64 GEOLOGY OF ASPEN MINING DISTRICT, COLORADO. 
Mountain has a northerly pitch, steeper than the slope of the mountain; so 
that successively higher and higher beds outcrop toward the north along 
each of these faulted blocks. The shifting in position of the upper contact 
of porphyry and shale is shown by the fact that the Great Western and 
New York tunnels run in porphyry on the west side of the fault, while on 
the east side there are only Weber shale and limestone developed by the 
explorations; and on the latter side the porphyry is found only near the 
top of the hill. 
The displacement of the Sarah Jane fault is chiefly a dewnthrow on 
the east side, never very great. In the northernmost of the 300-foot sec- 
tions on the Aspen Mountain map it is shown to be about 300 feet. (See- 
tion A, Atlas Sheet XXVI.) In Section B it is drawn as having about 
200 feet downthrow, and in Section C, which is the southernmost, about 
350 feet downthrow. ‘These measurements are, however, based on very 
few data, and ave, therefore, not necessarily accurate; doubtless the actual 
throw of the fault may be more uniform than has been represented. 
To the south the Sarah Jane runs into Tourtelotte Park, where there 
are many outcrops and mine workings which afford abundant opportunity 
to trace its course. ‘These explorations show that while the throw is always 
downward to the east, yet it continues to decrease slightly toward the south; 
so that in the middle of the area shown on the Tourtelotte Park special map 
it dies out and is not farther traceable. This fault has not been prospected 
to any extent on Aspen Mountain, but in Tourtelotte Park it shows evidence 
of belonging to the same general class as the Saddle Rock, Pride, and Cas- 
tle Creek faults, since it is mineralized to a greater or less extent along its 
whole course, and since there is no evidence of any great movement subse- 
quent to the ore deposition. 
Schiller fault—The Schiller fault may be traced on the surface, but is best 
shown underground, in the Durant, Schiller, and Aspen mines. This fault 
has a north-south trend and is nearly vertical. It belongs to the same 
general system as the faults which have already been described, but it has 
a greater difference of throw at different places than the others, as shown 
in sections taken at various points. In the southern part of the Durant 
mine, which is almost exactly below the southern edge of the district 
mapped, at the point where the outcrop of the Schiller fault passes mto 
the area of the Tourtelotte Park special map, the fault seems to have very 
