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MINING INDUSTET. 



valuable locations have been made. Among these the Virginia is the most 

 developed and productive. Its ores, however, are said to differ essentially 

 from those of the mines above named, the silver being combined more inti- 

 mately with metals of inferior value. 



Ebeehaedt. — The Eberhardt claim, which now includes the Keystone and 

 others that were originally made in the same vicinity, extends in an east and west 

 direction across the south slope of Treasure Hill, some 700 feet below the peak. 

 The total length of the claim, acquired by location and by purchase, covers 

 1,800 feet. It is described as a " ledge," or true fissure vein, and held under 

 laws which apply to that form of deposits ; but whether it is such, or what its 

 true relations are to a fissure vein, is a matter concerning which intelligent men 

 hold conflicting opinions. It may not be a fissure vein, in the generally 

 accepted sense in which that term is used, although it possesses some analo- 

 gous features that are more notable in this than in many of the other produc- 

 tive deposits of the district. It is situated in the line of a fissure or fault 

 that has broken and displaced the limestone strata, which here compose the 

 country-rock. The direction of this break is east and west, traversing the 

 south end of the hill. The line of fracture is perfectly well marked, showing, 

 as far as exposed by the Eberhardt workings, along the surface or in depth, 

 an east and west course and a dip to the south of about 85°. This is regarded 

 as the north wall of the Eberhardt ledge. It has been traced along the sur- 

 face for a distance of several hundred feet; a shaft has been sunk upon it 192 

 feet, and at the depth of 85 feet a drift has been run 240 feet, in all of which 

 work the plane of fracture is shown to be regular and well defined. 



South of this "wall," 184 feet distant, when measured on the surface at 

 the Eberhardt deposit, is a similar line of fracture, though less well defined, 

 having about the same course, and dipping to the north at an angle between 

 85° and 90°. This is regarded as the south wall. Included between them 

 is the Eberhardt deposit, which, when visited by the writer in September, 

 1869, appeared to extend across the "fissure" from side to side, and longitu- 

 dinally, between 100 and 200 feet. The depth from which ore was being, or 

 had been, extracted, in considerable quantities, did not exceed 50 feet. The 

 material composing the deposit consists chiefly of brecciated or shattered 

 limestone, the small fragments of which are held together by quartz and crys- 



