COAST RANGE CORRIDOR IN CALIFORNIA 



177 



the possibility that the subspecies in the corridor came in from the 

 North in the Pleistocene at a time when the marine barrier existed 

 at the south end of the present corridor. In any case the coincident 

 insular and mainland distribution suggests a certain antiquity of 

 subspecific differentiation. It would be interesting to know the rela- 



•-■4 FOOTHILL 

 ALLIGATOR 

 LIZARD 



rcriMcirA. ,nAiGERRHONOTUS 

 rSCINCICAUDAS mULTICARINATUS 



35' 



'ANCESTRAL SPECIES 

 SONORAN ALLIGATOR 

 LIZARD 



Fig. 14. Distribution of foothill alligator lizard, Gerrhonotus multi- 

 carinatus, and its relationship to range of Gerrhonotus kingi, Sonoran 

 alligator lizard. Eastern species is more closely allied to G. muUicarinatiis 

 than to G. coeruleus, and the last two forms occur sympatrically in many 

 regions. 



tive degree of differentiation between webbii and midticarinatus on 

 the south and north ends of the San Joaquin Valley. 



In summary: Relations of A^Iadro-Tertiary species to the corridor 

 and adjacent land features appear more varied than for Arcto- 

 Tertiary species. Northern elements of the Madro-Tertiary moved 

 around the north end of the Great Valley and down the corridor; 

 southern elements moved up the corridor, or if xeric in habitat 

 preference, met an effective barrier at the Transverse Ranges and 



