ASPEN SPECIAL MAP. 67 
Since the dip of this fault is mainly toward the west, this movement 
is indicative of a reversed or thrust fault; and in a general way this seems 
to be its nature, although, as already stated, in the lower part of this fault, 
as exposed in mine workings, the downthrow on the east side is the 
direction of the dip, and so constitutes a normal fault. 
The Aspen fault is probably restricted in extent, both to the north 
and to the south. Its maximum development probably coincides with the 
maximum amount of folding in the Aspen Mountain syncline, and this 
maximum folding apparently occurs in the southern part of that portion 
of Aspen Mountain which is shown on the Aspen special map. This fault 
can not be traced any distance southward in the area of the Tourtelotte 
Park special map. In Section A of the Tourtelotte Park mining map 
(Atlas Sheet XXII) it is represented as being present, but with a very 
slight throw; and it seems quite certain that it does not exist far south 
of the plane of this section. On the northern end of Aspen Mountain 
there also appears to be a marked dimmution in the mtensity of the 
folding and in the amount of displacement by the Aspen fault. Section C 
of the Aspen Mountain map (Atlas Sheet X XVI) probably traverses the 
point near which this fault has its greatest development. In Sections A 
and B of the same map it is represented as bemg present but having much 
less importance. It probably dies out to the north under the Roaring Fork 
Valley, and is therefore more restricted than any of the other north-south 
faults which have been described, being present only on Aspen Mountain. 
In the process of mining large and valuable bodies of ore have been 
discovered along this fault, so that it belongs to the same general class as 
the faults which have already been mentioned, namely, the premineral faults. 
Bonnybel and Chloride faults—These faults are shown on the map as having 
only a limited extent. They are approximately parallel, having a general 
northwest trend and a southwest dip. They are well shown in the Bon- 
nybel and Durant mines, where their existence and the amount of disloca- 
tion have been well determined in the course of extensive lawsuits. - Like 
many other faults, these are not simple; but, strictly considered, the 
disturbance has consisted in the breaking up into thin slices of a wedge 
of rock, which has a northwest trend and a southwest dip. Within this 
wedge there are many faults parallel to its sides, all of which have some 
throw. For purposes of discussion, however, the displacement may be 
