458 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



ing drift between Vulture No. 1 and Vulture No. 2 is mainly in very much 

 decomposed Gray Porphyry, distinguishable by its mottled appearance and 

 occasional large crj^stals of feldspar. White Porphyry separates this from 

 the ore body of Vulture No. 2, and the contact between the two porphyries, 

 which dips to the eastward, is slightly iron stained. The ore body of Vult- 

 ure No. 2 evidently represents a small portion of the Blue Limestone, split 

 off from the main body by the lower White Porphyry and by this intrusive 

 sheet of Gray Porphyry, which is assumed to be the same found in New 

 Discovery No. 5, which, extending across Little Stray Horse gulch, connects 

 with the lower body on Carbonate Hill. The drift, in a southwesterly direc- 

 tion, from Vulture No. 1 to Colorado Chief No. 2, also crosses this body of 

 Gray Porphyry. Midway between the two shafts the top of the drift cuts 

 a body of fine conglomerate, resting immediately upon the porphyry and 

 apparently belonging to the Lake bed formation. Li the southeast corner 

 of this drift a winze has been sunk to a depth of 86 feet, jjassing through 

 the Gra}^ Porphyry sheet into an underlying iron body, from which ore 

 assaying 72 ounces to the ton was taken. The winze was abandoned on 

 account of the difficulty of handling water; but its exjjloration proved suffi- 

 ciently that the Gray Porphyry is a sheet dipping northeastward with the 

 formation and that a second iron body occurs below it. A large outcrop 

 of Blue Limestone, partially replaced on its upper surface and represented 

 on the map in the Kit Carson, Fairview, Pandora, Colorado Chief, and 

 New Discovery claims, belongs to this lower body, which is separated from 

 the main upper ore body by the cross-cutting White and Gray Porphyries. 

 The outlines given on the map are determined mainly by data derived from 

 the dumps of a few abandoned shafts, and therefore are probably not abso- 

 lutely correct. Its widest part is in the line of Section F, between Colo- 

 rado Chief No. 1 and Pandora No. 3 shafts, the latter finding some vein 

 material at its base. 



The portions of the mine thus far described, and which are shown in 

 the southern and western ends of Sections L, F, and B, respectively, were 

 opened in the earl)* days of ore development in the district, when it was 

 supposed that the ore bodies would probably be found to take a downward 

 direction towards the unknown sources below, from which they are gener- 



