CHAPTER XVI 
Geology of the Californias—Boundaries—Lower California-—Moun¬ 
tains—Surface—Deserts—Valleys— Streams—Temperature—Pro¬ 
ductions—Exports—Pearl Fishery--Present condition of Lower 
California. 
The Geology of the Californias.— The feature of the 
Rocky Mountains and the regions lying west of them, most 
interesting to the geologist, is found in the evidences of past 
volcanic action, which are strewn far and wide about the path 
of the traveller wherever he goes. The main ranges, which 
rise from twelve to twenty-seven thousand feet above the level 
of the sea, are chiefly composed of primitive rock, covered with 
eternal snows. Having passed these, the wayfarer westward 
enters a region, parts of which are occupied by plains covered 
with volcanic sands and debris—or piled with mountains of 
fused rock and decomposing lava clothed with forests of 
terebinthine trees, broken often by bold barren tracts of cliffs, 
and overhung here and there by lofty pinnacles of extinct vol¬ 
canoes, towering in freezing sublimity, thousands of feet above 
the line of perpetual frosts—great sentinels in the heavens— 
clad in the shining raiments of everlasting snow. This is a 
general description of the whole territory lying west of the 
Rocky Mountains, and extending from Cape San Lucas to the 
Arctic sea. 
The peninsula of Lower California, extending from Cape 
San Lucas to the Bay of Todos Santos, in Lat. 32° N., on the 
Pacific, and to the mouth of the Colorado, on the Gulf side, 
is a pile of volcanic debris and scorise. Much of the surface 
is still heated by subterranean fires. No craters are in action. 
But hot springs of w r ater and bitumen, and frequent earth- 
43 
