TERTIARV FAUNAS OF THE PACIFIC COAST 533 
San Diego; and the Peninsula of Lower California. ‘The Sierra 
Nevada and Sierra Madre and San Bernardino and San Jacinto 
mountains may also be considered in the same class. The region of 
Santa Catalina and San Clemente islands off southern California 
belong to an area about which little is known previous to the Miocene, 
although it is the belief of the writer that they are in a belt of more or 
less persistent uplift. 
The negative elements or areas of persistent subsidence are: Puget 
Sound; the Willamette Valley; the San Joaquin. Valley, and the 
Sacramento Valley to a less degree; central Ventura County; and, 
since the Eocene, the Salinas Valley, and the vicinity of Los Angeles. 
