162 F. E. PEABODY AND J. M. SAVAGE 



from Oregon (Van Frank, 1955) clearly indicate an additional, 

 important conclusion. Before the end of the Miocene epoch the far 

 west possessed a salamander fauna distinct from those of eastern 

 North America and Asia. The fossil record suggests that the antiq- 

 uity of anuran development at the familial and generic levels was 

 similar to that of the urodeles. However, the anuran fauna of western 

 North America has not become as clearly differentiated from the 

 eastern fauna. 



On a worldwide basis the antiquity of families and genera of 

 modern reptiles does not correspond to that of the amphibians, that 

 is, the rate of evolution has been faster. A general impression is that 

 whereas most modern families, for example, the Iguanidae and 

 Varanidae, were evolved before the beginning of the Cenozoic, the 

 majority of modern genera in all families originated in middle to 

 late Cenozoic. In any event, the fossil record has little to offer on 

 the origin of modern genera and families of reptiles in far western 

 North America. 



The fossil record makes little contribution to the origin of modern 

 species of the herpetofauna generally. Our knowledge of specific 

 characteristics of modern skeletons, of representative herpetofaunas, 

 and of stratigraphic controls within the Quaternary epoch is much 

 too deficient. Historical insight of the paleontologist would suggest, 

 however, that in our far western area, physical events culminating 

 in the Pleistocene epoch provided abnormally strong stimuli to the 

 rate of evolution at the level of species and subspecies. 



THE CALIFORNIA COAST RANGE CORRIDOR 



Obviously the above account of purely paleontological contribu- 

 tions to the stated theme of the symposium are disappointing and 

 inadequate. With this fact all too apparent, the writers groped for a 

 more significant contribution in the form of a multi-directional 

 approach — essentially a new look at old data from geology, paleon- . 

 tology, and herpetology. The senior author has long been fascinated 

 by the classic rassenkreis of subspecies of Ensatina as ably described 

 by Stebbins (1949). Reflection on possible historic controls of the 

 sympatric association of Ejtsatina subspecies in southern California 

 suggested that somehow the physical history of California may re- 

 veal the vital causative factor — a possibility not entertained by 



