364 GEOLOGY OF THE COMSTOCK LODE. 



General remarks, — Tlic opiuion lias becii expresscd (pa<^e 35 1 ) that the field of 

 electric excitation is confined to particular parts of the ore body. That this 

 should be the case is not surprising, as the conclusion has already been 

 reached that contact between different kinds of material is necessary for the 

 production of currents. In the connection made between chambers No. 14 

 and No. 15, as well as in the survey on the 400 and 500-foot levels, the ore 

 actually met with was principally lead carbonate, at times stained with sul- 

 phide and ferric oxide. Now, disregarding the sulphide, which is here very 

 unfavorably associated, more pronounced electrical properties can hardly be 

 ascribed to the remaining constituents of the deposit than to the surrounding 

 rock itself For, judging from physical properties, cerusite maybe regarded 

 as an insulator with as much right as calcite, earthy lead carbonate as lime- 

 stone. In fact, it seems to follow that the feeble, though none the less 

 positive, reaction observed on the 600-foot level is already partially obscured 

 when the line of points on the 500-foot level is reached, and would perhaps, 

 cost, par., be equally obscured on the 700-foot level. I am also inclined to 

 infer that the currents observed on the surface are not due, or, rather, not 

 immediately due, to the deeper ore bodies (Nos. 1 1, 12, 13, 14, 15, etc.), but 

 to the deposits, also of considerable size, occurring in what are known as 

 the Lizette Tunnel workings. The entrance to the latter is on a level with 

 the mouth of the shaft, and the ore masses are distributed in a vertical range 

 from Point I. to a level even above Point X. on the surface. These ore 

 bodies, throughout their extent, are comparatively near the line of holes 

 used in the surface survey. It is, moreover, quite probable that an inti- 

 mate connection exists between these and the large group of ore bodies 

 below. 



In consideration of the statements made in the foregoing paragraph, 

 and allowing as accurately as possible for discrepancies, the results thus fiir 

 reached may be regarded as agreeing well with the fundamental hypothesis. 



