Evolution of a Coast Range Corridor in California 

 and Its Effect on the Origin and Dispersal 

 of Living Amphibians and Reptiles 



Frank E. Peabody^ and Jay M. Savage 



Department of Zoology. University of California, Los 

 Angeles and Department of Biology, University of 

 Southern California, Los Angeles 



1 hirty years ago, A. B. Howell wrote (1927, 

 p. 18) that "the fauna of the Pacific Coast of the United States 

 is of unusual interest, and presents many fascinating problems." 

 After three decades of intensive study, Howell's statement is no less 

 true, and many fascinating problems remain for the solving. How- 

 ever, in three decades there has accumulated a great mass of infor- 

 mation on the terrestrial fauna and flora of far western North Amer- 

 ica. Numerous investigators approaching the region from the varied 

 point of view of the zoologist, botanist, paleontologist, and geologist 

 have worked to a large degree independently. Perhaps the time is 

 right for significant syntheses culled from the data of biological 

 and physical disciplines. 



Obviously, any synthesis must draw on the data of geology and 

 paleontology as well as on that from the modern biota. A most 

 important contribution of geology is that our western region is in 

 the throes of violent physical revolution in marked contrast with 

 long antecedent epochs of quiescence. Our modern biota exists in 

 what we and many others regard as an interglacial stage of the 

 Pleistocene epoch. A most important contribution of paleontology 

 is the clear evidence of marked southerly shifts of isotherms on a 

 continental scale culminating in the Pleistocene and integrated with 

 profound topographic changes affecting vast inland areas. While it 

 may be charged that the biologist has not sufficiently heeded these 



1 Deceased June 27, 1058. 



159 



