530 RALPH ARNOLD 
DIASTROPHISM IN THE QUATERNARY 
Important and more or 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. 
FAUNAS 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 
t Mem. Cal. Acad. Sct., Vol. III, 1903, pp. 53-55. 
2 Ann. and Mag. Nat. Hist., 3d Ser., Vol. XVII, 1866, p. 275. 
