Vol. IV] ANDERSON AND MARTIN— NEOCENE RECORD 33 



or percentage of subtropical species. This epoch of 

 subsidence did not terminate entirely until the final 

 uplift that closed the occupation of the basin to marine 

 conditions. 



8. Uplift that expelled the sea from almost the 

 entire basin, and left it under oscillating conditions 

 only in the deeper portions of the same. This inter- 

 val of uplift and oscillation developed the subgroup 

 of upper Etchegoin strata which contains an alter- 

 nating series of marine and freshwater sediments 

 and faunas in the deeper portions of the Great Valley. 

 ' 9. Differential local uplifts that expelled the sea 

 entirely from the basin but impounded and retained 

 an extensive body of freshwater within the Great 

 Valley, in which were subsequently developed the 

 series of sediments known as the Tulare group. The 

 Tulare should probably be correlated in time with the 

 marine Merced group which is well developed about 

 the seaward outlets of the Temblor basin and in other 

 similar situations along the coast. 



10. The general, or continental, uplift that 

 brought the final close of the Neocene and initiated 

 the Pleistocene and its widespread terrestrial condi- 

 tions. 



Conclusions. — It is a well-known fact that the development 

 of the Neocene in central California, where its largest area 

 exists, is very great, at several places being not less than 6000 

 feet in thickness. It is evident that this basin should therefore 

 be regarded as containing the most representative section of 

 these rocks in California. 



For purposes of intensive study this enormous aggregate of 

 strata should be divided into as many groups and divisions as 

 the geological facts in the case will sustain. The facts of prime 

 importance bearing upon this problem are those connected 

 with the physical and dynamic history of the period. The first 

 object to attain in its solution is the clear understanding of its 

 diastrophic record. 



That there is considerable complexity in the diastrophic 

 record of the Neocene in its most representative areas is evi- 

 dent to any one familiar with the literature and with the facts 



