332 GEOLOGY OF TEE COMSTOOK LODE. 



No. 12 is a continuation of No. 11, beginning on the 500-foot level 

 and ending 70 feet below this level. 



No. 16 commences 50 feet above and runs 70 feet below the 200-foot 

 level; the bottom of the present workings. 



No. 15 commences on the 300-foot level and continues to the 500-foot 

 level. 



No. 14 begins 50 feet above the 400-foot level and continues to within 

 50 feet of the 600-foot level. 



No. 13 begins at the 500-foot level and continues 50 feet below the 

 600-foot level. 



Chambers Nos 13, 14, and 15 are all connected and form one ore 

 body. No. 16 will undoubtedly connect also with these three, so that in 

 fact Nos. 13, 14, '5, and 16 are but lobes of one and the same huge deposit. 



The greatest horizontal extent of these bodies is between the 4()0 and 

 500-foot levels, the plan showing the following dimensions: 



N.toS. 520 feet. 



i:.to W. 600 feet. 



No. 7 extends from the 400-foot level to 50 feet below this level. 



No. 10 begins 20 feet above and ends 50 feet below the 400-foot level, 

 and is exhausted. No. 13 also is partially exhausted. 



East of the group of ore bodies of the Richmond Company are those 

 of the Eureka Consolidated Company, which are also of unusually large 

 dimensions, the ore being the same in every respect. 



Experiments on the 500 and 4oo.foot levels. — Thcsc scrics of mcasuremeuts Were made 

 with the intention of observing the variation of potential met with in pass- 

 ing through the ore body, the line of electric survey beginning and termi- 

 nating in points as far distant from it as was practicable. 



The plan of the position of the drifts on the 500 and 400-foot levels 

 relatively to the ore chambers, so far as is necessary for the present purposes, 

 is given in Fig. 27, on a scale of ~^. Starting with the shaft at m, the drifts 

 are represented by broad black lines. The main drift on the 400-foot level, 

 passing from a point between VIII. and IX. on that level in an approxi- 

 m;itely semicircular path toward the shaft, has, as well as other workings. 



