve .............. .'............... 35 

crassa Conrad ................................. _· 93, 94, 202 

giganteus Gray ............. _ ........... _ .. _........ 19, 

21, 22, 23, 26, ,29, 33, 38, 50, 93-94, 95, 109, 202 

poulsoni Conrad ....... __ .. .. .. .. .. .. .. . .. .. .. .. . .. 93 

Hipponyx antiquatus Linne ........................... 31,34 

Hyatt, A., on law of evolution . _ ...... _............ .... 127 

Hypogella diegoensis Gabb .................... :....... 14 

Fissuridea aspera Eschscholtz ... _ ... _.................. 35 I. inrequaliR Sower by ....... _........................ 35 

murina (Carpenter) Dall .......................... 35,95 Isapis fenestrata Carpenter._ ... _ ..... _ .. __ ............ 35 

sp.................................................. 19 Ischnochiton regularis Carpenter . _ ............... _... 35 

Flabellum californicum Vaughan..................... 14 Ivara turricula (Carpenter) Dall and Bartsch......... 35 

remondianum Gabb .... _ ........................... 12,14 

Foraminifera _ .................... ___ ... .. . .. .. .. .. . . .. . 12 .J. 

nummuloid........................................ 12 Janim bella Conrad----·· .... . .. ..... __ . ____ ... ··-- .... 95-96 sp .... --------··········-· :............... ........... 12 

Fort Tejon, Cal., rocks near ................. , .. _...... 13 

Fossil localities, lists of ......... _. 11, 13, 16, 18, 20-22,' 26, 29, 32 

map showing location of........................... 7 

Fusus requilateralis Weaver ........................... ' 12 

dentata Cooper., .. _ .................... : ..... ·_ .. __ . 100 

dentata Gab b .... _............. ..................... l'oo dentata Sower by .............. _ . . . . . . . . . . . . . . . . . . 135-136 

florida _Hinds __ .................. , ........ ; .. _. . . . . . 128 

arnoldi Cossmann ................. _.. . . . . . . . . . . . . . 35 ··K· 

barbarensis Trask ........... .......... ..... 31, 35, 95, 121 

californicus Conrad .... ....... ...... ...... _ .... _ . . 15 Kellia laperousii Desha yes ... -.-_ ...... -.·. _ .. _ ..•..... _. 30,33 

diaboli Gabb .... , .. .. .. .. . .. .. .. . .. . .. .. .. . .. .. . .. 15 

luteopictus Dall ............ · .................. _.... 35 

suborbicularis Montague ............. __ ........... 33 

Kennerlia bicarinata Carpenter ..... :_ ............... 33, 103 

martinez Gab b......... . ......... ........... ....... 15 filosa Carpenter ......... . ·.. .. .. . .. . . .. . .. .. .. .. .. .. 33 

mathewsonii Gabp . ... . . . . . . . . . . . . . ... . . . . . . . . . . . . . . 17 grandispan ····--··············-··········-· ...... 103 

oregonensis C()nrad--- ... .. .. .... .. .. ...... . . .. .... 17 

robustus Trask ..... _ ................................ 24,35 L. 

rugosus Trask.. . .. . .. . .. . .. . .. .. . .. .. .. .. . . .. .. .. .. 27, 35 Lacuna compacta Carpenter ........................ 1.. 35 

supra planus Cooper ....... __ .. _ ................. __ . 15 porrecta Carpenter ... -.. ...... :................... 35 
INDEX. 257 

Page. 

Lacuna solidula (Loven) Carpenter ......... _. ........ 35 

Lrevicardium linteum Conrad ....... ____ ...... . ....... 14 

substriatum Conrad ............................... 27, 33 

sp ....................... ---- -----------············ 17 

Lamellaria stearnsii Dall. .................... : ........ 35 

Lamna clavata Agassiz................................ 19 

Laqueus californicus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 

jeffreysi Dall ................................... 28, 30,77 

Lawson, A. C., on Monterey shale .... .......... _ .... 20,26,30 

Leda alreformis Gabb .............. _... .. ......... . .... 12 

fossa Baird . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27, 33, 84 

gabbi Conrad ...................................... 12,14 

hamata Carpenter .... _........ . ...... . . . . . . . . . . . . . 33 

min uta var. prrecursor Arnold . . . . . . . . . . . . . . . . . . . . 33 

taphria Dall ................. 19, 27, 28, 30, 33,83-84,95,117 

sp ..... .. ......... . ........... . 17, 19, 21, 55,57-59,66,73,93 

Leptopecten monotimeris Conrad ................ _ . . . . . . . 131 

Leptothyra bacula Carpenter. . . . . . . . . . . . . . . . . . . . . . . . . . 35 

carpenteri Pilsbry................................ . 35 

paucicostata Dall ................................ .. 27,35 

Leucosyrinx pedroana Arnold .. . . . ................... 36, 84 

Lima dehiscens Conrad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

hamliniDall ............. .. ................... 91,116,123 

multiradiata Gab b ........ . .................. ... ... 12,14 

sp .................................................. 24, 92 

Liropecten crassecardo Conrad. . . . . . . . . . . . . . . . . . . . . . . . . . 71 

estrellanusConrad .......................... : ...... 74-75 

Heermanni Dall. ............................... 75, 79, 101 

veatchii Cooper .............................. . .. .. . 77,106 

Lithophaga plumula Hanley...... .... ......... . ...... 33 

sp...... ................. ... .... .... .... ..... ... .... 22 

Litorina planaxis Phil... . . . . . . . . . . . . . . . . . . . . . . . . 24, 30, 31, 35 

remondi Gabb ....... ................. . ..... .. ..... 24,73 

scutulataGould.... .. . . . . .. . ... . . .. ... . . . . . . . . . . ... 35 

Little Falls, Wash., formations near....... . ........... 10 

Localities, fossil, lists of. ......... 11, 13, 16, 18,20-22, 26, 29, 32 

Loxotrema turrita Gab b......................... . ..... 15 

Lucapina crenulata Sower by........... . .. . . . . . . . . . . . . 35 

Lucapinella callomargiriata Carpenter.... . . . . . . . . . . . . 35 

Lucina acutilineata Conrad .......................... 34,117 

californica Conrad ................ _·. . . . ...... ... ... 34 

cretacea Gabb .. .......................... .. ... . ... 14 

tenuisculpta Carpenter............................ 34 

Luponia bayerquei Gabb... ... . ...... ....... .. . . . . . ... 15 

Lunatia hornii Gab b ................................... 12,15 

lewisii Gould ............... ... ...... 24, 27, 30, 36,117-118 

nuciformis Gabb.. ...... ..... .. . . .. . . . .... .... ..... 15 

shumardiana Gabb ................................ 15,17 

sp ............................................ 52, 57-58, 84 

Lutraria traskii Conrad .................. · .............. 20,21 

Lyonsia californica Conrad ..................... _ ...... 31, 33 

Lyropecten Conrad ....................... 41, 46, 49, 71, 81,141 

ashleyi............................................ 26, 

28, 29, 37, 49, 72, 91, 95,116, 118,121,122-123,~38,240 

bowersi ............... . 19, 21, 37, 47, 49, 70-71,141,168,170 

crassicardo Conrad.. . . . . . . . . . . . . . . . . . . . . . . . . 19, 21, 23, 24, 

38, 49, 71-73,78,81,83, 89,92-93,122,141,176,178, 180 

var. hamiltoni ............. 19, 23, 38, 49, ';'3-74, 81,166 

diabloensis Arnold.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 

estrellanus Conrad ...................... .......... 19, 21, 

23-24,38,49,64, 67, 70,72-74, H-76 

77,79-80,102, 111, 141, 18~. 184, 186 

var. cAtalinre .............. 23,26,38,49,63, 76-71,184 

var. terminus . . . . . . . . . . . . . . . . . . . . 23, 24, 38, 49, 7 7, 190 

Hee1·manni Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75, 79, 101, 102 

magnolia Conrad. 19, 39, 49, 70-72, 7 7-79,80-81, 107,192-194 

miguelensis .................. 19, 39, 49, 79-80, 102, 188, 190 

perrini. ....................... 19, 21, 39, 49,80-81,172,174 

. Page. 

Lyropecten vaughani ................... )9, 39, 49,81-82,190 

volrejormis Conrad ..... . ....................... . 74, 75,184 

1\L 

Macoma calcarea Gmelin ................. 19, 27, 30, 31, 33, 103 

indentata...................... . ................... 33 

inquinata Desha yes ........... . .......... 27, 30, 31, 33,103 

nasuta Conrad .................. 17, 19, 23, 27, 28, 30, 33,103 

var. kelseyi Dall........................... . ... 33 

sabulosaSpngl ..................................... 30 

sectaConrad .................. ....... ... ... ........ 33,99 

yoldiformis Carpenter.......... ... ............ . . . . 33 

sp ................................... 17, 59, 91,116-117,123 

Macron kellettii A. Adams ..... . . . . . . . . . . . . . . . . . . . . . . 35 

livid us A. Adams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

Mactra californica Conrad·. . . . . . . . . 19, 23, 24, 27, 30, 33, 83, 103 

catilliformis Conrad.... . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 67 

exoletaGray................... . ................... 34 

falcata Gould ................. ... .................. 23, 24 

hemphilli Dall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27, 34 

planulata............ .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 

sp............ ........ .... ..... ...... ..... .......... 66 

Malea ringens Sower by ........................ .. ...... 22,85 

Mangilia angula ta Carpenter. . . . . . . . . . . . . . . . . . . . . . . . . . 35 

hooveri Arnold. ____ .......... _____ ... __ ........... 35 

interfossa var. pedroana Arnold ... : .............. . 

interlirata Stearns .. ... . . .. . .............. .... .... . 

oldroydi Arnold .......... _ ....... .. .............. . 

paineiArnold ............. _ ....... __ .............. . 

saturalis Cooper .................................. . 

35 

35 

35 

35 

15 

s'culpturata Dall ............... . ......... ... ....... 31, 35 

striosaC.B.Adams ........................ . .•..... - 35 

Map of California, showing fossil localities ..... ~...... 7 

Marcia subdiaphana Carpenter........................ 31 

Margarita optabilis var. knechti Arnold.............. . 35 

optabilis var. nodosus Arnold.. . . .. .. .. ............ 36 

parcipicta var. pedroana Arnold .. _. ................ 36 

pupilla Gould . . ... :................................ 30 

Margaritella crenulata Gabb ... __ . ...... . . . . . . . . . . . . . . 15 

Margin ella jewettii Carpenter. ....................... . 

sp .............................. . .................. . 

Martesia ovoides Gould ............................... . 

36 

57-58 

117 

Martinez, Cal., rocks near .. . __ ...... .. ........ __ . . . . . . . 11 

Martinez formation, character of ..... _ . . . . . . . . . . . . . . . . 11 

equivalents of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

fauna of ................... . ....................... 11-12. 

occurrence of. ...... _ ................... __ . . . . . . . . . 9, 11 

pectens of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11, 37-40 

Megatebennus bimaculatus Dall .... .. ............ . .... 19,36 

sp.......................... ........ . . ........ ...... 12 

Megistostoma striata Gabb .. ..... . _ .......... _ ........ 12,15 

Merced, Lake, rocks near ............. ___ .............. 28 

Merced formation, character of........................ 29 

equivalents of..................................... 10 

fauna of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-31 

occurrence of.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 28-29 

pectens of ....... _ ............................... 29,37-40 

Meretrix californica Conrad........................... 14 

horni Gabb ............ ___ ........... ..... ......... 14,51 

ovalisGabb........................................ 14 

uvasana Conrad ............... .. ................. . 

sp ................................................. . 

Merriam, J. C., on Contra Costa Miocene ............. . 

on Martinez formation ........................... . 

on pecten in Cretaceo:us shale .................... . 

on San Pablo formation ....... . .................. . 

on Tejon formation .............................. . 

on Vaqueros formation ......... .' ................. . 

14 

12,52 

17 

11 

54 

22,23-

14 

18 
258 INDEX. 

Page. 

Merriam, J. C., on Ventura County fossils .. ,.......... 99 

Metis alta Conrad ..................... _ ............... 28, 34 

Mexico, fossils from ............... 60-61,126,129,136-137,139 

Miocene rocks, formations of. .................... 9-10,17-24 

fauna of ..................................... 18-19,21-24 

-occurrence of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 17 

pectens of .... 18-19, 21, 23, 37-42, 56, 59-94, 111, 150-'202, 230 

Mitra cretacea Gab b ................... _____ ... _ ... _._. 15 

Page. 

Naticina obliqua Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

Nautilus sp ....... ..... ................... ..... .. .. .. . . 52 

N erera pectinata Carpenter. . . . . . . . . . . . . . . . . . . . . . . . . . . . 17, 34 

Neptunea cretacea Gab b ................... _........... 15 

· gracilis Gab b.......................... .. ........... 15 

humerosa Gabb ............................... . : ... 27 

mucronata Gab b .............. .... ... ~-............ 12 

supraplicata Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

maura Swainson .................................. . 36 sp .. . .... . ...... .. . .. .. . . ........... ... . . . . . . . . .... . 84 

simplicissima Cooper ................ _ .. ___ . _ ... .. . 15 Nerita triangulata Gabb............................ . . . 15 

Mitramorpha filosa Carpenter ........................ . 36 Neverita globosa Gab b .. .... ........... . ......... ,.. ... 15 

intermedia Arnold ............ _ .. _ ............... . 36 recluziana Petit ............ .. ......... _ ......... ·... 19, 

Modiolus fornicatus Carpenter . . . . . . . . . . . . . . . . . . . . . . . . 34 

merriami Weaver.................................. 12 

ornatus Gabb ............. _ .. _____ .......... __ .. 12, 14,51 

rectus Conrad ...... .. ...... :. . . . . . . . . . 17, 27, 28, 30, 34, 95 

sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17, 23, 69 

Moerella salmonea Carpenter ......................... 27,34 

Molopophorus striata Gab b ............... . . . ..... _.... 14 

Monia macroschisma Deshayes........................ 34 

Monoceros engonatum Conrad ........... _ ............ 30, 36 

lapilloides Conrad................... . ............. 36 

Monterey, Cal., rocks near ......... ·. . . . . . . . . . . . . . . . . . . 20 

Monterey shale, character of.......................... 20 

equivalents of..................................... 10 

fauna of . . _ .... : . .. ~ ... _ .. _. _ . ___ . _ ............. o .. 21-22 

occurrence of .................. _ ...... __ ...... _ . _ 9, 20-21 

pectens of .................. _ ..... .. .... . ....... 21, 37-40 

Mopalia ciliata Sowerby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Morio tubereulatus Gabb __ . _ .... __ ...... , ............. 12, 15 

Mulinia densata Gabb .. . . ... ..... .. . . . .. . .. . . . . . . .. . .. 23 

Murex festivus Hinds ............. ~................... 36 

foliatus Martyn.................................... 36 

leeanus Dall ................ _. _. _....... . . . . . . . . . . . 36 

monoceros Sower by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

nuttalli Conrad ............... . . _ ..... _ . . . . . . . . . . . . 36 

trialatus Sower by, ....... __ ... __ ..... _ . _ . . . . . . . . . . . 36 

sp. ............. ...... ............ ...... ............ · 52 

Myrtea?................................................ 17 

MysiapolitaGabb........................... .... . ... .. 14 

Mytilimeria nuttalli Conrad ......... . ... ... ........... 31,34 

Mytilus ascia Gabb............ .. . . . . . . . . . . . . . . . . . . . . . . 14 

californian us Conrad.......... .. .................. 30 

dichotomous Cooper....... . . . . . . . . . . . . . . . . . . . . . . . . 14 

edulis Linne ............ . .........•................ 30-34 

humerus Conrad ....... _._ .. _...................... 14 

mathewsonii Gab b .............. __ ..... 19, 27, 70, 73, 711, 86 

sp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 24, 66, 117 

Mytilus beds, equivalents of........................... 10 

N. 

Nassa antiquata Gab b...................... ............ 15 

californiana Conrad ............. , . ... _ .... __ .. _. 27, 31,36 

cerritensisArnold...... . ................ ...... ..... 36 

cretacea Gab b...................................... 15 

fossata Gould ............. _. ............. 30-31, 36, 95, 104 

insculpta Carpenter .... :. . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

mendica Gould . . . . . . . . . . . . . . . . . . ... . . . 19, 27, 30, 31, 36, 100 

var. cooperi Forbes .......................... . . 31,36 

perpinguis Hinds ..................... 27, 31, 36, 84, 95,117 

tegula Reeve ........ ·............................... 36 

versicolor var. hooveri Arnold..................... 36 

sp ...... ; . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 73, 91, 93, 99, 116, 123 

Natica clausa Broderip and Sower by ........ 27, 30, 31, 36,103 

ocoyana Conrad.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19, 83 

lewisii Gould .. ... . ........ . . . . ....... : ........... ; . 36 

. recluziana ................................ _... .. ... 95 

uvasanaGabb ..... .'................................ 15 

Sp •.•........................... 12, 17, 24,57-58,84,117,120 

22, 28, 31, 36, 79, 91, 95, 104, 116, 121, 123 

saxea Conrad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

secta Gabb ................. .. ... ·. . . . . . . . . . . . . . . . . . . 15 

sp ............... : ......... :. . . . . . . . . . . . . . . . . . . . . . . 24, 120 

Nodipecten Dall ............................ .... ....... 41, 4,9 

nodosus Linne .................................... 49,129 

subnodosus Sower by ... 33-34, 39, 49, 107, 128·129, 248, 250 

veatchii Gabb .................. 27, 39, 49, 98,106-107,224 

Norrisia norrisii Sowerby ........ ·...................... 36 

Nucula castrensis Hinds .................... ... .. 27,31, 34,65 

decisa Conrad ....... '............. ..... ~ ........... 57,66 

suprastriata Carpenter . .. .................. ;....... 34 

truncata Gabb ................... ~ ................. 12,14 

sp ............................................ 17, 55, 57,58 

Nutter, E. H., work of................................. 68 

o. 

Ocinebra barbarensis Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

cancellina Philippi.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 86 

foveolata Hinds. ............... . ................... 36 

interfossa Carpenter ............................... 31, 36 

keepi Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

lurida Mid d ........................ . ............. 19, 24, 36 

var. aspera Baird ............ ; ................. 36 

var. cancellina Philippi....................... 36 

var. cerritensis Arnold......................... 36 

var. munda Carpenter......................... 36 

micheli Ford. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 · 

perita Hinds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

poulsoni NuttalL.................................. 36 

sp ................•................................. 23,52 

Odostomia gouldii Carpenter. . . . . . . . . . . . . . . . . . . . . . . . . . 36 

nuciformis var~ avellana Carpenter.. .... ......... 36 

ten uis Carpenter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Oligocene rocks, fauna of .. · ........................... 16-17 

formations of ......................... ·. , ...... 9-10,15-17 

occurrence of.......... .. ..... .. ................... 9, 15 

pectens of. ........ . ................... 16, 37-41,54-59, 150 

Oligocene-Miocene rocks, pectens of. .............. 55, 57,59 

Olivasp ... , ...................... :..................... 22 

Olivella biplicata Sowerby ... . ...................•. 30-31,36 

intorta Carpenter .............. .. ............. 28, 30, 31,36 

mathewsoni Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 ~ 

pedroana Conrad ............................ 19, 24, 31, 36 

Oliverato californica Cooper ...... : ........ . ........... 14 

Omphalius viridulum var. ligula tum Menke.......... 35 

Opalia anomala Stearns ............................... 28, 100 

borealis Gould...... . . . ............................ 36 

condoni Dall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 

crenitoides var. insculpta Carpenter........ .. . .. .. 36 

mathewsoni Gabb ................. ......... .. .... 15 

varicostata Stearns ....................... :-. . . . . . . 28, 100 

- sp ................................................... 17,24 

Oregon, formations in .... :............................ 10 

fossil localities in.................................. 13 

fossils from ........................ 62, 65,111-112,120,142 

Ostrea appressa Gab b...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 
INDEX. · 259 

Page. 

· Ostrea attwoodi Gabb ... ............. .. . . ... ..... ..... 24 

bourgeoisii Remond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 24 

cerrosensis................. . . . . . . . . . . . . . . . . . . . . . . . . 107 

demissa So lander .......................... _ .... __ . 113 

idriaensis Gabb .................. .. ....... _. _ 12, 14,17,53 

Islandica Muller ........................... __ ...... 113 

Islandictts Muller .................... _ .. ..... . _... . 113 

I urida Carpenter . . .. .. . . . .. .. . . . . . . . .. . .. . . . . . .. . :>4, 122 

maxima Linne .................................. ___ 45 

palmula Conrad .. .. .. .. .. .. .. . . .. .. . . . . . . . . . . . . . . 76, 11J 

titan Conrad .... . ... .......... 19, 23, '24, 64, 70, 73, 76, 79,92 

veatchiiGabb ...................... 28,91,98,107,116,123 

vespertina Conrad ........................ _ . . . . . . . . 22, 61 

sp ............................ 30, 52,69-70,73,84-85,93,117 

Oxyrhina tumula Agassiz .............. __ .. .. ____ ...... 19 

P. 

Pachypoma inooquale Martyn ... . ..... , __ ... __ ........ 36 

sp ................... ··------·---- . .. ... .. . ... .. ... . 99 

Pallium crassicardo Conrad . . . . .. .. . . .. . .. . . . . . .. . . .. . . i1 

estrellanum Conrad ................... _·_ ............ 74 

Paludestrina curta Arnold .......................... __ 36 

stokesi Arnold..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Pandora scapha Gabb .. . . .. .. . . . . . .. .. . .. . .. .. . . . . .. .. 117 

Panomya ampla Dall ... . : ...................... 27, 31, 34, 103 

Panopea generosa Gould ........... 17, 19, 27, 31, 34, 65, 79,117 

Paracyathus ped~o~nsis Vaughan................ ... .. ~3 

Pasadena Miocene, equivalents of. ................ ·.... 10 

Paso Robles formation, equivalents of. .... .... ........ 10 

Patella traski Gab b.................................... 53 

sp ......................... :. . . . . . . . .. . . . . . . . . . . . . . . 53 

Patinopecten Dall ......................... ..... 41, 48-49,66 

caurinus Gould ...... ....... ·....... . .. . .. . .. . . . . .. . 26, 

29, 31,33-34,37,48-49,65,99,101-103,106, zzo, zzz 

coosensis Shumard .......... 23, 37, 49, 61-62,105,1,56, 158 

dilleri Dall ....................... 23, 26, 38, 49, 62, 105, 154 

healeyL ...... 26-29,38,49,63, 65,100, 103-101), 108, :216, Z18 

oweni. ............... 23-24,27,39,49,63-64,65,95, 121, 160 

. propatulus Conrad ......... 19, 21, 23, 39, 49, 64-6fi, 158, 16Z 

purisimaensis ................... 27, 39, 49, 62, 105,21:2,:214 

turneri. ....................... : .•••.... 27, 39, 49, 106, Z1Z 

Pecten Muller ................... 41-44,45-50,51-146,148-::250 

xquisulcattts Carpenter.......... . .......... . . . . . . . . 132 

(Propeamusium) alaskensis Dall.... . ............. 33, 

37, 50,127,133-134,138,:250 

( Pseudamttsium) Alaskensis Dall................... 133 

alaskensis Whiteaves ......... .................... 13i!, 140 

altiplectus Conrad... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 

altiplicatus Conrad ......... . ................. 108-109,:226 

( Plagioctenium) andersoni... .. . . . .. .. .. . .. .. .. .. . 18, 

21, 23, 37, 47, 50, 79, 82-S3, 89,196 

var. barkerianus .............. 18-19,37,50,83-84,196 

( Lyropecten) ashleyi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26, 

28, 29, 37, 49, 72, 91, 95,116,118,121, 122-123, 238,240 

auburyi. ............... ...... 26, 37, 48, 94-91), 121,210, Z12 

(Chlamys) bartschi. ............... 26,:17, 49,107-108, Z26 

bellis McCoy.............................. . . . . . . . . . . 95 

bell us Conrad ...... 16, 26, 29, 37, 48,54-55,95-96,98-99,206 

( Chlamys) bellilamellatus ..... :. 26, 28, 29, 37, 49, 108, 2:26 

(Lyropecten) bowersi.. 19, 21, 37,47, 49,70-71,141,168,170 

(Chlamys) branneri ..... 16, 19, 37, 49, 55,55-56,67,83,150 

(Chlamys) calkinsi ....... ........... 14, 37, 49, 01, 52,148 

carrizoensis ........... 19, 21, 22, 23, 37, 48,59-60,61,85, 152 

catilhformis Conrad ............................. 80, 141 

caurinus Dall .............. .. ................. 99, 101, 140 

(Patinopecten) caurinus Gould.............. .. .... 26, 

29, 31,33-34,37,48, 49, 65, 99, 101:-103, io6, 220~ ~22 

Page. 

Pecten (Plagiocter:iium) cerrosensis Gabb ......... 26,28-29, 

37, 50, 63, 77, 84,98-99,107,123-:124,125,133,232, Z42 

var. mendenhalli ...... ................ :. . . . . . . 19, 

21, 22, 23, 37, 50, 60, 63, 8-i-85, 85, 194 

cinnabarina Born . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 

(Plagioctenium) circularis Sowerby............... 33, 

34, 37, 50,87-88, 125:.126,133,:228,232 

var. ooquisulcatus Carpenter .. , ........... . . .. 33-34, 

37, 45, 46, 50, 88, 89,124,125, 132-133,244 

(Propeamusium) clallamensis............ ... ...... 14, 

16, 37, 50, 53,5 7-58,59,150 

coalingaensis. __ .................... . .... 26, 37, 48, 97, 15Z 

corripactus Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125, 232 

(Plagioctenium) cooperi.. .. 26,28-29,37,50, 124-121), 242 

coosaensis Shumard..................... . ... . ..... . 61 

( Patinopecten) coosensis Shumard...... . ......... 23, 

37, 49,61-62,105,156,158 

(Hinnites) cortezi Defrance . . . . . . . . . . . . . . . . . . . . . . . 50 

( Lyropecten) crassicardo Conrad . . . . . . . . . . . . . . 18, 21, 38, 

49, 71-73,78,81,83, 89, 92-9i!i 122,141,176,178,180 

var. hamiltoni............ 19, 23, 38, 49,73-74,81,166 

(Pseudamusium) davidsoni DalL ..... 38, 50,134,138,244 

dentatus Arnold ................. _...... .... ........ 100 

dcntatus Sower by .. . ...... __ . . . . . . . . . . . . . . . . . . . . . 134-135 

(Vola) dentatus Sower by........................... 135 

( Plagioctenium) deserti Qonrad ...... 19, 22, 38, 50, 85,196 

( Lyropecten) diabloensis Arnold. : . . . . . . . . . . . . . . . . . . 72 

diegensis Dall ........ 33, 38, 48, 60, 96, 98, 100, 127-128, 246 

(Patinopecten) dilleri Dall ...... 23, 26, 38, 49, 62,105,154 

dislocatus Say ...... ......................... ·..... . 133 

(Plagioctenium) discus Conrad .............. ,..... 21, 

23, 24, 38, 50, 71, 73, 80, 82, 86-87' 198 

( Chlamys) ·discus Conrad........ . .................. 86 

discus Cooper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82, 86 

eboreus Say ......... __ ............................. 102 

(Plagioctenium) eldridgei. .......... 23, 24, 38, 50,87, 194 

estrellanus Ashley... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 

(Lyropecten) estrellanus Conrad ... 19, 21, 23, 24, 38,49, 64, 

67, 70,72-74, 74-76,77,79-80,102,111,141,18:2, 181,., 186 

var. catalinoo .............. 23, 26, 38, 49, 63, 76-77,184 

var. terminus .................... 23, 24, 38, 49, 7 7, 190 

excavatus Anton .... 38, 47, 48, 61, 96,100,101, 134-136, 236 

(Pseudamusium) exoticus Chemnitz.............. 50 

(Patinopecten) expansus Dall ........... .. .. ..... 103-104 

Fabricii Philippi. ................................ -- 114 

(Propeamusium) fenestratus Forbes............... 50 

( Vola) florid us Hinds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 

fragilis Jeffreys .. .. . . . .. . .. . . . . .. .. .. .. .. .. .. .. .. .. 129 

(Chlamys) fucanus Dall ....... 19, 21; 23, 38, 49,66-67,164 

(Hinnites) giganteus Gray........................ 19, 

21, 22, 23, 26, 29, 33, 38, 50, 93-94,95, 109,202 

(Chlamys) hamlini ----------------- 19,38,49,67,122,166 

(Chlamys) hastatus Sower by ..................... 26-29, 

31,33-34,38,49, 69, 94,108-110,112,115,117,2£6, ZZ8 

var. albidus Dall ...................... 38, 49, 136, 21,.8 

var. hericius Gould . . . . .. . .. . . . .. . . . . . . . . . . 23, 24, 26, 

28, 29, 31,:13-34,38,49,70,109,110-111,112,115,230 

var. hindsii Carpenter......................... 26, 

29, 31, 33, 38, 49, 111-112, 115, 230 

var. navarchus Dall........................... . 26, 

28-29,33,38,49, 112-113,115,.118,230 

var. strategus Dall ........ 26, 29,33-34,38,49, 113, Z3Z 

(Patinopecten) healeyi. ....... .. ........... ·_ ... .. 26-29, 

. . 38, 49, 63, 65,100, 103-101), 108,216, 218 

Heermanni Conrad .................... 75, 79,101-102,232 

(Lyropecten) Heermanni Dall .............. 75, 79,101-102 

hemphilli Dall ...... 16, 26,28-29,38,48, 96,97-98,100,210 

he1·iceus Gould .......... : .............. :. . . . . . . . . . . 10 
260 INDEX. 

Page. 

Pecten hericeus var. hindsii Carpenter................. 111 

hericeus var. navarchus Dall. . . . . . . . . . . . . . . . . . . . . . . . ·112 

var. strategus Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 

(Chlamys) hericeus·Gouid ... ·. .. . . .. . . . . .. .. . ... .... 110 

var. strategus Dall .... ........... . :. . . . . . . . . . . . 113 

her'icius Gould . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 

( Chlamys) hericius var. alhidus Dall. . . . . . . . . . . . . . . . 136 

Humphreysii ................................ .'. .... 141 

( Chlamys) hydei Arnold ................. .. . ·.. . . . . . . 69 

inca Orbigny. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 

(Propeamusium) inequisculptus Tiberi . . . . . . . . . . . 50 

intermedius Conrad ... ·... . . . . . . . . . . . . . . . . . . . . . . . . . . 128 

(Propeam:usium) interradiatus Gab b.............. 14, 

38, 50, 53-54, 59, 91, 1/,S 

irradians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 

Islandica Muller................................... 114 

Islandicus Chemnitz............. . ........... .. .... 114 Islandicus Cooper;.;............................... 114 

(Chlamys) Islandicus Muller......... . ............ 16, 

26, 29, 33, 38, 49, 52, 55,107,112, 113-114,115,120,234 

J effersonius Say ................ ; . . . . . . . . . . . . . . . . . . 78 

(Chlamys) jordani Arnold......................... 26, 

29, 31, 34, 38, 49,114-115,232 

Pecten keepi .... 19, 21, 22, 23, 38, 48,60-61,85,135,154,156 

(Chlamys) landesi n. sp ............. 14, 38, 49, 51-o2, 148 

laqueatus Sower by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 

(Chlamys) latiauritus Conrad ... .. 26-27,29-30,33-34,38, 

47, 49, 82, 91,108, 115-116; 123,129,130,131,137,236 

var. cerritensis n. var ... 33-34, 38; 49,108, 129-130,236 

var. delosi n. sp . ... .......... ... 33-34,38, 49, 130, 236 

var:jragilis Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . • 129 

var. fucicolus Dall ............. 33, '38, 49,130,131,236 

var. inonotimeris·Conrad .... 33-34,38,49,82,131,236 

( Chlamys) I a wsoni n. sp ........•• 27, 38, 49, 117 -11~, 234 

lecontei n. sp ..................... 27; 38, 48, 94, 98,107, 210 

(Pseudamusium) lompicoensis ...... 21, 38, 50, 89,190, 198 

(Amusium) lompocensis ............. 38, 50, 73,92-93,200 

madisonius Say ........ , ..... , . . . . . . . . . . . . . . . ..... 141 

(Lyropecten) magnolia Conrad .............. ·...... 19, 

39, 49,·70--72, 77-79,80--81,107,192,194 

magnolia Dall ........... ~ .. · ... ·. ·. . . . . . . . . . . . . . . . . . . . 72 

maxim us J;.inn~ .. ....... .. ........ ... .... :. . . . . . . . . 48 

MeekiiConrad ....................... ....... :. 101-102,222 

ineekii Merriam .......... :......................... 99 

membranosus Morton .. ::.;...... . . . . . . . . . . . . . . . . . 52 

merriami. ............................... 27,39,48,99,204 

mesotimeris Sower by.... . . . . . . . . . . . . . . . . . . . . . . . . . . 115 

(Lyropecten) miguelensis ... 19;39;49, 79-80,102,188,190 

( Leptopecten) monotimeris Conrad. . . . . . . . . . . . . . . . . . 131 

(Amusium) mortoni Ravenel...................... 92 

(Plagioctenium) neahensis .. ~. 18, 21, 23, 39, 50,87-88,174 

nevadan us Uonrad ......... ~. ~....... . . . . . . . . . . . . . 1 U 

nevadamts·Conrad ~ .. ~ •. ; ~. .......... ............. 70 

(Plagioctenium) newsomi Arnold................... 132 

nodosus ...................... : .......... : .... :: .. :. 49.129 

(Chlamys) nutteri.: .... ·19;21, 23, 27, 39, 49,67-68, 105> 166 

(lEquipecten) opercularis Linn~................. . 49 

(Chlamys) opuntia Dall ......•...... ... ~ .......... 27-29, 

39, 49, 91, 107. 116, 118, 123, 226 

(Patinopecten) oweni . :._:: ........... : .. :......... 23, 

24, 27, 39, 49,63-64,65,95,121,160 

(Plagioctenium) pabloensis Conrad............... 23, 

39, 50, 63, 86, 88-89, 198 

' (lEqnipecten) palmeri Dall .. ~: ...... 39,49,136-137,244 

(Chlamys) parmeleei Dall ... .-..................... 27, 

• . '29, 39, 49, 68,100,-108, 119,120--121,226 

(Plagiocteninm) paucicostatusCarpenter. 39,50,137, 222 

halei Conrad ........... :.-: ;.:: ................. ~:.. 114 

Page. 

Pecten (Pseudamusium) peckhami Gabb... .. . . .. . .. . 16, 

17, 19, 21, 39, 47, 50, 55, 56-57' 89,138-139,150 

(Pseudamusium) pedroanus Trask................ 21, 

23, 27, 39, 50, 90-91,92,116, 123,138-139, 200 

(Lyropecten) perrini ......... 19, 21, 39, 49, 80-81,172,174 

(A:rimsium) pleuronectes Linn~ ............. ~..... 50 

poinatia Valenciennes............................. 125 

(Chlamys) proavus n. sp ...... 11, 12,39, 49, 52,52-53,148 

(Patinopecten) propatulus Conrad................ 19, 

21, 23, 39, 49, 64-65, 158, 162 

propatulus Cooper ................................ 101, 106 

(Pseudamusium) Sowerby..................... .... 50 

( Patinopecten) purisimaensis... 27, 39, 49, 62, 105, 212, 214 

pyxidatus Carpenter .................. : ........ : 1.U,142 

, (Pseudamusium)randolphiDall. 39, 50, 89,91,138-139, '21.0 

var. tillamookensis n. var ............. 39, 50, 139, 240 

(Propeamusium) riversi. ... 27, 29, 39, 50, 126-127,134,232 

rubidltS Hinds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112, 113 

sanctrecruzensis ............... 16,17, 19, 39, 48, 5<1-55, 150 

(Chlamys) sespeensis ...... .... ....... 19, 39, 49, 69, 70,160 

var. hydei n. var ...... .. .. 19, 39, 49,69-70,79,83,154 

(Propeamusium) stanfordensis........... .. . . . . . . . 14, 

. 19, 21, 39, 50, 53,58-59,91-92,190 

Pecten stearnsii Dall ......... . .................... 27-29, 

31, 39, 48, 60, 63, 77, 91, 96, 98, 100,108, 116, 123, 128, 135,208 

subcrenatus Carpenter............................ 142 

(Nodi pecten) subnodosus Sowerby .. .............. 33-34, 

39, 49,107,128-129,248,250 

(Plagiocteni·um) subventricosus Dall .......... 123, 1"25, 232 

swiftii Beri:J.hardi ............. . . ·'- . . .......... 46,119-121 

thalassinum Dall ....... :. . . . . . . . . . . . . . . . . . . . . . . . . . 46 

townsendi Gould .... ; ...... : ..... ............... :. 14-2 

traski Gabb .......................... , ............. · 53 

tnmbezensis Orbigny ... ·......... ....... .. ... ...... 1Hi 

tumid us Sower by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 

tltnica Philippi..................................... 115 

(Patinopecten) turneri ....... · ...•. 27,39,49,106,212,214 

twobarensis Arnold ....... .. ....... ...... ... . : . . . . . . 54 

(Pseudamusium) vancouverensis Whiteaves...... 39, 

. 50,101,133,139,14-0,248 

(Lyropecten) vaughani.: ............ 19, 39, 49, 81-82, 190 

(Nodipecten) veatchii Gabb ... 27, 39, 49,·98,·106-107, 224 

· ( Plagioctenium) veritricosus Arnold ..... ; ...... , . . . 132 

l•entricosus Dall ........ : .......... ·..... . . . . . . . . 132 

ventricosus Gabb ... . ...... ... .... ....... ~ . . . . . . 132 

t•entricosus Sowerby ........................ :. 123, 125 

vogdesi ................. 33--34, 39, 48, 100-101,135, 210, 212 

volrejormis Conrad ................ · .........•... 74, 75, 184 

(Chlamys) washburneL .. · ......... 27,39,49,119-120,234 

(Chlamys) wattsi .... ....... .... .. ..... ...... ...... 27, 

39,4-9,67-68,95,119,120-121,122,166 

var. morani ........... . . ...... 27, 39, 49,121-122,164 

(Propeasmusium) waylandi.:. 14, 16, 39, 50, 53, 58-59,150 

Yessoensis Carpenter........................... . ... 101 

yessoensis Jay . . . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . . . 102 

sp ................................ : .. : ....... 59,63,94,117 

s. s. Muller ......... : ... : ..... : ............. 41, 46, 4-8, 236 

Pectens, collection of, examination of . . . . . . . . . . . . . . . . 8 

· geologic range of ................ : ................. 37-40. 

localitieswherefound, lists of. 11, 13, 16, 18,20--22,26,29,32 

plates showing .............. ; . . . . . . . . . . . . . . . . . . . 148-250 

summary of. .......... .............. :. . . . . . . . . . . . . . . 44 

unidentifiable specimens of .. ~ ... . .. ......... 44,141,142 

value of, in stratigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Pectiriacea .. -............................... -..... ~ ..... 41-250 

Pectinidre ••• · ... . .......... ... ........................ 41-250 

Pectunculus patulus Conrad ... ~ ........ : .. .-........... 118 

Pelecypoda .... 12, 14, 17, 19, 21, 22,23-24,27,28, 30,33-34,41-250 
INDEX. 261 

Page. 

Periploma argentaria Conrad......................... 34 

sp.......... . ....... ........ .................... .... 19 

Perissolax blakei Cunrad.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 15 

tricarnatus Weaver................................ 12 

sp........ ............ .... ............ ............ .. 17 

Petri cola carditoides Conrad . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

cognata C. B. Adams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

denticulata Sower by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

Petricolaria cognata C. B. Adams . . . . . . . . . . . . . . . . . . . . . 34 

Phacoidesacutilineatus Conrad .............. 17, 19, 22, 24, 27, 

28, 31, 34, 57, 65, 79, 83, 89, 95,104-105,107-108,117 

californicus Conrad ........................ 31, 34, 95, 121 

crenulata ........... ·•••. ... . . . . . . . . . . . . . . .. . . . . . . .. 21 

nuttalli Conrad ....•••••..................... 27-28,84,95 

richthofeni Gabb ..•..•••................... 19, 79, 95,104 

tenuisculpta Carpenter............................ 34 

turneri Stanton.................................... 12 

sp .. ................................ 17,55, 57, 73,84, 93,117 

Phasianella com pta Gould . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Pholadidea penita Conrad ............................ 31,34 

Pholadomxa nasuta Gabh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Pholas crucigera Sower by............................. 22 

Phorcus pulligo Martyn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

Physa heterostropha Say . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Pinna alamedensis Yates. . . . . . . . . . . . . . . . . . . . . . . . . . . 19, 23, 83 

Pisania fortis Carpenter ......... .. .. .. ............. 24, 36, 64 

Pisces.......... . . . . . . . . . . . . . ·.... . ... ................ 19, 87 

Pismo formation, equivalents of . . . . . . . . . . .. . . . . . . . . . . 10 

Plagioctenium ........................................ 41, 50 

andersoni ............ 18, 21, 23, 37, 47, 50, 79,82-83,89,196 

var. barkerianus ......... _·_ ... 18-19,37,50,83-84,196 

cerrosensis Gabb ................... .... ........ 26, 28-29, 

37, 50, 63, 77, 84,98-99,107, 123-124,125,133,232,242 

var. mendenhalli.............................. 19, 

21, 22, 23, 37, 50, 60, 63,84-85,85,194 

circularis Sowerby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33-34, 

37, 50,87-88, 125-126,133, 228,232 

var. ::eq uisulca tus Carpenter.. . . . . . . . . . . . . . . . . 33-34, 

37,4-5, 46, 50,88-89,124-125, 132-133,244 

cooperi ...................... 26,28-29,37,50, 124-126,242 

deserti Conrad ....................... 19, 22, 38, 50, 85, 196 

discus Conrad •.... 21,23-24, 38, 50, 71, 73, 80, 82, 86-87, 198 

eldridgei ............................. 23, 24, 38, 50, 87, 194 

neahens.is ...................... 19, 21, 23, 39, 50,87-88,174 

newsomi Arnold.................................... 132 

pabloensis ................ . .... 23, 39, 50, 63, 86, 88-89, 198 

paucicostatus Carpenter .................. 39, 50,137,222 

subventricosus Dall.. .. .. .. .. . . .. . .. . .. .. . .. .. 123, 125, 232 

ventricosus Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 

ventricosus Sowerby .......................... 123, 125, 132 

Plagiostoma anntLlatu.s Trask. . . . . . . . . . . . . . . . . . . . . . . . . . . 90 

Pedroana Trask. .. . . . . . . . . . .. . .. . . . . . .. . . . .. . .. . .. . 90 

truncata Trask.. . .. . .. .. . .. .. . .. .. . . .. . .. . .. . .. .. . . 90 

Planorbis tumid us Pfeiffer .. .. .. .. .. .. .. .. . .. . .. .. .. . . 36 

vermicularis Gould........................... . .... 36 

Platyodon can cella tus Conrad . .. . .. .. .. .. . .. . .. .. . . .. 34 

Pleistocene rocks, formations of. ................. 9-10,31-37 

fauna of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33-37 

occurrence of...................................... 9, 31 

pectens of. . .......... . . . . . . . . . . . . . . . . . . . . . . . 33, 37-40, 43, 

94,101,103,109,111-114,116,126-136,210-212,224, '250 

Plesiastrea californica Vaughan............... . ....... 22 

Pleurotoma bartschi Arnold ........................... 31,36 

carpenteriana Gabb .............................. 36,117 

cooperi Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

dalli Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 86 

boo veri Arnold . . .. . . . . .. .. . .. . . . . .. . . . . .. . . . . . . . . . 36 

pedroana Arnold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36, 84 

Page. 

Pleurotoma perkinsiana Cooper . . . . . . . . . . . . . . . . . . • • . . 15 

perversa Gabb. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 31, 36, 103 

raricostataGabb.................................... 17 

renaudi Arnold .... , ............................... 31, 36 

smithi Arnold ..................................... 31, 36 

tryoniana Gabb ................................... 36, 117 

,jip •.. -.•......... ~ ...•...•..•....•• 17, 28, 30, 84, 91,116,123 

Plicatula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 

ostreiformis Stanton.................... . .......... 12 

Pliocene rocks, fauna of. .. .. .. . .. .. .. .. .. . .. .. .. .. .. .. 26-31 

formations of .......................... .. ..... 9-10,25-31 

occurrence of. . .. . .. . . .. . .. .. . .. . .. .. .. . . . . . . . .. . . . 9, 25 

pectens of. ...... . ........... ... .. .. 26-27,29,37-40,42-43, 

62, 64, 77, 91,94-127, 15'2, 164-166,200, '204-228, 232-24'2 

Pododesmus macroschisma Deshayes .... ... . ....... 28, 30,34 

Polynices recluziana Desha yes........................ 22 

Pomaulax undosus Wood........... .. ................. 36 

sp.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 

Porter, Wash., rocks near........ ....... . .. ........ . ... 15 

Potamides carbonicola Cooper. . . . . . . . . . . . . . . . . . . . . . . . . 15 

davisiana Cooper . .............. . .................. 15 

Priene oregonensis Redfield .. . . .. .. .. .. .. .. . .. .. .. .. . . 28, 

31, 36, 91, 95,103,116-117,121,123 

sp.................................................. 24 

Prionodesmacea ...................................... 41-250 

Propeamusium Gregorio .............................. 41, 60 

alaskensis Dall ............ 33, 37; 50,127, 133-134,138,250 

clallamensis ................ 14, 16, 37, 50, 53,67-58,59,150 

fenestratus Forbes.................. . .............. 50 

inequisculptus Tiberi.............................. 50 

interradiatus Gabb ............ 14, 38, 50, 63-54,59,91, 148 

riversi ................... : .. 27, 29, 39, 50,126-127,134, 23'2 

stanfordensis ......... 14, 19, 21, 39, 50, 53, 58, 59,91-92,190 

waylandi ...................... 14, 16, 39, 50, 53, 68-89, 150 

Protocardia centifilosa Carpenter .. . ................... 31,34 

Psammobia edentula Gabb ........ . ................... 19,34 

Psephis lordi Baird . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

salmonea Carpenter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

tantilla Gould .................................... 34, 103 

Pseudamusium H. and A. Adams ..................... 41, 60 

Alaskensis Dall. . .. .. .. . . .. . . . . .. .. . . .. . . . .. . .. . . . .. 133 

davidsoni Dall ........................ 38, 50,134, 138, '244 

exoticus Chemnitz..................... . ........... 50 

lompicoensis ........................ 21, 38, 50, S9, 190, 198 

peckhami Gabb ................................... 16-17, 

19, 21' 39, 47, 50, 55,66-57' 89,138,139, 150 

pedroanus Trask................................... 21, 

23, 27, 39, 50,90-91,92,116,123,138-139,200 

randolphi Dall ................. 39, 50, 89, 91, 138-139, 240 

var. tillamookensis .................. 39, 50, 139,240 

vancouverensis Whiteaves .... 39, 50,101,133,139, 140,_248 

Pseudocardium gabbi Remond .... ... . ..... ........... 24. 

Pteria limula Conrad.................................. 52 

Pterohytis foliatus Martyn . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

nuttalli Conrad......... .. ......................... 36 

Pteronotus festivus Hinds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Puget group, equivalents of . .. .. .. . .. .. .. . .. .. .. . . . . . . 10 

Puncturella cucullata Gould .......................... 31, 36 

galeata Gould . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 36 

Purisima Creek, Cal., rocks near . . . . . . . . . . . . . . . . . . . . . . 25 

Purisima formation, character of. . . ................... 25-26 

equivalents of.................. ..... ............... 10 

fossils of ........................................... 26-28 

occurrence of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 25-26 

pectens of. ................................... 26-27, 37-40 

Purpura canaliculata Duclos .......................... 24,.30 

crispata Chemnitz ... · .......................... 28, 36, 117 

saxicola Valenciennes .......................... 24, 30,36 
262 INDEX. 

Page. 

Pyramidella conica var. variegata Carpenter . . . . . . . . . 36 

Pyrula sp ................................ ... .....•.... 19, 117 

R. 

Ran ella californica Hinds . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 36, 95 

sp .. ·......•.••.•........... . .. .. ... ... ........ ...... 52 

Range of California pectens ...................... . .... 37-40 

See also particular species. • 

Recent time, pectens of. : ... 37-40, 43-44; 94, 103,111-114, 116, 

126, 128, 130, ~OfZ, fZfZO-fZ2fZ, fZfZ6-236, fZ40, fZ44, 2t,S-250 · 

Rictaxis punctoccelata Carpenter..................... 34 

Rim ella canalifera Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

simplex Gab b...................................... 15 

Rissoa acutelirata Carpenter.......... . ... .. ... ...... . 36 

Rock Creek Eocene, equivalents of.......... . . . . . . . . . . 10 

Rostellaria indurata Conrad .... ............. . ... .. -. ' 28, 105 

Rupellaria lamellifera Conrad......................... 34 

s. 

Salinas Valley, Cal., formations in .................... 10,24 

San Diego formation, equivalents of . . . . . . . . . . . . . . . . . . 10 

fauna of......................... . ........ .. ....... 28 

San Joaquin Valley, formations in ............. ...... . 

San Juan de Fuca Strait, rocks near . . . . . . . . . . . . . . . . . . 15 

San Lorenzo formation, character of................. . 16 

equivalents of..................................... 10 

fauna of . . ......................................... 16-17 

occurrence of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 16 

pectens of. ...................................... 16, 37-40 

San Pablo Bay, Cal., rocks near....................... 22 

San Pablo formation, character of . . . . . . . . . . . . . . . . . . . . 22 

equivalents of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

fauna of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24 

occurrence of...................................... 9, 22 

pectens of. ...................................... 23,37-40 

San Pedro, Cal., rocks from........................... 32 

San Pedro formation, character of . . . . . . . . . . . . . . . . . . . . 32 

equivalents of . . . . .. . . . . . . . . ...... ... . ... .. .. . . . .. . 10 

fauna of ....................... :. . . . . . . . . . . . . • . . . . . 33-37 

occurrence of.................................. . . . . 9, 32 

pectens of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33, 37-40 

Sanguinolaria nuttalli Conrad......................... 34 

Santa Cruz, quadrangle, rock in ........ . ........... ·... 16 

Santa .1\fargarita formation, equivalents of............ 10 

fauna of........................................... 24 

Santa Rosalia, Mex., fossils from ...................... 84-85 

Saxidomas gibbosus Gabb .... ............. 19, 24, 27, 30, 64,83 

gracilis Gould ........................... _ .. _. 24, 30, 34, 73 

sp ....................................... ..... ...... 21 

Scala bellastriata Carpenter........................... 36 

crebricostata Carpenter............................ 36 

hemphilli Dall.. ................ , .......... . . . . . . . . 36 

hindsii Carpenter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

indianorum Carpenter ............................. 31, 36 

stearnsii Dall " .... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 100 

tincta Carpenter.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 36 

sp .. _ ............ ............ .. ....... ... ........... 17,117 

Scalaria mathewsoni Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

Schizaster lecontei Merriam........................... 12 

Sconsia ti.Iberculatus Gabb ~. ............ ............. 15 

Scutella fairbanksi Merriam ..... . .... ............ 19, 70, 122 

gabbi Remond..................................... 23 

interlineata Stimpson ............................. 27,30 

sp .. · .............. _ ............................ _. 92-93, 103 

Seila assimilata C. B. Adams.......................... 36 

Semele decisa Conrad ......................... :. . . . . . . 34 

pulchra Sower by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34, 85 

var. montereyiArnold........ ....•. ...... ..... 34 

sp ............................................ 12, 21, 53, 57 

Page. 

Septifer bifurcatus Conrad . . . . • . . • • . . . . . . . . . . . . . . . . . . . 34 

dichotomus Gab b.................................. 14 

Serpula sp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Serpulorbis squamigerus Carpenter .................... 28, 36 

Siderastrea californica Vaughan...................... 22 

Sigaretus debilis Gould ................................ 28,36 

scopnlosus Conrad ... ........... .. ................. 17,19 

!'p ......•....................... ........ ' . ....•..... 65-66 

Siliqua lucidaConrad ............................ . ..... 27,34 

patnla Dixon ....... .' ..... .... ....... .... ... 27, 28, 30,103 

var. nuttalli Conrad........................... 34 

· sp........ .. .. ............. ...... ....... . ...... . .... 21 

Siphonalia kellettii Forbes.............. . . . . . . . . . . . . . . 36 · 

lineata Stanton.......................... . . . . . . . . . 12 

Siphonodentalium pusillum Gabb............ . ........ 15 

Solariella cidaris A. Adams. . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

peramabilis Carpenter .. .... , .................. , ... 28, 31 

SolariumamoenumConrad........ ............ ... ..... 17 

sp .. .. ................................ · .............. 17,19 

Solemya ventricosa. Conrad yo . . . . . . . . . . . . . . . . . . . . . .. . 17 

sp .... ............. ...... ................. : ......... 57-58 

Solen curtus Conrad................ . . .. ............... 17 

diegoensis Gabb .................. .....•........... 14 

. parallel us Gab b.................................... 12 

sicarius Goul i .. . .... 19, 24, 27, 30, 31, 34, 79, 84, 95, 99,103 

stan toni Weaver................................... 12 

sp... ..................... ......... . ................ 24 

Sooke beds, equivalents of . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Spirocrypta pileum Gab b........... . .................. 15 

Spiroglyphus lituella Morch,... .. . . . . . . . . . . . . . .. . . . . . . 36 

Spirotropsis Smithi Arnold . . . . . . . . . . . .. . . . . . . . . . . . . . . . 36 

Spisula catilliformis Conrad ..................... 27-28,34,67 

falcata Gould ................................... 27, 30,34 

sp........ ............... . ...... ....... ......... .... 66 

Spondylus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . j6 

Estrallensis Conrad . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . 71 

Estrellanus Conrad................................. 71 

Stalagniinm concentricum Gabb...................... 14 

Stanton, T. W., on Tejon formation fossils .. ·······'··· 14 

Stephanocoenia fairbanksi Vaugha~.................. 22 

var. columnarisVaughan ....... , .... ..... .. ... .... 22 

Stratigraphy, value of Pecten genus in determining.. 7 

Strep13idura pachecoensis Stanton . . . . . . . . . . . . . . . . . . . . . 12 

Stromb\].s granulatus Sowerby......................... 2'2 

sp ..... .. ............. ............. ....... ........ ,. 22,85 

Strongylocentrotus franciscan us Agassiz.............. 33 

purpuratus Stimpson .......................... 28, 33, 120 

Styliferina tenuisculpta Carpenter.................... 36 

Surcula claytonensisGabb... .. . .. ... . ... .. ....... ..... 15 

crenatospira Cooper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

inconstans Cooper........................... . ..... 15 

monilifera Cooper. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

prreattenuata Gab b...................... . . . . . . . . . . 15 

raricostata Gab b................................... 15 

sinuata Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

T. 

Tagelus californian us Conrad......................... 34. 

Tamiosoma gregaria Conrad . . . . . . . . . . . . . . . . 23, 24, 64, 76, 111 

Tapes conradiana Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

cretacea Gabb..................................... 14 

lacineata Carpenter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

quadrata Gabb .................................... 12, 14 

staleyi Gabb.~ .............................. 24,27;30,103 

staminea Conrad ....... , . . . . . . . . . . . . . . . . . . . . . . . 24, 28, 30 · 

tenerrima Carpenter .............................. 27,34 

truncata Gab b ..................................... 19,83 

sp .................................................. ·51 
INDEX. 263 

Page. 

Taranis strongi Arnold.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 36 

Tejon formation, character of......................... 13 

equivalents of..................................... 10 

fauna of .................... ....................... 14-15 

occurrence of...................................... 9, 13 

pectens of ................................ 14, 37-40, 51, 54 

Tellina ::equalis Gabb ........... . ....... . ....... ... . :. 12 

arctata Conrad ..... ... . . ........ .. ...... . ...... ... 17,66 

bodegensis Hinds ................................. 19, 34 

californica Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

congesta Conrad ............................. 20,21,27,57 

hoffmanniana Gabb..... .. .. . . . . . . . . . . . . . . . . . . . . .. 12 

hornii Gabb ..... ..... ......................... .... 12,14 

id::e Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34, 84, 104 

longa Gabb........................................ 14 

martinezensis Weaver............................. 12 

oregonensis Conrad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

remondi Gabb.......... ..... ... . . . ......... .. . . ... 14 

rubescens Hanley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

undulifera Gab b.................. ... ... .. ......... 12 

sp ........................... 19,27,55,58-59,66,73,83,117 

a.'erebra califqrnica Gabb ..... ·......•.............. . .. 15 

simplex Carpenter ................................ 31,36 

wattsiana Cooper. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

sp.... .... ... ..... .... ........ ........ .............. 84 

Terebratalia smithi Arnold............................ 30 

hemphilli Dall ..... ...... ... , . . . . . . . . . . . . . . . . . . . . . 107 

Terebratella transversa Sowerby . . . . . . . . . . . . . . . . . . . . . . 120 

sp ............................................... 19, 83,92 

Trebratula nitens Conrad . . . . .. . . . . . . . . . . . . . . . . . . . . . .. 17 

sp ........................ . ......... .... ." ...... 12, 53, 57,58 

Terebratulina tejonensis Stanton ..................... 12,53 

Teredo sp ........................................... 12, 55, 57 

Thalotia caffea Gabb .................................. 31, 36 

Theliostyla triangulata Gab b.......................... 15 

Thracia karquinesensis Weaver. . . . . . . . . . . . . . . . . . . . . . . 12 

dilleri Dall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 

trapezoides Conrad ... . . ......... .... .. .... . 17, 31, 34, 103 

Thyasira bisecta Conrad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

gouldii Philippi .............................. . .... 31, 34 

sp............... ......... ..... ..... ..... ... .... . . . . 17 

Tivela crassatelloides Conrad . . . . . . . . . . . . . . . . . . . . . . . . . 34 

ineziana Conrad ............................. 19, 22, 79,83 

Tornatina cerealis Gould.............................. 36 

culcitella Gould ........... . ...... ..... ..... ... .... 28, 36 

eximia Baird . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

harpa Dall... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

'.rrachycardinm sp ..................................... 19,79 

Trachytriton diegoensis Gab b......................... 15 

fusiforme Gabb ..................... ·. . . . . . . . . . . . . . . 15 

tejonensis Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

Tresus nuttalli Conrad .................... 24, 27, 30, 34, 73,103 

sp ................................................. 24,64 

Triforis adversa Montagne ............ .. .. .. .. . . ... .. . 36 

Tritonium californicum C+abb ...... . ............. .. 12, 15,53 

diegoensis Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

eocenicnm Weaver.......................... ...... 12 

fusiforme Gabb . . . . . . . . . .. . .. .. . . . .. . .. . .. . . . . . .. .. 15 

gibbosus Broderip....... .. . . . . . . . . . . . . . . . . . . . . . . . . 36 

horni Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

impressnm Weaver................................ 12 

paucivaricatum Gabb .......... ... .. .. .... .. . . . ... 15 

pulchrum Weaver . . . . .. . .. . .. .. . . . . .. .. . . . . .. . . . . . 12 

tejonensis Gabb . .. .. . .. . .. .. . . . . .. .. . . .. .. .. . .. .. . - 15 

whitneyi Gabb .. . . . . .. .. .. . . .. . .. . .. . .. . . . . . . . .. .. 15 

sp ............................ 19, 24, 28, 52, 55, 73, 83, 93,104 

Tritonofusus cretacea Gabb . .. . . . . . . . . .. . . . . . . .. . . . . . . 15 

Trivia californica Gray...... . . . . . . . . . . . . . . • . . . • . . . . . . . 36 

Page. 

Trivia solandri Gray .......... .... ~................... 36 

Trochita costellata Conrad .... .. ..... . ...... 17, 19, 79, 83,117 

filosa Gabb . . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 30, 65, 84, 86, 104 

inornata Gab b ................................... 117-118 

sp ......................... .. ............ . ..... ..... ··24, 95 

Trocliocyathus californicus Vaughan................. 14 

stan toni Vaughan....... ........ ............ .. .... 14 

striatus Gabb . . . .. . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . 14 

zitteli Vaughan................................... 12 

Trophon cerritensis Arnold . . . . .. .. . .. .. .. . . .. . . .. . . . . 36 

gracilis Perry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 36 

multicost~;ttus Eschscholtz ........... ... .......... 36,103 

orpheus var. pr::ecursor Arnold ............. ... .... 31, 36 

pacificus Dall ........... . .......................... 31,37 

pedroanus Arnold ................ 1• .. .. • .. • • • .. • • • • 36 

ponderosnm Gabb .............................. 19, 24, 84 

stuarti Smith ...................................... 31,37 

tenuisculpta Carpenter............................ 31 

triangulatus Carpenter............................ 37 

Tunnel Point beds, equivalents of..................... 10 

Turbinella crassitesta Gabb . . .. . . . . . .. . . .. .. . . .. . .. . . . 12 

sp.......... ..... .. . .. ...... . ... ... ...... ... ........ 52 

Turbo sp.. ........ .. . . .. . .. . . . . . . .. . . .. . . . . . . . . . . .. .... 53 

Turbonilla adleri Dall and Bartsch. . . . . . . . . . . . . . . . . . . . 37 

arnoldi Dall and Bartsch . . . . . . . . . . . . . . . . . . . . . . ... . . 37 

aurantia Carpenter................................ 37 

crebrifilata Carpenter..... . ........................ 37 

gibbosa Carpenter................................. 37 · 

la.ninata Carpenter................................ 37 

latifundia Dall and Bartsch . .... ·...... . . . . . . . . . . . . 37 

lowei Dall and Bartsch. . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 

muricataGould.................................... 37 

pentalopha Dall and Bartsch...................... 37 

~imilimis C. B. Adams............................. 37 

stearnsii Dall and Bartsch. . . . . . . . . . . . . . . . . . . . . . . . . 37 

subcuspidata Carpenter . . .. . .. . . .. .. . . .. . . .. . .. . . . 37 

tenuicula Gould . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 

torquata Gould....... .. .. .. .. .. .. . . .. . . . .. .. .. . . . 37 

torquata var. stylina Carpenter ............ : . ..... : 37 

tridentata Carpenter .. . . . . . .. . . . . . .. .. .. . . .. . . . . .. 37 

Turner, H. W., on San Pablo formation fossils . . . . . . . . 23 

Turris sp ..... . . _ .: . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . 12 

Turritella conica Weaver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

coo peri Carpenter . . . . . . . . . . . . . . . 28, 31, 37, 95, 100, 104, 117 

· hoffmanni Gabb .............. 18, 19, 22,69-70,73,79,93-94 

infragranulata Gab b................ ... .......... .. 12 

jewetti Carpenter ...... ... ................ . ........ 31, 37 

martinezensis Gab b .................. ... ........... 12,15 

ocoyana Conrad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18, 19, 83, 84 

pachecoensis Stanton. ............................. 12 uvasana Conrad .................... ... ... ....... .. 51,52 

variata Conrad.................................... 19 

sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 30, 58 

u. 

Unio penultimus Gab b ................ !.... ............ 14 

Urolophus halleri Cooper. .... ......................... 37 

Urosyca caudata Gab b................................. 12 

robusta Weaver............................... . . . . . 12 

v. 

Vaqueros formation, character of...................... 18 

equivalents of ... ...... ·.. ... ....................... 10 

fauna of ................. .... · .... ..... ............. 18-19 

occurrence of .............................. :. . . . . . . 9, 18 

pectens of. ................................... 18-19, 37-40 

Vaqueros Valley, Cal., rocks in........................ 18 

Venericardia barbarensis Stearns ......... · ..........•.. 31, 8~ 
264 INDEX. 

Page. Page. 

Venericardia planicosta Lamarck .................... 14, 52 Volvarina varia Sowerby .... ............ .............. 37 

planicosta var. hornii Gab b ................ ...... 12, 14,51 Volvula cylindrica Carpenter......................... 37 

ventricosa Gould .................... 30-31,34,100,117-118 

sp .................................................. 57,66 w. Venus requilateralis Gabb...................... ... .. .. 14 

fl.uctifraga Sowerby ...................... :. . . . . . . . . 34 

War!hington, formations in............................ 10 

fossils from ......................... 52,57-59,65-67,87-88 

gnidia Broderip and Sower by...... . . . . . . . . . . . . . .. 34 Whitney, J. D., on Martinez formation................ 11 lenticularis Gabb.................................. 17 

neglecta Sowerby.................................. 34 

on Tejon formation................................ 13 

Wildcat formation, equivalents of..................... 10 

pertenuis Gabb ...... ........ .......... 19, 24, 27, 73, 76,83 

simillima Sowerby ............. · ................... 31, 34 X. 

succincta Valenciennes............................ 34 

tantilla Gould..................................... 34 Xenophora zitteli Weaver .. ' ............ :.............. 12 

sp .................................................. 83-84 

Vermicularia sp . .. .. .. .. . .. .. .. .. .. .. .. .. .. . .. .. . . . .. . 37 Y. 

Verticordianovemcostata Adams and Reeve.......... 34 Yoldia cooperi Gabb ............... ~ ............. 19,27,34,83 

Vitrinella williamsoni Dall.......... ..... . . .. ... . .... . 37 impressa Conrad· ........................ -· ......... 17,55 

Vola dentatus Sowerby . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 scissurata Dall .............. ...... ...... ....... 27, 34,103 

floridue Hinds ................ . .. . .. _._............. 127 

sp ... ~ ............................................. 95,100 z. Volutilithes~p ... ... : ...... ,........ . .... . ............. 57 Zirphrea gabbi Tryon .................................. 27, 34 

Voluta sp .. .... .................. ..... ..... . .. ...... ... 28,86 sp. ................................................. 24 
CLASSIFICATION OF THE PUBLICATIONS OF THE UNITED STATES GEOLOGICAL SURVEY. 

[Professional Paper No. 47.] 

The serial publications of the United States Geological Survey consists of(l) Annual Reports, (2) 

Monographs, (3) Professional Papers, (4) Bulletins, (5) Mineral Resources, (6) Water-Supply and 

Irrigation Papers, ( 7) Topographic Atlas of the United States--folios and separate sheets thereof, ( 8) 

Geologic Atlas of the United States-folios thereof. The classes numbered 2, 7, and 8 are sold at cost 

of publication; the others ar8 distributed free. A circular giving complete lists may be had on 

application. 

Most of the above publications may be obtained or consulted in the following ways: 

1. A limited number are delivered to the Director of the Survey, from whom they may be obtained, 

free of charge (except classes 2, 7, and 8), on application. 

2. A certain number are delivered to Senators and Representatives in Congress, for distribution. 

3. Other copies are deposited with the Superintendent of Documents, Washington, D. C., from 

whom they may be had at practically cost. 

4. Copies of all Government publications are furnished to the principal public libraries in the 

large cities throughout the United States, where they may be consulted by those interested. 

The J>rofessional Papers, Bulletins, and vVater-Supply Papers treat of a variety of subjects, and the 

total number issued is large. They have therefore been classified into the following ~eries: A, Economic geology; B, Descriptive geology; C, Systematic geology and paleontology; D, Petrography and 

mineralogy; E, Chemistry and physics; F, Geography; G, Miscellaneous; H, Forestry; I, Irrigation; 

J, vVater storage; K, Pumping water; L, Quality of water; M, General hydrographic investigations; 

N, 'Vater po,ver; 0, Underground waters; P, Hydrographic progress reports. This paper is the 

seventy-sixth in Series C, the complete list of which follows. (PP=Professional Paper; B=Bulletin.) 

SERIES C. SYSTEMATIC GEOLOGY AND PALEONTOLOGY. 

B 3. Fossil faunas of Upper Devonian, along the meridian 76° 30', from Tompkins County, New York, to Bradford County, 

Pennsylvania, by H. S .. Williams. 1884. 36 pp. (Out of stock.) 

B 4. Mesozoic fossils, by C. A. White. 1884. 36 pp., 9 pis. (Out of stock.) 

B 10. Cambrian faunas of North America; preliminary studies, by C. D. Walcott. 1884. 74 pp., 10 pls. (Out of stock.) 

J3 11. Quaternary and recent Mollusca of the Great Basin, with descriptions of new forms, by R. Ellsworth Call. Intro· 

duced by a sketch of the Quaternary lakes of the Great Basin, by G. K. Gilbert. 1884. 66 pp., 6 pis. 

B. 15. Mesozoic and Cenozoic paleontology of California, by C. A. White. 1885. 33 pp. (Out of stock.) 

B 16. Higher Devonian faunas of Ontario County, New York, by J. :Vl. Clarke. 1885. 86 pp., 3 pls. 

B 18. Marine Eocene, fresh-water Miocene, and other fossil Mollusca of western North America, by C. A. White. 1885. 26 

pp., 3 pis. 

B 19. Notes on the stratigraphy of California, by G. F. Becker. 1885. 28 pp. (Out of stock.) 

B 22. New Cretaceous fossils from California, by C. A. White. 1885. 25 pp., 5 pis. (Out of stock.) 

B 24. List of marine :Mollusca, comprising the Quaternary fossils and Recent forms from American localities between 

Cape Hatteras and Cape Roque, including the Bermudas, by W. H. Dall. 1885. 336 pp. 

B 29. Fresh-water invertebrates of the North American Jurassic, by C. A. White. 41 pp., 4 pis. 

B 30. Second contribution to the studies on the Cambrian faunas of North America, by C. D. Walcott. 1886. 369 pp., 33 

pis. (Out of stock.) 

B 31. Systematic review of our present knowledge of fossil insects, including myriapods and arachnids, by S. H. Scudder. 

1886. 128 pp. 

B 34. Relation of the Laramie molluscan fauna to that of the succeeding fresh-water Eocene and other groups, by C. A. 

White. 1886. 54 pp., 5 pis. 

B 37. Types of the Laramie flora, by L. F. Ward. 1887. 354 pp., 57 pis. 

B 41. Fossil faunas of the Upper Devonian-the Genesee section, New York, by H. S. Williams. 1887. 121 pp., 4 pis. (Out 

of stock.) 
II SERIES LIST. 

B 13. Tertiary and Cretaceous strata of the Tuscaloosa, Tombigbee, and Alabama rivers, by E. A. Smith and L. C. Johnson. 

1887. 189 pp., 21 pis. 

B 51. Invertebrate fossils from the Pacific coast, by C. A. White. 1889. 102 pp., 14 pis. (Out of stock.) 

B 56. Fossil wood and lignite of the Potomac formation, by F. H. Knowlton. 1889. 72 pp., 7 pis. 

B 63. Bibliography of Paleozoic Crustacea from 1698 to 1889, including a list of North American species, and a systematic 

arrangement of genera, by A. W. Vogdes. 1890. 177 pp. 

B 69. Classed and annotated bibliography of fossil insects, by S. H. Scudder. 1890. 101 pp. 

B 71. Index to known fossil insects of the world, including myriapods and arachnids, by S. H. Scudder. 1891. 744 pp. 

B 77. The Texan Permian and its Mesozoic types of fossils, by C. A. White. 1891. 51 pp., 4 pls. 

B 80. Correlation papers-Devonian and Carboniferous, by H. S. Williams. 1891. 279 pp. (Out of stock.) 

B 81. Correlation papers-Cambrian, by C. D. Walcott. 1891. 447 pp., 3 pls, (Out of stock.) 

B 82. Correlation papers-Cretaceous, by C. A. White.' 1891. 273 pp., 3 pls. (Out of stock.) 

B 83. Correlatioc papers-Eocene, by W. B. Clark. 1891. 173 pp. , 2 pls. 

B 84. Correlation papers-Neocene, by W. H. Dall and G. D. Harris. 1892. 349 pp., 3 pl!'. (Out of stock.) 

B 85. Correlation papers-The Newark system, by I. C. Russell. 1892. 344 pp., 13 pis. (Out of stock. ) 

B 86. Correlation papers-Archea n and Algonkian, by C. R. VanHise. 1892. 549 pp., 12 pis. (Out of stock.) 

B 87. Synopsis of American fossil Brachiopoda, including bibliography and synonymy, by Charles Schuchert. 1897. 

464 pp. 

B 88. Cretaceous foraminifera of New Jersey, by R. M. Bagg, jr. 1898. 89 pp., 6 pls. 

B 93. Some insects of special interest from Florissant, Colo., and other points in the Tertiaries of Colorado and Utah, by 

S. H . Scudder. 1892. 35 pp., 3 pis. (Out of stock.) 

B 97. Mesozoic Echinodermata of the United States, by W. B. Clark. 1893. 207 pp., 50 pls. 

B 98. Flora of the outlying Carboniferous basins of southwestern Missouri, by David White. 1893. 139 pp., 5 pis. 

B 101. Insect fauna of the Rhode Island coal field, by S. H. Scudder. 1893. 27 pp., 2 pis. 

B 102. Catalogue and biqliography of North American Mesozoic Inve~tebrata, by C. B. Boyle. 1893. 315 pp. 

B 105. The Laramie and the overlying Livingston formation in Montana, by W. H. Weed, with report on flora, by F . H. 

Knowlton. 1893. 68 pp., 6 pls. 

B 106. Colorado formation and its invertebrate fauna, by T. W. Stanton. 1893. 288 pp.,45 pls. (Out of stock.) 

B 110. Paleozoic section in the vicinity of Three Forks, Mont., by A. C. Peale. 1893. 56 pp., 6 pls. 

B 120. Devonian system of eastern Pennsylvania and New York, by C. S. Prosser: 1895. 81 pp., 2 pls. (Out of stock.) 

B 121. Bibliography of North American paleontology, by C. R. Keyes. 1894. 251 pp. 

B 124. Revision of North American fossil cockroaches, by S. H. Scudder. 1895. 176 pp., 12 pls. 

B 128. Bear River formation audits characteristic fauna, by C. A. White. 1895. 108 pp., 11 pls. 

B 133. Contributions to the Cretaceous -paleontology of the Pacific coast: The fauna of the Knoxville beds,_ by T. W. 

Stanton. 1895. 132 pp., 20 pis. 

B 134. Cambrian rocks of Pennsylvania, by C. D. Walcott. 1896. 43 pp., 15 pis. 

B 141. Eocene deposits of the middle Atlantic slope in Delaware, Maryland, and Virginia, by W. B. Clark. 1896. 167 pp., 

40 pls. 

B 142. Brief contribution to the geology and paleontology of northwestern Louisiana, by T. W. Vaughan. 1896. 65 pp. 4 pis. 

B 145. Potomac formation in Virginia, by W. M. Fontaine. 1896. 149 pp., 2 pis. 

B 151. Lower Cretaceous gryphreas of the Texas region, by R. T. Hill and T. W. Vaughan. 1898. 139 pp., 35 pis. 

B 152. Catalogue of Cretaceous and Tertiary plants of North America, by F. H. Knowlton. 1898. 247 pp. 

B 153. Bibliographic index of North American Carboniferous invertebrates, by Stuart Weller. 1898. 653 pp. 

B 163. Flora of the Montana fQrmation, by F. H. Knowlton. 1900. 118 pp., 19 pis. 

B 173. Synopsis of American fossil Bryozoa, including bibliography and synonymy, by J. M. Nickles and R. S. Bassler. 

1900. 663 pp. 

B 179. Bibliography and catalogue of fossil Vertebrata of North America, by 0 . P. Hay. 1902. 868 pp. 

B 191. .North American geologic formation names: Bibliography, synonymy, and distribution, by F. B. Weeks. 190'2. 448pp. 

B 195. Structural detai.Js in the Green Mountain region and in eastern New York (second paper), by T. Nelson Dale. 1902. 

22 pp., 4 pis. 

B 204. Fossil flora of the John Day basin, Oregon, by F. H. Knowlton. 1902. 153 pp., 17 pis. 

B 205. The Mollusca of the Buda limestone, by G. B. Shattuck, with an appendix on the corals of the Buda limestone, by 

T. W. Vaughan. · 1903. 94 pp., 27 pis. 

B 206: A study of the fauna-of the Hamilton formation of the Cayuga Lake section in central New York, by H. F. Cleland, 

1903. 112 pp., 5 pls. 

B 210. The correlation of geological faunas; a contribution to Devonian paleontology, by H. S. Williams. 1903. 147 pp.,l pl. 

B 211. Stratigraphy and paleontology of the Upper Carboniferous rocks of the Kansas section, by G.l. Adams, G. H. Girty, 

and David White. 1903. 123 pp., 4 pis. 

PP16. Carboniferous formations and faunas of Colorado, by G. H. Girty. 1903. 546 pp., 10 pis. 

PP19. Contributions to the geology of Washington, by G. 0 . Smith and Bailey Willis. 1903. 101 pp., 20 pis. 

PP21. The geology and ore deposits of the Bisbee quadrangle, Arizona, by F. L. Ransome. 1904. i68 pp., 29 pis. 

PP 24. Zinc and lead deposits of northern Arkansas, by G. I. Adams, assisted by A. H. Purdue and E. F. Burchard, with 

a section on the determination and correlation of formations, by E. 0. Ulrich. 1904. 118 pp., 27 pis. 

PPSl. Preliminary report on the geology of the Arbuckle and Wichita mountains in Indian Territory and Oklahoma, by 

J. A. Taff, with an appendix on the reported ore deposits in the Wichita Mountains, by H. F. Bain. 1904. 97 pp., 

8pls. 

PP 32. Preliminary report on the geology and underground water resources of the central Great Plains, by N.H. Darton. 

1905. 433 pp., 72 pis. 

·" 
SERIES LIST. m 

B 244. Contributions to Devonian paleontology, 1903, by H. S. Williams and E. M. Kindle. 1905. 137 pp., 4 pls. 

PP35. The geology of the Perry basin in southeastern Maine, by G. 0. Smith and David White. 1905. 107 pp., 6 pls. 

PP36. The lead, zinc, and fluorspar deposits of western Kentucky, by E. 0. Ulrich and W. S. T. Smith. 1905. 218pp., 15pls. 

B 257. Geology and paleontology of the Judith River beds, by T. W. Stanton and J. B. Hatcher, with a chapter on the 

fossil plants, by F. H. Knowlton. 1905. 174 pp., 19 pls. 

B 266. Paleontology of the Malone Jurassic formation of Texas, by F. W. Cragin, with stratigraphic notes on Malone 

Mountain and the surrounding region near Sierra Blanca, Texas, by T. W. Stanton. 1905. 172 pp., 29 pls. 

PP 40. The Triassic cephalopod genera of America, by Alpheus Hyatt and J. P. Smith. 1905. 394 pp. , 85 pis. 

B 268. Miocene foraminifera from the Monterey shale of California, with a few species from the Tejon formation, by R. M. 

-Bagg, jr. 1905. 78 pp., 11 pls. 

PP 47. The Tertiary and Quaternary Pectens of California, by Ralph Arnold. 1906. 264 pp., 53 pls. 

Correspondence should be addressed to 

THE DIRECTOR, 

UNITED STATES GEOLOGICAL SURVEY, 

WASHINGTON, D. 0. 

MARUH, 1906. 

0