128 GEOLOGY OF ASPEN MINING DISTRICT, COLORADO. 
FAULTING. 
Silver fault—The Silver fault is traceable across the district, either by 
outcrops or, more accurately, by underground exploration. It has always 
been well recognized that this plane is one of the most favorable localities 
for prospecting, and so there is a continuous series of shafts or other work- 
ings set at a short distance from one another along the whole line of the 
fault. These workings always reveal at this plane the broken and shattered 
zone, which shows this to be a true fault contact. The outcrop of this 
fault, as shown on the map, is not strictly parallel to the formation lines, 
although in a general way it is so, and the deviation from parallelism illus- 
trates its fault character. In the northern part of the district the fault lies 
between the Weber shales and the Leadville dolomite, and there is lacking 
only the Leadville blue limestone to make up the entire section. In the 
central part, however, the Silver fault tends to approach the underlying 
strata toward the south, so that it cuts across the Leadville dolomite into the 
Parting Quartzite, and at a point near the top of the isolated hill seen in 
the accompanying plate it cuts across the Parting Quartzite into the Silurian 
dolomite. These ditferent formations come successively to rest against the 
shale, which persists on the northwest side of the fault. It is probable that 
the occurrence of Weber shale resting upon Silurian dolomite, as found in 
the vicinity of the Badger mine, is continuous across the creek under the 
drift covering, for in the workings on the southern edge of this drift we 
find the same conditions. At a point near the southern termination of the 
outcrop of the Silver fault this fault cuts upward again across the strata, 
revealing the whole of the Silurian dolomite, then the Parting Quartzite, 
and finally cutting up into the Leadville dolomite. It does not, however, 
get to the top of this last formation, and in the whole Hunter Park district 
there was found no trace of the Leadville blue limestone. 
Lenado fautt— The Lenado fault is shown on the northern part of the 
map, but it is not actually traced across this district. From the trend of 
the fault when last identified it must cut the Hunter Park area in about the 
line indicated, and from its great throw at Lenado it must persist for a 
long distance. In the thick red sandstones, however, which present no 
well-marked difference from top to bottom, it is impossible to follow any 
fault, and an additional difficulty is introduced by the drift covermg. The 
probable effect of the fault is to bring the Triassic beds on the north 
