Mountains of the South 



239 



the north slope Snow Creek, which descends to the San Gor- 

 gonio Pass, falls 4,000 feet in one mile of its course. On the 

 northeast side of the mountains the slope falls 2,500 feet in as 

 many feet of horizontal distance. Torrential streams descend- 

 ing from the high peaks have notched deep narrow canyons in 

 the mountain sides, and these have precipitous walls and are 

 separated by narrow ridges giving to the mountain side an ex- 

 ceedingly rugged slope. The southwest side of the mountains 



Photo by W. S. W. Kew, U. S. Geol. Survey 



FIG. 72. Massive Conglomerate, Sandstone and Shale, in Escondido Can- 

 yon, Los Angeles County. Picturesque outcrops north of Soledad Canyon. 



is less precipitous. It is outlined by the zone of faulting of the 

 San Jacinto fault, which is considered to be a branch of the San 

 Andreas fault which passes through San Gorgonio Pass on the 

 north, the two meeting in Cajon Pass 3 miles to the northwest. 



The San Jacinto Range a Vast 

 Uplifted and Tilted Block 



The San Jacinto Range is a triangular block having a north- 

 west southeast trend. It is bounded on the three sides by fault 

 zones, the San Jacinto on the southwest side 35 miles in length; 

 the San Andreas on the north, 25 miles, along which lies the 



