STRUCTURE OF RUBY HILL. 29 



fissure, containing- decomposed rhyolite, is encountered. On the west side 

 of the fissure, which pitches easterly, interstratified limestone and shale 

 are found, the strata of limestone becoming less numerous as the quartzite 

 is approached. These beds continue for a distance of 134 feet and to within 

 10 feet of the quartzite, this interval being occupied by crushed Prospect 

 Mountain limestone. 



The main fissure in the jackson. — The fissure containing rhyolite is also found in 

 the Jackson tunnel. In proceeding downward it is next to be found on the 

 third level of the Jackson mine, though it may possibly make its appear- 

 ance in some of the abandoned workings which are now inaccessible. It 

 crosses the new Jackson shaft somewhere above the third level and con- 

 tinues with its usual dip and strike down to the fourth and fifth. It appears 

 at numerous points on all these levels and is invariably filled with rhyolite, 

 which is more or less decomposed. It is 150 feet from the quartzite on the 

 third level in the cross-cut to the old Jackson shaft, is about 15 feet from it 

 on the fourth, and comes in contact with it somewhere between the fourth 

 and fifth. It is 60 feet west of the shale on the third, and lies on the foot- 

 wall side of it on the fourth, in the before-mentioned cross-cut. 



The main fissure in the phanix. — In the Phcenix the main fissure, still filled with 

 rhyolite, is first noticed on the fourth level and continues with its accus- 

 tomed pitch and strike down to the deepest workings on the seventh level. 

 It is over 200 feet removed from the quartzite on the fourth, but comes in 

 contact with it about 40 feet below the fifth near the Jackson line. On the 

 sixth level, farther to the northwest, it is but a few feet from the quartzite 

 at the end of the cross-cut from the main incline. It may be as well to 

 state here that the depth at which the main fissure comes in contact with 

 the quartzite increases as the fissure is followed westward. Three hundred 

 feet farther to the northwest, on this same level, it is 50 feet southwest of a 

 body of shale, probably the same which is encountered in the Jackson. 

 On the seventh level it is almost everywhere in contact with the quartzite, 

 and is also in all likelihood in close proximity to the shale. 



Main fissure in the k. k. — The fissure is first encountered in the K. K. mine on 

 the third level and dips at its usual angle down to the deepest workings on 

 the ninth level. On the third it lies over 250 feet northeast of the quartz- 



