TERTIARY FAUNAS OF THE PACIFIC COAST 247 



DIASTROPHISM IN THE QUATERNARY 



Important and more 9r less widespread periods of diastrophism 

 later than the one terminating the Monterey (middle Miocene) 

 period of deposition occur in the Pleistocene. Up to the time of the 

 discovery of certain indisputable evidence' regarding the Pleistocene 

 age of beds affected by certain of these latest mountain-forming 

 movements, the diastrophism had been considered as closing the 

 Pliocene and initiating the Pleistocene. Minor movements produ- 

 cing local unconformities took place in central and southern Cali- 

 fornia at various times during the Pleistocene in addition to the more 

 far-reaching disturbances in the same epoch. The latest diastrophism, 

 including the elevations and subsidences of the coast line, the recent 

 movements along the earthquake rift, etc., are familiar to all. The 

 localization of many of these movements is known already; the locali- 

 zation of many more of them will, it is believed, become clear when 

 they are studied in detail. 



FAITNAS AND CLIMATE OF THE PLIOCENE AND PLEISTOCENE 



The faunas of the Pliocene and Pleistocene freshwater deposits 

 are closely related and in some cases almost identical to the living 

 faunas of the same province, while the marine faunas, on the other 

 hand, indicate profound variation of environment, at least as regards 

 temperature. Dr. Philip P. Carpenter^ was the first to point out the 

 cold-water faunas of the upper Pliocene and lower Pleistocene of the 

 Pacific Coast. His conclusions have been strengthened by later 

 workers, and in addition it has been shown that the latest Pleistocene 

 faunas of the same region are of a type more tropical than those now 

 inhabiting the shores of the Pacific Coast of the United States. It is 

 thus evident that the warm temperature of the upper Miocene gave 

 place to cooler conditions just before or at the beginning of the lower 

 Pliocene, and to sub-boreal conditions in the upper Pliocene and 

 lower Pleistocene. The later Pleistocene showed a very marked 

 increase in oceanic temperature over the lower Pleistocene, even 

 approaching subtropical warmth, and this, in turn, being followed 

 by the conditions now prevailing. At some time during the upper 



' Mem. Cal. Acad. Sci., Vol. Ill, 1903, pp. 53-55. 



2 Ann. and Mag. Nat. Hist., 3d Ser., Vol. XVII, 1866, p. 275. 



