COAST RANGE CORRIDOR IN CALIFORNIA 



183 



al)lc to judge the relative age of west and east arms of dispersals 

 reaching southern California via the corridor and the Sierran or 

 Inland route. At least In the four examples of sympatry cited, It is 

 fairly certain that the dispersals down the corridor are the "new-- 

 comers" to southern California. The evidence of corridor evolution, 

 together with relative development of insular populations and 



^=^-. y- 



35' 



BRIDGE 



SYMPATRIC 

 POTENTIAL 



Fig. 19. Map showing probable migration paths taken by modern 

 amphibians and reptiles with respect to the Coast Range corridor and 

 associated geographic features. 



development of post-Pleistocene fragmentation of patterns of 

 distribution are keys to relative age determination. 



Coastal Islands and "Waif" Faunas 



Distribution of the far western herpetofauna on offshore islands of 

 southern California (Stebbins, 1954) suggests that it may be profit- 

 able to reexamine the established theory that the offshore Islands 

 have been connected with the mainland at one time or another 

 during the late Pleistocene. Among the amphibians, only Bairacho- 

 seps, Aneides luguhris, and Hyla regilla have reached offshore Islands. 



