GEOLOGY. 61 



Wood and water are very scarce. Little is known about the 

 district as vet. The Coso and the Esmerelda districts are both 

 in the Great Basin of Utah, and about five thousand feet above 

 the level of the sea. 



It is said that rich silver-mines have been discovered in the 

 valley of the Mojave River. 



In the Coast Mountains, in Monterey county, a silver-inine 

 called Allisal has long been known to exist, but it is not rich 

 enough to pay. Similar veins are found in the Coast Moun- 

 tains, in Santa Cruz county. 



Veins of silver ore are also found in Xevada county. 



§ 41. Plati7iurn. — Platinum, iridium, and osmium, are three 

 white metals resembling steel, often found in the placer mines 

 of Cahfornia. Thev usuallv occur toirether : and are found 

 more abundantly in the lower part of the Klamath valley than 

 in any other part of the state. In many districts they are 

 entirely lacking. Platinum is found in lumps by itself; iridi- 

 um and osmium are found united, and are then called irid- 

 osmium. These metals are found in small particles, usually 

 fine scales ; the largest piece was of irid-osmium, found on the 

 Lower Elamath, and weighed an ounce and a quarter. They 

 are not found separate from the gold, nor are they ever the 

 main object of search ; they are obtained in small quantities 

 only, and are rarely bought and sold in the state ; they have 

 no fixed market price. When mixed with gold-dust, they 

 injure its value, and prevent its reception at the mint on de- 

 posit. 



§ 42. Quicksilver. — There is probably no country in the 

 world so rich in quicksilver as California. That metal is ob- 

 tained only from its sulphuret or cinnabar, of which extensive 

 deposits are found in Santa Clara county, about sixty miles 

 southward from San Francisco, and fifteen miles from San 

 Jose. There are three mines here — the Xew Almaden, the 

 Euriqueta, and the Guadalupe. The ore is found between trap 

 on one side, and metamorphic limestone on the other. The 

 mines are about one thousand feet above the level of the sea. 



