GEOLOGV, 47 



CHAPTER III. 

 GEOLOGY. 



§ 34. General Geological Character. — California, geologi- 

 cally considered, belongs chiefly to the paleozoic and tertiary 

 epochs. The carboniferous rocks are wanting, or then* exist- 

 ence in the state is confined t,o a very small district, and has 

 not been demonstrated even there. A tertiary sandstone, some 

 of which is metamorphic, having lost its original stratification 

 under the influence of intense heat, underlies the valleys of the 

 Sacramento, the San Joaquin, and the coast, and is seen in the 

 Coast Mountains, the Great Basin, and the Colorado Desert. 

 Granite occupies the higher portions of all the mountainous 

 districts, and considerable portions of the Great Basin and the 

 borders of the Colorado Desert, The scarcity of stratified 

 rocks is plainly discoverable by the traveller in the number 

 and ruggedness of the mountains; only primary, eruptive, and 

 metamorphic rocks make such steep hill-sides. The thinly- 

 stratified rocks, with intervening layers of clay, are soon worn 

 down by the water mto gentle slopes, and covered with fertile 

 soil, every foot of which may be turned over by the plough, 

 and with profit. Such is not the character of California, nearly 

 all of which is primary or metamorphic. 



Many rocks besides granite and tertiary sandstone appear 

 in irregularly-distributed patches. About Mounts Shasta and 

 Las^jon, Castle Peak, the Marysville Bnttes, in the plateau of 

 the Sierra Xevada, tlie Great Basin, and the Colorado Desert, 

 there are considei-able tracts of basalt, lava, trap, and trachyte; 

 and in other places there are small tracts. Some very remark- 

 able hills of basalt, cnlled "Table MouTitainB," are found in the 



