Vol. IX] SMITH— CLIMATIC RELATIONS 129 



Derivation of Tertiary Marine Faunas of California. 



The marine faunas of Tertiary and Recent time on the coast 

 of California must be either endemic or immigrants. There are 

 certain persistent stocks that appear to give us a continuous 

 line from Eocene time, but the great majority are unmistake- 

 ably immigrants. The regions from which they may have 

 come are so limited in number and so characteristic in their 

 faunas that it is comparatively easy to determine the kinship 

 and probable origin of the successive faunas in the California 

 province. 



The Martinez Eocene has strong Oriental affinities, shown 

 in: Ovula, Xenophora, and the Tudicla group. The Tejon 

 Eocene, while having some Oriental survivors, such as Rimella, 

 Terebellum and the Tudiela group, is clearly Caribbean in kin- 

 ship, in proof of which may be cited the Venericardia planicosta 

 fauna, which came in from the Atlantic region through the 

 Panama portal. 



The Oligocene is decidedly Oriental, as shown by the in- 

 coming of Valuta (Miopleionia) , Dolium, and Japanese types 

 of Nucula. The incoming of these forms is accompanied by 

 the advent of northern species: Thyasira bisecta, Phacoides 

 acutilineatiis, Solemya, and Turcicula. 



The lower Miocene Vaqueros fauna retains some Oriental 

 survivors, such as Rapana, but is, in the main, Caribbean in 

 kinship. The Lyropecten group is the most characteristic 

 Caribbean element, having been present in that region already 

 in Oligocene, and wholly lacking on the Pacific coast in that 

 epoch, 



R. E. Dickerson* has shown that in lower Miocene time 

 there was probably a connection between the Caribbean and 

 the Pacific. This is borne out not only by the occurrence of 

 Lyropecten, but also by Dosinia and the giant oysters. 



In the Temblor epoch of the lower Miocene there is no 

 further suggestion of Caribbean immigration, although Lyro- 

 pecten is still exceedingly abundant. There is, however, a 

 suggestion of renewed Oriental immigration in the Pecten 

 groups. Pallium and Amusium. 



The upper Miocene faunas appear to be endemic, or descend- 

 ants of those that preceded them, the only outside increments 



* Proc. Calif. Acad. Sci., 4th ser., vol. 7, p. 197, et seq. 



