442 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



sents a sketch of the north wall of the incHiie, near its head, in which, 

 however, the transition between unreplaced limestone and vein material is 

 less gradual than it is in nature. Above the contact in this mine, between 

 vein material and White Porphyry, is a varying thickness of white quartz- 

 ite, scarcely to be distinguished from porphyry. This is assumed to be a 

 portion of Weber Shales left above the Blue Limestone, as is so frequently 

 the case on Carbonate and Iron Hills. South of the Forsaken shaft the ore 

 body, which is a layer of sand carbonate at the contact, extends apparently 

 into the ground of the lower Evening Star, though these workings were 

 not accessible during time of examination. West of the south shaft of the 

 Forsaken, drifts run up along a barren contact into tlie Wash, which deepens 

 rapidly along the lower end line of the Evening Star claim. 



From the Forsaken incline south toward the Waterloo line, the forma- 

 tion rises apparently, though the connecting drift, which has a southeast 

 course, descends near this line on a steepening dip eastward. From this 

 drift, between the boundary line and the Main (or lower) shaft of the Water- 

 loo, an incline follows for a short distance a rich body of sand ore at an 

 angle of 25° to the east. At the head of this incline, directly over the ore, 

 is a thin sheet of White Porphyry, which is overlaid by Gray Porphyry. 

 This Gray Porphyry body dips steeply north and east and comes in actual 

 contact with the ore at the end of the incline. It is also cut in the bottom 

 of the Main shaft, where it is underlaid by vein material carrying a little 

 galena. This shaft is said to have passed through vein material and then 

 limestone before reaching the porphyry. South of the shaft a drift intended 

 to connect with the New Waterloo shaft is in limestone, which has an appar- 

 ent dip north. From the observations above noted, it would seem that the 

 Gray Porphyry is here cutting across the limestone up into the White Por- 

 phyry in a southwesterly direction, as it is in a westerly direction on the 

 line of Section B. Also that a slight anticlinal ridge runs along the Water- 

 loo-Forsaken line, from which, howevei', the Wliite Porphvrv lias not been 

 entirely eroded off, as it has on the line of Section B. This structure may 

 be seen graphically by supposing Section B to represent a noi'th-and-south 

 section across the Waterloo-Forsaken ore body on a line just west of the 

 New Waterloo shaft. There would be the same bowl shaped svncline, 



