410 University of California Publications in Geology [Vol. 13 



A quartz vein just below Monarch Flat has been prospected for 

 ore. A specimen from the dump consists of an almost solid mass of 

 pyrrhotite and galena in equal amounts with smaller quantities of 

 pyrite and chalcopyrite. 



Greenlead Camp was once a prosperous mining camp, but it is 

 now abandoned. Gold was mined from deposits along the limestone- 

 granite contact, where it was found in quartz veins with pyrite, chal- 

 copyrite, and galena. 



A somewhat different occurrence of gold is found half a mile north- 

 west of Doble, where a quartz vein over forty feet thick cuts the 

 Saragossa quartzite. All through the vein there is slickensiding 

 parallel to the dip which is 54° SW, the strike being N 40° W. The 

 quartz contains limonite, some of which is in the form of cubes, evi- 

 dently pseudomorphic after pyrite. The ore is free-milling and runs 

 about $3 per ton, but the quantity is limited by a low-dipping fault 

 which cuts off the vein about fifty feet below its outcrop on the sum- 

 mit of the small hill. 



The Rose Mine is in the Furnace limestone, which at this locality 

 is nearly vertical and is cut by dikes of fine granitic rock containing 

 quartz, biotite, and a feldspar so decomposed as to be indeterminable. 

 These dikes vary in thickness from less than a foot to more than 

 twenty feet (pi. 23B), and the adjacent limestone is often pure white 

 and coarsely crystalline, individual crystals being a centimeter long. 

 The ore occurs as veins and irregular discontinuous bodies following 

 the general trend of the dikes sometimes wholly within and more 

 often without, but never far from the contact. The minerals in the 

 ore bodies are quartz, pyrite, chalcopyrite, cuprite, azurite, malachite, 

 galena, hematite, and gold. The value is gold, which often occurs as 

 beautiful delicate moss and fernlike masses in cavities in the quartz. 

 The tailings have recently been reworked and ran from $3 to $4 per 

 ton, thus showing that some of the gold was in too intimate associa- 

 tion, probably with the pyrite, to be entirely free-milling. The mine 

 was sunk to a depth of a thousand feet, but the nature of the lower 

 levels is not known. 



Numerous small tunnels are also found in this vicinity, and it is 

 said that mines were worked here under the Spanish rule. On the 

 southeast side of Round Valley there are about a dozen arrastres now 

 overgrown with brush, and their presence lends support to this state- 

 ment. 



