HENRIETT AND WATERLOO MINES. 441 



S 



has been entirely replaced and structure lines are obliterated. In the lower 

 workings of the Henriett mine, moreover, near the prolongation of the fault 

 line, Parting Quartzite was found in the floor of a drift, which proves that 

 at this point the ore body is near the base, whereas in the shafts it was 

 near the top, of the Blue Limestone. The line of Section B is apparently 

 the line of greatest depression of the Gray Porphyry sheet, since to the 

 north what is apparently a slight fault brings the limestone up, cutting off 

 the ore body, and on the south, towai-ds the New Waterloo shaft, the con- 

 tact rises. This shaft was sunk entirely through vein material and Gray 

 Porphyry, and apparently found no White Porphyry. The faulting move- 

 ment has here become a slight down-throw to the east, comparable in di- 

 rection and amount to the Morning Star fault, and which might readily be 

 mistaken for a simple monoclinal fold. It is assumed to be the continuation 

 of the Carbonate fault, though there is no direct proof, nor could a con- 

 nection actually be traced, since the throw of the latter would become nil 

 between here and where it is actually demonstrable. On the same line to 

 the north, in Little Stray Horse Ridge, there is a displacement, which passes 

 into an anticline on Fryer Hill, in the Dunkin ground. 



West of the Halfway House shaft the contact between limestone and 

 White Porphyry has been explored for ore, and is found to be cut off by a 

 sudden deepening of the Wash, which evidently represents the shore-line 

 of Lake Arkansas mentioned above. In the Jolly shaft the Wash is 140 feet 

 deep and an east drift from it finds vein material and limestone. 



The map shows an eroded anticline west of the Jolly shaft, which is 

 the southern continuation of the quaquaversal, shown on the Leadville 

 map, between the west ends of Fryer and Carbonate Hills. 



Morning star and Forsaken. On the line of Section C the underground data 

 are less complete, and the structure, which is even more complicated, is 

 consequently determined with less certainty. The rocks passed through 

 by the Waterloo Lower, Forsaken, and Portland shafts could not be deter- 

 mined by actual observation, and the information obtained may not be in 

 every case geologically accurate. In the Forsaken incline the limestone 

 dips regularly eastward, and the action of replacement, acting from the sur- 

 face downwards, is very clearly shown. Figure 4, Plate XXII, repre- 



