m 



GEOLOGY AND TOPOGRAPHY OF THE LEAD REGION. 



Fig. 17. 



Vein-Stohb Breccia, Stopiinb Diggings. 



The breccia consists of small, 

 an^lar pieces of Galena lime- 

 stone, similar to the acljaccnfc 

 rock of the formation. It ap- 

 pears to have been caused by 

 the undermining and falling in 

 of a portion of the formation, 

 by a previous subterranean 

 drainage. The rubbing and 

 grinding of the sides of the fis- 

 sure against each other in the 

 course of the movement broke 

 off pieces of various sizes, and 

 the interstices and cavities were subsequently filled with pyrites. 



McNulty Mine. In June, 1873, work was recommenced on these old ranges, and 

 considerable capital expended in erecting new machinery and buildings, the old ones 

 having been previously burned. It is now owned and operated by Messrs. J. M. Ryan, 

 of Galena, and M. A. Fox, of Shullsburg. 



The mine is situated on the N. E. qr. of the N. E. qr. of Sec. 15, T. 1, R. 2 E., a 

 short distance south of the village of Shullsburg. There is here a thickness of about 200 

 feet of Galena hmestone, or four-fifths of the entire formation. The ore is obtained in 

 the usual opening common to all the mines of the Shullsburg district, between what.aro 

 known as the green and clay beds, of which the green bed is regarded as the top and 

 the clay bed as the bottom of the opening. In this mine the following stratigraphical 

 information was obtained: Five feet below the clay bed, ajid l-aO feet below the sur- 

 face is an opening, and a bed of white rock two feet thick, then a layer of hard gray 

 rock three feet. Below this was found a flat sheet of galenite, mixed with pyrites, and 

 indications of an opening below. It is a peculiarity of the mining ground on this ridge, 

 that all crevices south of the Shullsburg branch pitch or dip to the south, about six 

 inches in ten feet, until the summit of the ridge is reached. Here, as in the south shaft 

 of the McXulty, the crevices are vertical. In this shaft the crevice penetrates through 

 the clay floor, and continues on going down, being the only crevice which has done so. 

 Proceeding further south, over the crest of the ridge, the crevices all dip or pitch to the 

 north. Taken together, tliis system of crevices seems to present a fan-like shape, ap- 

 proaching one another as they descend. In the spring of 1876, a new east and west 

 range was discovered in this mine, south of and parallel to the one already worked. 

 It promises to be veiy productive of lead ore. The production of this imne from June 

 1, 1873, to :\Iarch 1, 1876, is as foUows: 1873, 200,000 pounds; 1874, 1-50,000 pounds; 

 187.J, 75,000 pounds; 1876, 210,000 pounds. 



Rickert, Stevens & Co. These diggings are situated on the N. W. qr. of the N. W. 

 qr. of Sec. 14, about 500 feet east of the McNulty mine, and connected with it. Theu: 

 geological position in respect to strata and openings are almost the same. The ore is 

 found in the usual Shullsburg opening, but in a few instances it rans above it for a short 

 distance, and then drops down again, presenting a sadcUe-shaped appearance. At the 

 south shaft the rock is very much disturbed and broken, apparently in an area of about 

 200 feet in diameter. It is in loose masses of all sizes and shapes, containing more or 

 less ore scattered through it, and the fine earthy material known among the miners as 

 sand. The strata pitch in every conceivable direction and degree, from horizontal to 

 vertical, crevices and veins cannot be followed through it with any degree of certainty; 

 but at the borders of this disturbed area, as well as above and below it, the strata, ha\-c 

 then- normal position, winch is nearly horizontal. This is merely a local disturbance, 

 and is probably due to the unequal hardness and solubility of the formation. Consider- 



