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University of California Publications. [Geology 



rock is in part almost wholly garnet and in part granitic } with 

 small areas of limestone overlain. At the Blue Stone Mine the 

 country rock is an almost entirely altered limestone. It is perhaps 

 more than half epidote, and presents in the hand-specimen a pale 

 greenish gray color. This mass has been more or less fractured 

 and refilled with calcite, in which the ehalcopyrite is imbedded. 

 The ehalcopyrite is usually idiomorphic, at least it usually has 

 one or two well formed faces. The rifts containing the ore betray 

 some parallelism. The mine was named from a deposit of chal- 

 canthite (blue-stone) which occurs near the surface. Farther 

 south on this same ridge is the McConell Copper Mine, where ore 

 occurs mostly as an oxide. Oxidation has probably extended 

 deeper there than any of the places thus far mentioned. Near 

 this mine are several prospects, which usually are near a contact 

 of limestone and granite. The deposits so far mentioned are 

 all in or adjacent to the belt of schist. One reef of schist of a 

 dark color, which is thus in contrast to the rest of the surround- 

 ing schist, crosses the summit transversely. In it there was 

 found disseminated sulphides of copper and iron. The reef was 

 supposed, on account of its strike and width, to be a dyke which 

 had suffered along with the rest of the rocks the dynamic action 

 which produced the schists. Sulphide was also found near the 

 gra no-porphyry where it had been involved in the metamofphic 

 action, but the sulphide did not appear to be so much dissemi- 

 nated as in the case of the dark reef. 



Farther south of the McConell Mine, and off the map PL 1, 

 gold occurs, and it also occurs in the Mason Pass, to the north. 

 There is also mineralization to some extent northeast of the Blue 

 Stone Mine, in the low hills near the west side of the river. East 

 of the river, near the eastern border of the map PI. 1, are several 

 veins of copper. They have a very definite strike and dip, and 

 are transverse to the summit of the ridges, and they occur along 

 faults. There is not apparent the same amount of replacement 

 of the wall rock or corrosion of the included breccia as in the 

 case of the Ludwig and Douglas mines. Of these eastern ledges 

 the Blue Jay has been most prospected. The mineralization in 

 this case is confined to a belt about two hundred feet wide along 

 a fault. The ore, which at the surface is cuprite, occurs in cracks 



