38 SILVER-LEAD DEPOSITS OF EUREKA, NEVADA. 



with those two belts and also that it is accompanied by a fissure on its 

 hanging-wall side similar to the one which occurs in a similar position with 

 it in the Jackson mine, would tend to prove that these three bodies of shale 

 were parts of a continuous belt. They are moreover identical in their 

 physical character. 



connection of the two belts of shaie. — If the shale is traced from the point where 

 it is found over the main incline on the tenth level of the Eureka past ihe 

 compromise line into the Richmond seventh, and from the seventh up to 

 the sixth, and so on up to the fourth, and thence through the shaft to the 

 surface, the continuity of shale from the lowest workings of the Eureka up 

 to the spot where it comes to the surface back of the Richmond hoisting 

 works is established. But, on the other hand, if it is followed upward from 

 the place where it is exposed in the cross-cut to the Locan shaft on the 

 twelfth level of the Eureka along the line of its contact with the main fis- 

 sure, it is lost sight of above the little tenth level of that mine. If it fol- 

 lowed the fissure, it would be found on the surface about 800 feet south- 

 west of the Locan shaft, and in the Bell shaft tunnel. But the shale on the 

 surface lies over 300 feet northeast of that shaft. There is no other shale 

 on the surface between the Locan and Lawton shafts, and none is found in 

 the former shaft until a depth of 1,020 feet is attained. The shale on the 

 surface, however, northeast of this shaft can be followed around to the 

 southwest of the Richmond hoisting works, so that the two masses of shale, 

 the upper and lower, must be connected somewhere below, the Locan shaft 

 being sunk in the limestone between them. (See Plate I.). 



Causes which produced the junction of the two shale belts. TlirOUgll the faulting incident 



to the upheaval the lower belt of shale has been brought into contact with 

 the upper or surface shale somewhere near the compromise line. At exactly 

 what point this junction takes place, it is a difficult matter to determine, 

 except on the tenth level of the Eureka and the seventh and eighth of the 

 Richmond, owing to the insufficiency of the explorations and the broken 

 character of the ground; but it is evident that there is a junction as will be 

 seen if the surface map is compared with the underground sections. 



There is a sharp bend in the shale contact on the surface along the 

 compromise line. From observations made below on the sixth, seventh, 



