100 SOUTHERN CALIFORNIA GEOLOGY 



show a diversified land topography and undoubtedly 

 were once continuous with the mainland. 



SUBMARINE VALLEYS AND FAULT SCARPS 



Three, great, submerged valleys alternate with the 

 ranges of the Catalina Group and are about of equal 

 extent and area to them. There are also several pre- 

 cipitous submarine escarpments suggestive of fault 

 lines, notably those in northwest directions along the 

 east and west sides of the San Clemente and Catalina 

 Islands respectively, and a long one in east and west 

 directions which apparently attends the entire south 

 side of the Catalina Islands. 



Another conspicuous submarine escarpment, from 

 2500 to 3000 feet high, borders the south side of the 

 Anacapa Range, and is continued to the south by the 

 south-front fault escarpment of the Santa Monica 

 Mountains. 



TWO AGES OF SUBMARINE RANGES 



The apparent presence in the configuration of two 

 prevalent trends to the northwest and east-west re- 

 spectively, together with certain facts of the ge- 

 ologic nature which cannot be here presented, sug- 

 gest to us that two mountain-making epochs of Cali- 

 fornia are represented in this configuration. These 

 are : first, those of an older Northwest, or Coast Range 

 System, and second, those of the East-West, or Trans- 

 verse Belt. Northwest f aultings of still later age have 

 probably crossed both of these systems. There is still 

 much to be learned. 



The Catalina Group may have been the former 

 southern extension of the west side of the older or 



