126 RESOURCES OF CALIFORNIA. 



Mount St. Helena, in the first of those counties, the Geysers 

 in the second, and Clear Lake in the third, all of volcanic ori- 

 gin, and at least two of them the craters of great volcanoes, 

 are the three corners of a triangle, with sjdes thirty miles 

 long, and an area that was once alive with subterranean fires. 

 The basaltic columns in regular crystallization, found near the 

 summit of St. Helena, extensive strata of trap covering the 

 adjacent ridges, the tufa formed by torrents of mud or wet 

 sand, that came from volcanic vents on the triangle, making 

 up considerable parts of the ridges between Suisun and Napa, 

 and between Napa and Sonoma Valleys, the petrified forests 

 near Calistoga, the sulphur bank and the borax pond near 

 Clear Lake, all indicate the remarkable influences that were 

 active in that region in a remote age. Not unworthy of their 

 associates, are the mineral springs in the same region. We 

 find them hot, warm, and cold ; rich in sulphur, iron, alum, 

 Epsom salts, carbonates, chlorides, and borates of soda, car- 

 bonic acid, sulphuretted hydrogen, carburetted hydrogen, and 

 other gases. 



The following analytical table gives the number of grains 

 of the different solids contained in a gallon of certain mineral 

 waters of California. The analysis of Napa Soda was made 

 by L. Lanzweert ; those of the White Sulphur water by Prof. 

 John Le Conte ; that of Sanel by Dr. J. A. Bauer ; that of 

 Adams by Thomas Price ; and the others by unknown authori- 

 ties. 



