176 SO'UTHERN CALIFORNIA GEOLOGY 



tionship with the ranges of San Luis Obispo County of 

 similar trends. On the other hand, the bend may have 

 been an accompaniment of the great budding which I 

 described. To solve such problems will require much 

 field work and study. 



RELATION TO THE GREAT MOUNTAIN PASSES 

 The great gateways into Southern California known 

 as the Tejon, Cajon and San Gorgonio Passes are all 

 located along the line of the San Andreas Rift at posi- 

 tions where it is intersected by faults of other direc- 

 tions. The path of the rift also cuts across many 

 other lines of faulting, especially those of the older 

 east-west belt like the Bouquet and Cucamonga Rifts. 



THE SAN ANDREAS-PUENTE BELT OF 

 FAULTING 



For reasons which will be apparent, I have deferred 

 until now the task of describing a peculiar structural 

 feature which I will term the San Andreas-Puente Belt 

 of faulting. This, in turn, is a portion of a great 

 flexured belt or buckle which has dominated the struc- 

 ture of part of Southern California. It embraces a 

 wide and diversified strip of country one hundred and 

 forty miles long which extends from the "bend" in the 

 San Andreas Rift, at the west end of the Valyermo 

 section the Cajon Pass, and lies between the said 

 rift on the northeast side of the San Gabriel Range 

 and the Puente Fault line on the southwest side 

 of the Puente Range. Between these main bordering 

 faults there are several parallel fault lines, some one of 

 which practically defines a border of the Verdugo, 

 Repetto and Puente Ranges or lies within the area of 

 the San Gabriel Highland. Its width in cross-section 



