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University of California Publications in Geology [Vol. 8 



their value for correlation purposes. The generic classification of the 

 species considered has been changed from time to time; the Tropho- 

 sycons were put in the genus Ficus by Gabb and Dall, while Cooper 

 and Arnold considered them a sub-genus of Agasoma. 



Table Showing Geologic Eange of Ficus, Trophosycon and Agasoma 



Family Doliidae 



Geuus Ficus 



Ficus mamillatus Gabb 

 Ficus modestus (Conrad) 

 Ficus pyriformis Gabb 

 Ficus rodeoensis, n. sp. 



Genus Trophosycon 



Trophosycon nodiferuni (Gabb) 

 Trophosycon kernianum Cooper 

 Trophosycon stanfordense (Arnold) 

 Trophosycon clallamense (Weaver) 

 Trophosycon oregonense (Conrad) 

 Family Buceinidae 



Genus Agasoma 



Agasoma sinuafrum Gabb 

 Agasoma gravidum (Gabb) 

 Agasoma barkerianum < looper 

 Agasoma barkerianum Cooper, var. 



sa ntacr uzan u m Arnold 

 Agasoma barkerianum Cooper, var. 

 clarki, n. var. 



Tejon 

 X 



"Vaque 

 ros"V 



X 



Miocene 



Monterey 

 :- anrl San 

 "Temblor" Pablo 



Plio- 

 cene 



Pleis- 

 tocene 



Fernando group 

 Lower Upper 

 X X 



Genus FICUS Bolten 



The genus Ficus is represented among living shells by six species, 

 all of tropical distribution. One of them, Ficus decussatus, occurs on 

 the west coast of North America south of Lower California. They 

 are all characterized by very thin shell; large body-whorl; nearly 

 enveloped early whorls; wide, shallow, straight canal; and cancellated 

 surface. Although the animal is similar to the living Dolium, the 

 shell is not particularly close to other members of the Doliidae. Among 

 fossils, Ficus mamillatus from the Eocene is the oldest species referred 

 to this genus. Ficus pyriformis from the lower part of the Monterey 

 group is distinctly a Ficus, and resembles the living Ficus dussumieri. 

 The type specimen of Ficus rodeoensis, from the upper part of the 

 Monterey group, is a cast and lacks the characteristic ornamentation, 

 but is ficoid in shape. 



