44 MINING INDUSTRY, 



of a black, drusy quartz part it on the west from another zone of six feet of 

 ore-bearing quartz; this is also broken into blocks of a foot or less in diameter. 

 Next is 18 inches of black quartz fragments, and rounded, water- worn pebbles; 

 then four feet of white, blocky quartz, separated on the west by a seam of 

 dark greenish-gray clay from what is known as the Hawk-eye horse — a mass 

 of white quartzose propylite extending down to an indefinite distance, with a 

 lateral thickness of at least 300 feet. In general, the section is, first, country- 

 rock and clay parting; then 81 feet of quartz, arranged in zones of different 

 quality; then the white quartz-propylite, succeeded on the west by indistinct 

 propylitic country-rock, into which the 420-foot level of the Belcher has run 

 over 500 feet, but 'developed nothing important. 



In the Crown Point Mine, next adjoining the Belcher on the north, is a 

 totally different structure: see section on Atlas-Plate 8. Here are two 

 distinct bodies. The west vein, as it is called, dips at about 48° to the west, 

 extending down to a vertical depth of 400 feet. Opposite the Crown Point 

 shaft, where it is cut successively by the 160, 230, 300, and 400-foot levels, it 

 is a mere seam at the surface, steadily increasing downward, and reaching a 

 breadth of 20 feet on the 160-foot level, and of 50 feet on the 400-foot level. 

 The quartz composing it is broken and blocky near the surface, and in depth 

 becomes more and more fractured and crushed to a sugary condition. It has 

 a prevailing red tint, from surface infiltrations. Both the selvages are sheets 

 of pure, homogeneous clay, without pebbles, from a foot to three feet in thick- 

 ness. On the 400-foot level this vein is cut off by a smooth wall of rock, 

 covered with a facing of clay, and lying nearly horizontally, but with a slight 

 inclination to the east. On the section through Crown Point and Yellow 

 Jacket shafts, of this Plate, this body and horizontal cut-off are shown. In the 

 west vein, ore began west of the Crown Point shaft, 75 feet below the surface, 

 and filled the whole vein down to the 400-foot level, with a longitudinal extent 

 of almost 500 feet, running through the Kentuck mine into the Yellow Jacket, 

 for a distance of 200 feet. Its cap-like figure is shown on Atlas-Plate 6, as 

 Crown Point west bonanza. At a distance of 100 feet to the east of the shaft, 

 see section on Atlas-Plate 8, stands a nearly vertical vein of quartz, which 

 at this point begins on the east wall, at a depth of 200 feet below the surface, 

 and widens downward, reaching a maximum of 125 feet on the 700-foot level. 



