136 SOUTHERN CALIFORNIA GEOLOGY 



however, to authoritatively discuss the geology of 

 Northern California. 



NORTHWEST STRUCTURE OF THE CATALINA 

 GROUP 



While the Coast Range structure proper abruptly 

 ends as a physiographic feature at the north side of 

 the Transverse Belt, there is much reason to believe 

 that its structrual affinities may be found to the south- 

 ward in the northwest trending Catalina ridges and 

 troughs of the submerged Continental Shelf. 



Analyses of the submarine contours of the Contin- 

 ental Shelf show that the troughs and ranges there 

 are divisible into two groups of opposite trends, which 

 are probably coincident with ancient directions of 

 folding or faulting. The first of these, of northwest 

 direction, we have termed the Catalina group; and 

 the second, of east-west direction, the Anacapa group. 



The Catalina group of trends, so far as is indicated 

 by the still imprefect maps of the submarine contours, 

 consists of alternating ranges and valleys suggestively 

 like those of the adjacent mainland. 



The position and trends of the Catalina portion of 

 the shelf, although situated slightly west of a south- 

 ward projection of the Coast Ranges, strongly sug- 

 gests a relationship between the two rejgions, the 

 continuity of which has been broken by the develop- 

 ment of the east-west structures of the Anacapa Island 

 group and a later subsidence of the Catalina group. 



STRUCTURE FEATURES OF THE GREAT 

 TRANSVERSE BELT 

 No more interesting geologic features exist in 

 in California than the faults and folds of the great 



