ASPEN SPECIAL MAP. 83 
date than the regional foldmg. This uplift was due to local disturbing 
forces, and seems to have been contemporaneous with the initiation of the 
first fault systems. 
Fourth. There originated a system of faults having a general north- 
south trend and in general a nearly vertical dip. The greatest of these 
is the Castle Creek fault, and from this toward the east the parallel faults 
grow successively less in importance till the system dies out before 
reaching East Aspen Mountain. All of these faults are characterized by 
having their greatest development on Aspen Mountain, from which point 
they diminish in throw to the north and to the south. Several of them 
have very great displacement, and they all were almost entirely devel- 
oped previous to the deposition of ores, for it is along them that much of 
the ore has been found. ‘This system is, however, of younger age than the 
Silver system of faults, since it faults this latter system in the same way 
that it does the inclosing rocks. To the Aspen Mountain system, also, 
belong certain nonpersistent cross faults, which, however, have often 
considerable throw. Such are the faults at the north end of West Aspen 
Mountain, and those of the Bonnybel and Chloride system. Their prob- 
able identity in age with the main north-south faults is shown by the fact 
that they also are highly mineralized. It appears probable that this 
system of mainly north-south premineral faults was developed at about 
the same time that the doming-up of the rocks on Aspen Mountain 
occurred, and that the phenomena of faulting and folding are both 
manifestations of the same upthrusting power. 
Fifth. The faulting which has thus been described apparently con- 
tinued during and after the period of ore deposition. The Della system of 
faults on Smuggler Mountain evidently existed previous to the period of ore 
deposition, for it is along these faults, at their junction with the Silver, that 
much if not most of the ore on Smuggler Mountain has been deposited. 
The barrenness of. much of the slipping planes, however, and the fact that 
along these barren planes there are often fragments of hard ore found in 
the breccia, show that much of the movement has gone on subsequent to 
the ore deposition; and, indeed, it is probable that the faults in some cases 
have had their main development since that period. There is also evidence 
that the movement along these faults is still going on, this evidence being 
derived from the deformation of mine workings. These faults, which have 
