230 GEOLOGY OF ASPEN MINING DISTRICT, COLORADO. 
Mountain the ore occurs along the Contact, Aspen, Chloride, Bonnybel, 
Schiller, Pride, Mary B., and other faults. In Tourtelotte Park the chief 
mineralization has taken place along the Contact and Silver faults, but the 
ore shoots follow east-west and north-south fractures which cut these flat 
faults. On Smugeler Mountain ore is found along the Silver fault, but 
chiefly at its intersection with other faults and fractures which belong for 
the most part to the Della system; and in Queens Gulch and southward to 
the Little Annie mine, ore is found on the Castle Creek and its dependent 
faults. In all these cases the ore has evidently formed in place and has 
been deposited since the fault movement, for the breccia which was formed 
by this movement has been replaced and cemented by metallic minerals 
and by gangues, so that it very often forms the chief ore. In other faults 
ore is found broken by the movement along the fault in which it occurs, 
showing that the displacement took place, partly at least, subsequent to 
the ore deposition. Often, again, ore bodies which have formed in place 
along a fault have been disturbed by some subsequent movement, whose 
plane intersected the plane of the first. 
The Silver and Contact faults, which lie close to the bedding, have 
been most important in determining the deposition of ore. These have 
been followed throughout the district as the most likely localities for 
discovering ore bodies, and thus the most productive zones run very close 
to them. It is not everywhere, however, that they are sufficiently mineral- 
ized to form ore. Indeed, this is not generally the case. The actual ore 
bodies are usually found at the intersection of these faults with some fault 
belonging to a different system. Along such a line of intersection the 
mineralization has taken place in continuous and definite shoots. The case 
of Smugeler Mountain may be cited, where nearly all the ore bodies which 
are extensive and rich have been formed at the intersection of the Silver 
fault with crosscutting faults, chiefly those which belong to the Della 
system. Along these intersections the shoots are extensive and continuous 
for long distances, while elsewhere both the Silver fault and the cross- 
cutting breaks are ordinarily barren. In Aspen Mountain the best ore is 
found, both in dolomite and in blue limestone, at the intersection of small 
cross faults with the Aspen and Contact faults. In Tourtelotte Park the 
richest ore has been found in certain nearly vertical shoots which cut the 
Contact fault and run up continuously, in many cases, through the whole 
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