FAULTS ON IROX HILL. 385 



huiuli-ed feet through White Porphyry, on the west side of the fault, into 

 Lower Quartzite on the east side; by two shafts on the Lingula claim; and 

 by numerous sliafts and winzes in the claims of the Iron mine, some of the 

 latter being sunk on the plane of the fault itself, and showing its average 

 dip to be 60"^ to 65° to the westward, or nearly at right angles to the dip 

 of the formation. 



As the Blue Limestone has not yet been reached on the west side of the 

 fault in the region represented on this map, its movement of displacement, 

 or throw, cannot be accurately determined. Its maximum is probably not 

 far from one thousand feet, since the Cit) of Paris shaft, 1,200 feet north 

 of the line of the map, was sunk to a depth of 800 feet without reaching 

 the Blue Limestone. The dip of this bed carried back from the outcrop 

 oh Carbonate Hill, at the average angle, would reach at the line of the 

 fault a much greater depth, probably not less than fifteen hundred feet ; 

 but there are good grounds for assuming that this dip shallows, and that 

 the beds actually basin up, i. e., assume a westerly dip, before reaching 

 the line of the fault. The movement of this fault may here be parth' dis- 

 tributed among smaller parallel faults to the west, like the Carbonate fault, 

 in which case the contact immediately adjoining the main fault may be found 

 at a less depth than 1,000 feet. To the north, beyond the limits of this map, 

 as has already been s:en in the general description of the Leadville region, 

 the movement of the Iron fault graduall}- decreases and it apparently j^asses 

 into an anticlinal fold As regards the continuation of the fault south of 

 California gulch, however, no definite data have been obtained, since the 

 great accumulation of Wash and Lake beds there have been a barrier 

 to underground explorations. It has been assumed that it gradually 

 passes into a synclinal fold, as indicated on the majj of Leadville. The 

 movement of displacement south of California gulch is, however, distributed 

 among two faults, the Dome and the Emmet, with which the Iron fault is 

 connected by a cross-fault (the California fault), which follows approx- 

 imately the bed of California gulch. 



California fault. — The plane of this fault has not been actually cut, but its 

 existence is proved by the discrepancy of the beds on either side of the 



MON XII 25 



