THE COMSTOCK LODE. 81 



In general the ore within the limits of bonanzas is pretty uniformly dis- 

 seminated through the quartz. It is only rarely that large, solid accumulations 

 occur. The silver minerals ordinarily lie in masses about the size of a hen's 

 egg. In the central portions of bonanzas there is usually a somewhat denser 

 arrangement of ore; and, in their relations to the bonanza systems, the 

 northern halves of the two groups are the richer, and the charging is more 

 and more dense toward the surface. It is evident, from the manner in which 

 the ore itself is broken and dislocated, that the dynamical action which pow- 

 dered the quartz occurred after it was charged with ore. 



There is every reason to suppose, from the manner in which the ore 

 minerals intersect the quartz, that they were deposited while the latter was 

 still plastic. Since the period of crushing, additional charges of quartz and 

 ore have been introduced into the fissure to a small extent. In a few cases, 

 as in the 800-foot level of the Yellow Jacket mine, broken fragments of 

 quartz, themselves containing ore, have been re-cemented by sheets of steph- 

 anite which have penetrated the cracks, and over the stephanite a secondary 

 growth of quartz crystals has taken place, and these quartz crystals themselves 

 are again coated with a fine varnish of silica. The carbonate of lime which 

 is found in the lower works of Grold Hill and Hale and Norcross, but more 

 especially in the former, has crystallized in the cavities of the quartz, and in 

 some instances has been subsequently coated with a film of quartz and then 

 dissolved out, leaving skeleton crystals built up of thin films of silica. In the 

 Middle Savage mine, in the region of the second station, for a considerable 

 time quartz and ore alternated in deposition. There is a limited region where 

 the ore and quartz form alternate concentric layers. Outside of the most 

 recent layer of ore, in rare instances, has been formed a plating, about half an 

 inch thick, of carbonate of manganese, which in its turn was again covered 

 with a thin layer of silica. 



The ores of Gold Hill and Virginia are very similar in their mode of 

 arrangement and general mineralogical composition. Stephanite occurs much 

 more sparingly in the Virginia mines than in Gold Hill. In all the ore 

 that has been worked the average proportion of gold remains very nearly the 

 same. In the uppermost works of the Belcher, in the upper levels of the 

 Gold Hill group, and in the very highest portions of the Gould and Curry 

 11 



W' 



i/ 



