426 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



with a small proportion of unaltered galena. The ore sheet which extends 

 from the Carbonate into this ground seems to be growing narrower and less 

 continuous and may disappear entirely to the northeast. It is as yet, how- 

 ever, not safe to assume this as a fact, for the ground in the Yankee Doodle 

 claim has not yet been thoroughly and systematically prospected ; more- 

 over, the shaft sunk on the Excelsior claim, which is nearly in the line of 

 the probable continuation of this ore body, is said to have cut a large body 

 of vein material, which, though not rich, is an evidence of mineralizing 

 action. 



From the middle shaft of the Yankee Doodle, which is about one 

 hundred feet in depth, considerable ground has been explored by an incline, 

 from which two sets of levels have been run oflP Both incline and levels 

 are very irregular, following the var3'ing inclination of the contact between 

 limestone and porphyry. 



From the end of the first level north a winze was sunk, apparently in 

 a considerable body of vein material, in a sudden steepening of the lime- 

 stone. As it will be seen by reference to the map and sections that this 

 point is on a line with a similar sharp bend in the limestone, at the southern 

 extremity of the drift on the sixth level of the Crescent mine, where indica- 

 tions of a body of rich ore are found, it would seem advisable to have 

 pushed explorations farther at this point, with the prospect of developing 

 one of the smaller bodies of ore, such as are found to the west of the main 

 Carbonate body, between it and the ^tna line. The south drift on this 

 level follows a barren contact of the usual character, viz, showing black- 

 ened decomjDOsed limestone, with the usual parting of Chinese talc sep- 

 arating it from the iron-stained porphyry above, which contains fragments 

 of black chert and quartzite. 



On the second level some thin seams of sand carbonate are found to 

 the north of the incline, and at the southern extremity a considerable Ijody 

 of this ore has been stoped out. This also is evidently worthy of further 

 exploration. It thus appears that the apparently barren zone between the 

 two rich ore bodies or bonanzas of Carbonate Hill is only a region wheie 

 the ore is less continuous than in the bonanzas themselves, and that several 

 small ore bodies have been found there, and probably by a systematic 



