SOUTHEEN SLOPE OF CAEBONATE HILL. 413 



White Limestone and is best exposed in the bed of California gulch. It 

 does not seem to extend far up on Carbonate Hill, as it was not struck in 

 the O'Donovan Rossa shaft. Parting Quartzite, which forms the up])er jiart 

 of the Silurian limestone, is here very coarse-grained. 



The evidence for 'determining the line of the Carbonate fault in this 

 region is not very plentiful. A shaft and drill-hole have been sunk on the 

 northern bank of California gulch, south of the Harrison smelter, to a depth 

 of 200 feet in "White Porphyry, and are thus evidently to the west of the 

 fault. The Blind Tom shaft, on the road south of the California tunnel, 

 which was sunk 130 feet in White Porphjuy, is also west of the fault; 

 while another shaft, 50 feet south of this, was sunk in Silurian limestone, and 

 is hence east of the fault. The California tunnel (T-48) has been run into 

 the hill about seven hundred feet in a direction E. 15'^ S., or magnetic east. 

 The first 585 feet it is in White Porphyry, from which it passes suddenly into 

 the Blue Limestone, across a clay selvage. This is supposed to be the line 

 of the Pender}' fault, although the average dip is only 30° to the westward, 

 and it might possibly be supposed to be a folding of the limestone down- 

 ward in that direction. Unfortunately, the bedding planes are not suffi- 

 cientl}' distinct at this point to determine the question of a westerly dip. 

 There seems to be little doubt, from the extensive slickenside surfaces, that, 

 even if there be a westerly dip, there has also been considerable faulting 

 movement. The tunnel runs for the rest of its extent in Blue Limestone, in 

 which, toward the end, the bedding becomes quite distinct and the dip 

 assumes the normal angle of 20° to the eastward. It is evident from its 

 lower position relatively to the outcrops of the Blue Limestone on the hill 

 above that this is a continuation to the south of the portion of that body in 

 the ^tna claim which is west of tlie Carbonate fault and between it and 

 the Pendery fault. The line of the Carbonate fault has therefore been 

 drawn on the map according to this indication. It was observed that the 

 timbers supporting the roof of the tunnel from its mouth to the limestone 

 (which, owing to tlie soft and yielding chai-acter of the porphyr}- through 

 which it runs, were placed exceptionally close together) had a slight and 

 uniform inclination of 5° from the perpendicular to the west. It is not to 

 be supposed that they were originally placed in this position, and the infer- 



