224 GEOLOGI AND MINING INDUSTRY OF LEADVILLE. 



mation obtained from which is sufficiently indicated on the map and 

 sections. The Gray Porphyry sheet under the Pyritiferous also thins out 

 to the eastward and cannot be traced beyond the Colorado Prince fault. 



Colorado Prince fault. The movement of displacement of the Colorado 

 Prince fault is an upthrow to the southwest, which is about two hundred 

 feet in the middle and reaches a maximum at its junction with the Ball 

 Mountain fault and a minimum at that with the Weston fault. By this 

 movement the southern portion of the South Evans anticline has been cut 

 off and leaves, along the cliff at whose foot the fault runs, a succession of 

 beds dipping generally to the southward; to the faulting and consequent 

 exposure of the edges of these beds the steepness of the cliff is doubtless due. 



The White Porphyry sheet immediately over the Blue Limestone is 

 here very thin and in places entirely wanting. The Chemung tunnel <it 

 the western edge of this area, near the Weston fault, runs in a southeast 

 direction on the contact between the Gray and White Porphyries, and, 

 cutting across the latter, passes into the Blue Limestone. The Highland 

 Chief and adjoining shafts, a little east, of this, pass through the Gray Por- 

 phyry directly into silicious vein material, which is the replacement here 

 of the Blue Limestone. North of this the Eliza No. 2 (K-3) strikes Blue 

 Limestone, the Little Alice (K-2) Parting Quartzite, and the Eliza No. 1 

 (G 58) White Porphyry after passing about twenty feet of Wash, the last 

 reaching White Limestone at a depth of 180 feet. (Shaft No. 2 (G-51) of the 

 Miner Boy finds a small body of black shales directly above the limestone, 

 between it and the overlying Gray Porphyry. The Uncle Sam shafts (F 32 

 and F-33), at the east end of Idaho park, find vein material between Gray 

 Porphyry and Blue Limestone. The Rattling Jack and Little Johnny, still 

 farther east, find a sheet of White Porphyry between the Gray Porphyry 

 and Blue Limestone, with vein material at its contact with the latter. The 

 body of White Porphyry cut in the Little Alice and Eliza No. 1 shafts is 

 evidently of limited extent, as it has not been seen in any other workings. 



The White Limestone and Lower Quartzite are cut by the various 

 shafts and tunnels of the Black Prince, Miner Boy, and Colorado Prince 

 claims, the tunnel of the last running south through a body of White 

 Porphyry between the granite and Lower Quartzite and in close proximity 



