72 SILVER-LEAD DEPOSITS OF EUREKA, NEVADA. 



the relation that they bear to the secondary or contact fissure between 

 quartzite and limestone indicate that that fissure has often served as an ore 

 channel. This is more apparent as the ore is followed downward to the level 

 at which it takes up the whole of the space between the quartzite and the 

 main northeast fissure. (See cross-cut to Locan shaft, Plate VIII.) It has 

 been mentioned that most of the ore bodies in the Eureka lay along the 

 quartzite and limestone contact; but there has been one notable exception, 

 namely, the seventh and eighth level ore body. This, with its ramifica- 

 tions, reached to the northeast clay in places and extended from a short 

 distance below the fifth down to nearly the ninth level. It was the largest 

 single mass of ore ever found on the hill, and from it were extracted over 

 two million dollars. There have been several large bodies of ore near the 

 quartzite in the K. K. mine, but, with the exception of a mass near the sur- 

 face in the Jackson ground, the ore bodies in the portion of the mineral 

 zones lying southeast of the Eureka have not been very large. 



Northwest of the "compromise line" the ore has been found on the 

 quartzite in only one place, viz., above the fourth level of the Richmond 

 mine near that line. A reference to the various horizontal sections (Plates 

 XIII. and XIV.) will also show that the mineral zone or the wedge of lime- 

 stone between the two fissures is small in this part of the hill. The surface ore 

 bodies at the Champion, Buckeye, and Richmond claims of the Eureka and 

 Richmond companies were of very considerable extent, but at the present 

 time it is difficult to say how much ore was extracted from them, as the 

 workings have caved in many places and are inaccessible. In fact, exact 

 data in regard to the quantity of ore extracted from any of the ore bodies, 

 except those of the Richmond, are wanting; but as they are not necessary 

 to a geological discussion of the Ruby Hill deposits, they can be dispensed 

 with. 



Occurrences of the ore bodies in Prospect Mountain. There is Vdy little difference ill 



the manner of occurrence of ore bodies in Prospect Mountain and Ruby 

 Hill. On the mountain there are no workings in the neighborhood of the 

 quartzite, and thus far the metalliferous zones have been separated by belts 

 of undisturbed limestone and shale. The size of the ore bodies in the 



