H. W< Turner — Gold Ores of California. 469 



Forming the crest of the Sierra Nevada to the east of Yo- 

 semite valley is a belt of schists of unknown age. Mt. Dana 

 and Mt. Lyell are culminating points of this area of schists, 

 which extends at least twelve miles northwest of Mt. Dana and 

 judging from the reports of the State Mineralogist at least as 

 far south as the Minarets. This schist belt contains deposits 

 of base ores at numerous points. Specimens obtained by the 

 writer from the Tioga district to the northwest of Mt. Dana, 

 and from Mono pass, show that the bulk of the ores are very 

 rich in sulphides and would probably be difficult of reduction. 

 These ores contain gold and silver, cobaltite, and sulphides of 

 antimony, lead, zinc, copper and iron. One specimen of quartz 

 from the Tioga mine shows a notable quantity of pyrrhotite. 



The report of Mr. E. B. Preston* on the silver ores of the 

 Minarets mining district indicate that the ores are very similar 

 to those above described. 



At Mineral King, about fifteen miles southwest of Mount 

 Whitney is a body of Triassic schists enclosed in the granite, 

 and containing some gold quartz veins. At the upper work- 

 ings of the Empire mine there is a small quartz vein in crys- 

 talline limestone. 



Blende and galena occur in the limestone and blende in the 

 quartz. The mines at Mineral King have not proved profit- 

 able, but the district about Tioga and Lundy is a promising 

 one. 



Veins in the Granite. — The greater portion of the higher 

 part of the Sierra Nevada and nearly the entire mass of it to 

 the south of Mariposa county is composed of granite. In 

 this large granite area very few auriferous quartz veins have 

 been found. In many of the smaller areas, however, entirely 

 or partly enclosed in the auriferous slate series, there are 

 numerous veins frequently containing abundant gold. Two of 

 these enclosed granite areas have been extensively exploited, 

 that about West Point in Calaveras county and about Soulsby- 

 ville in Tuolumne county. 



In a general way the ores of the granite districts are very 

 base, and need chlorination to obtain the gold, but this rule is 

 by no means universal. 



The ores of the mines of the Soulsbyville district in many 

 cases contain a galena-like mineral which gives blowpipe re- 

 actions for lead and antimony. Copper and iron sulphurets, 

 magnetic iron pyrite or pyrrhotite, and blende are abundant. 

 The vein of the Black Oak quartz mine is accompanied by a 

 dark, fine grained slaty rock called " slate " by the miners. 

 This in thin section is seen to contain a large amount of 

 fibrous green hornblende in ragged prisms lying at all angles, 



* llth Ann. Rep. State Mineralogist of California, p. 222. 



