386 GEOLOGY a:ND I\lIjSri^^G IIN'DUSTRY OF LEADVILLE. 



gulch, the Blue Limestone outcropping near the Robert Emmet tunnel and 

 opposite the Globe shaft, in which the Lower Quartzite is cut.' 



Dome fault. — The Domo fault is in one sense the proper continua1i"on of 

 *'lje L-on fault, since it forms the great break on Dome Hill, as Iron fault 

 does on L-on Hill, and, like the latter, passes at its extremity into an anti 

 clinal fold. Considered in this way, the L'on, California, and Dome faults 

 would form a single fracture, somewhat irregular in direction, but having a 

 general north-and-south trend, while the southern continuation of the L-on 

 fault, as at present indicated, and the P2mmet fixult, would be simply 

 branches, relieving the strain at the sudden bend of the fault in California 

 gulch. To the east of this line of fracture are the principal outcrops of Blue 

 Limestone and the main ore developments in this region, while to the west 

 this horizon is more or less deeply buried beneath a covering of porphyry. 

 The Dome fault proper has a general north-aii^l-south direction. Ls plane 

 has been proved b"S" underground workings only in the Vining tunnel, but 

 the line as given on the map Is tolerably closely determined by the develop- 

 ments of adjoining shafts and Inclines, those on the west finding White 

 Porpliyr}', underlaid b}' Gray Porphyry, on a level with Blue Limestone on 

 the east, in the Rock and Dome workings. 



Emmet fault. — Tills Small fault, running In a southwest direction from 

 the California fault, has a movement of displacement the reverse of the 

 majorlt}' of the faults in this region — that Is, the upthrow Is to the west in- 

 steadof tothe east. Ls plane has actually been proved byadrift runnlngwest- 

 ward from a winze sunk In the Robert Emmet tunnel. L is further proved 

 by the discrepancy in the position of the Blue Limestone and the overlying 

 porphyries on either side of it, as shown In Section G, Atlas Sheet XXV. 

 That it actuall}' continues to its junction with the L-on fault to the south, 

 as indicated on the Leadville map, is merely a matter of conjecture. 



Dome Hill. — By reference to Atlas Slieet XXV, Sections E and F, It will 

 be seen that the northern portion of the ridge of Dome Hill, adjoining Cal- 



' Since tlie close of field- work, developments iu the Giirden City mine have definitely located the posi- 

 tion of the we.steni end of thi.s fanlt. The lower shaft on (his claim was snuk perpendicularly UHl feet 

 throuKh limestone and vein material, aud Ihen passe<l into the Lower Quartzite, crossing the fault 

 diagonally. At 120 feet a drift to the southwest cut the fault at !i feet from the shaft, shov.-ing that 

 its rlip is to the south. At 75 feet from the^haf^ the sante drift cut the plane of the Iron fanlt and pa>-.e'd 

 into 111!' Wliite Porjdiyry on the west side of this fanlt. 



