46 MINDsG mDUSTEY. 



360-foot level was driven due v^^est through this vein, and 120 feet west into 

 the country-rock, which proved to be a metamorphic schist. The workable 

 ore rises about 50 feet above the 190-foot level, and ends in the quartz like a 

 wedge. 



The whole east vein in this section has a greater inclination to the 

 east than in the Crown Point : from the 200-foot level it pitches to the east at 

 an angle of 50° with the horizontal. No ore was inclosed in it until 550 feet 

 below the mouth of the shaft, where the silver deposit began on the east clay 

 and widened downward, until at the 730-foot level it was 20 feet wide. On 

 the 840-foot level, a little south of this section, the drift developed ore all the 

 way through the Kentuck and the Crown Point; 600 feet north of the shaft, 

 on this level, ore also occurs directly under the old north workings of the west 

 vein. At the present deepest level the ore reaches from the Crown Point 

 north line to the Yellow Jacket shaft, and, after a barren interval of 200 feet, 

 continues 190 feet further north, with the breast still in ore. This is well 

 shown on Atlas-Plate 6. 



Passing now to the section through the Yellow Jacket north shaft, it will 

 be seen that the west vein has almost disappeared and is only represented by 

 a thin seam of quartz, eight feet thick, faced with thin layers of clay. The east 

 vein, on the contrary, has increased extraordinarily. Its surface width is 200 

 feet, thinning down with irregularly curving walls to the greatest contraction 

 on the 525-foot level, where it is only 45 feet wide, but rapidly makes in depth 

 to the 700-foot level. Here it is singularly broken oif by a- dike of quartzose 

 propylite. A clay-vein parts the dike from the quartz. When the working 

 connections shall have been made between this point and the lowest level from 

 the south shaft, the nature and extent of this intrusive porphyry will be under- 

 stood; but at present little can be said of it. An air connection has been 

 lately made between these points, developing, as was expected, the imperfect 

 continuity of the quartz. Silver ore is confined to the zone from 30 feet above 

 the Union Tunnel to 40 feet below the 530-foot level in the old works. It is 

 hoped and believed that the most northern ore in the 940-foot level will rise 

 nearly to the bottom of the north mine-works. There are two bonanzas lying 

 in the same quartz-mass, separated by an interval of barren rock. They are, 

 in fact, the southern ends of the Gold Hill bonanzas. Their upper outlines 



