30 SILVER-LEAD DEPOSITS OP EUREKA, NEVADA. 



ite, and on the sixth it comes in contact with it. In the southeastern part 

 of the K. K. ground the quartzite face follows the course of the fissure, but 

 as the Eureka line is approached the quartzite bends westward. In the 

 lower levels the quartzite and the fissure are together for nearly the whole 

 of their extent, and the limestone is shut out from between them. 



Main fissure in the Eureka. — In the Eureka mine the Ruby Hill fault can be 

 noticed near the surface in the Bell shaft tunnel. This tunnel has been 

 driven in a southwesterly direction from a point 300 feet distant from the 

 compromise line to connect with the Bell shaft, and cuts through the fissure 

 about 50 feet from the mouth. The fissure can also be found in the Utah 

 tunnel near by, and is encountered in one or two other places, but it is not 

 an easy matter to trace it on the surface, as the seam is small and usually 

 covered with debris. At the surface it is about 700 feet from the quartzite. 

 It is not again met with in the workings of the Eureka mine until it is encoun- 

 tered in several cross-cuts on the fifth level. Its dip and strike between 

 these levels seem to be normal and to conform with the dip and strike in all 

 other parts of the mine. It is first found in contact with the quartzite on the 

 twelfth level, 1,030 feet below the top of the Lawton shaft. Near the K. 

 K. line the junction takes place somewhat above the twelfth level. In the 

 cross-cut to the Locan shaft, 12 feet above the twelfth level, the fissure which 

 lies between quartzite and shale is very narrow, but contains a foot or so of 

 ore. As this level is followed toward the compromise line the quartzite bends 

 around towards the west, a block of limestone intervening between it and 

 the fissure. The fissure comes in contact with the shale nearly as high up 

 as the ninth level, but the developments made at this point are not sufficient 

 to determine at exactly what point the junction takes place. On the little 

 tenth (60 feet above the tenth), tenth, and eleventh levels the main fissure 

 lies under the foot- wall or southwestern side of the shale as the compromise 

 line is approached. At or near this line on all these levels the shale bends 

 to the northeast, but the fissure continues its usual course. Its character in 

 this region can be best observed on the tenth level of the Eureka and the 

 seventh of the Richmond two corresponding levels. While in contact with 

 the shale the usual clay filling of the fissure is much thicker and stained 



