350 Adventures in Scenery 



west from Arcadia is Pasadena (eight miles) and beyond the 

 Arroyo Seco is the faulted valley of La Canada. The Verdugo 

 Mountains and San Rafael Hills are cut off from San Gabriel 

 Mountain pleateau by faults and the depressed valley of La 

 Canada. 



ROUTE B. SAN BERNARDINO, VIA CAJON PASS AND MOJAVE 

 DESERT TO DEATH VALLEY. 377 MILES 



San Bernardino is on the depressed floor of the valley or 

 basin that lies at the foot of the San Bernardino Mountains. 

 The mountain range has been uplifted about 6,000 feet along 

 the line of fracture of the San Andreas fault. This journey is 

 over a mountain range, from the valley where orange orchards 

 and vineyards flourish, to the desert where the cactus and sage 

 brush grow scantily on the arid soil through which the highway 

 passes. Cajon Canyon is a notch cut in the mountains where 

 the fractured rocks of the San Andreas fault made the rapid 

 erosion of the deep canyon possible. 



Baked Sandstone and Shales 

 in Cajon Canyon 



At the left, as the ascent is made up the canyon, tilted out- 

 cropping strata of metamorphosed sandstones and shales (prob- 

 ably of Palaeozoic age) stand out in grotesque monuments. 

 Cajon Canyon and the San Andreas fault, which runs through 

 it, mark the line of separation between the San Bernardino and 

 San Gabriel mountain ranges. Over the gravelly sandy wash 

 of the lower canyon the highway rises from 1,073 feet at San 

 Bernardino to 4,301 feet at Summit Pass, 18 miles. Mountain 

 rivulets from the summit carry water northward to Mojave 

 River. Arrowhead Lake, on the rim of the mountains near the 

 summit 10 miles east of the highway, is at an elevation of 6,100 

 feet. Its waters drain southward to the Santa Ana River and 

 the Pacific Ocean. Lone Pine Canyon marks the line of the 

 San Andreas fault to the northwest. The elevation of the head 



