UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 8, No. 10, pp. 243-256, pis. 24-25 Issued November 13, 1914 



THE AGASOMA-LIKE GASTROPODS OF THE 

 CALIFORNIA TERTIARY 



BY 



WALTER A. ENGLISH 



CONTENTS 



PAGE 



Introduction 243 



Table of Geologic Ranges 244 



Descriptions of Genera 244 



Ficus 244 



Trophosycon 245 



Agasoma 245 



Descriptions of Species 245 



Ficus mamillatus Gabb 245 



Ficus modestus (Conrad) 246 



Ficus pyriformis Gabb 246 



Ficus rodeoensis, n. sp 246 



Trophosycon nodiferum (Gabb) 247 



Trophosycon kernianum Cooper 248 



Trophosycon stanfordense (Arnold) 249 



Trophosycon elallamens'e (Weaver) 250 



Trophosycon oregonense (Conrad) 250 



Agasoma sinuatum Gabb 250 



Agasoma gravidum (Gabb) 251 



Agasoma barkerianum Cooper 252 



Agasoma barkerianum Cooper, var. santacruzanum Arnold 252 



Agasoma barkerianum Cooper, var. elarki, n. var 253 



. INTRODUCTION 



The species of gastropods commonly included in the genera Ficus 

 and Agasoma have a restricted vertical range and a fairly wide geo- 

 graphical distribution in the California Tertiary foi'mations. and hence 

 have come to be important guide-fossils in palaeontologic and geologic 

 work. As there is some confusion in the literature relating to these 

 forms, the writer has undertaken to review them in order to increase 



