45 RESOURCES OF CALlFORIiriA. 



Sierra Nevada, The largest of these is in Tuolumne county, 

 about three thousand feet above the sea, and one hundred 

 miles eastward from San Francisco. It is thirty miles long, 

 three hundred to eight hundred feet high above the surround- 

 ing country, and about a quarter of a mile wide, in many places 

 less. The basaltic formation is evident at a distance, from the 

 perpendicularity of the sides near the top, and the flatness of 

 its summit, gently descending toward the west. Along the 

 sides of the Sierra Nevada, near the line of separation between 

 the sandstone of the valley and the granite of the higher parts 

 of the Sierra, are found various other rocks, among which 

 slate, quartz, and limestone, are prominent. The slates are 

 usually soft, their cleavage often perpendicular to the horizon. 

 Limestone is abundant about two thousand feet above the sea, 

 between latitudes 37° 30' and 39°. It is all metamorphic, and 

 some of it is a fine marble, which may prove of value for stat- 

 uary. Most of it is gray in color. Metamorphic limestone is 

 also found near Santa Cruz, near New Almaden, at Monte 

 Diablo, and in Shasta and Siskiyou counties. It is said that 

 some stratified secondary limestone has been found in Shasta 

 county, but this is a matter of doubt. No secondary coal has 

 been found in tlie state. Tertiary coal, much of it a lignite, 

 has been found at various places in San Diego, Santa Clara, 

 Alameda, San Francisco, San Mateo, Contra Costa, and So- 

 noma counties, and much money has been spent in opening 

 veins. 



§ 35. Diluvium. — The Sacramento and San Joaquin valleys 

 are covered with a diluvium from four hundred to fifteen hun- 

 dred feet deep. It is composed of alternate layers of sand, 

 gravel, and clay. The most complete information w^hich we 

 have as to the nature of this diluvium is given in the report 

 of the boring of an artesian well, one thousand feet deep, at 

 Stockton. This is, I believe, the only artesian well in the Sac- 

 ramento Basin ; at least, it is the most notable one. An at- 

 tempt was made to bore an artesian well in Sacramento, but 

 the auger struck a stratum of boulders about four hundred feet 



