364 Adventures in Scenery 



sion of molten granitic magma metamorphosed the shales and 

 sandstones to schists and quartzites. The escarpment of the 

 great ridge stands out boldly because the upheaved rocks are 

 hard and withstand erosion. 



Turning south in Sierra Pelona Valley, two or three miles 

 east of Oaks, and going down Agua Dulce Canyon, the famed 

 Vaquez Rocks are at the left. In Escondido Canyon promi- 

 nent outcrops of red-hued conglomerates and sandstones, with 

 intercalated greenish shales, have been carved by erosion into 

 fantastic forms which give a weird and mysterious aspect to the 

 region. 



From Sierra Pelona Valley the highway passes through a 

 gap in the hills, at an elevation of 3,423 feet, into the valley in 

 which Acton is located, and thence up the valley to Vincent, 

 at the summit of the divide between the Santa Clara River and 

 the gulch that leads to the Mojave Desert. At the bottom of 

 this gulch is the zone of crushed, broken and folded rocks which 

 marks the great San Andreas fault, and this in turn marks the 

 southwest boundary of Mojave Desert. 



Palmdale, 72 miles from Los Angeles (El. 2,669 feet) ; 

 Lancaster, 80 miles (El. 2,356 feet); Mojave, 104 miles (El. 

 2,733 feet). 



Crushed and Broken Rock. Marks 

 San Andreas Fault 



The succession of valleys and ridges or other features that 

 indicate the fault zone can be traced northwestward and north- 

 ward to San Francisco and beyond, and southeastward through 

 Cajon Pass and San Gorgonio Pass to the Salton Sea Basin. This 

 long zone of faulting is known as the San Andreas rift. Sev- 

 eral of these valleys stand out prominently. A notable one is 

 Leonis Valley, in which is Amargosa Creek, west of Palmdale. 

 Harold Reservoir, west of the highway, is in one of these val- 

 leys. Water from Little Rock Creek, to the east, is stored in 

 this reservoir for the Palmdale irrigation district. This is the 



