60 GEOLOGY OF ASPEN MINING DISTRICT, COLORADO. 
considerably steeper. Most of the decrease, however, is due to the cross 
faulting which has been noted. West Aspen Mountain is really an isolated 
block, included between the Pride fault, Castle Creek fault, and Mary B. 
fault. The northern end of West Aspen Mountain is also the northern end 
of this upthrust block, which comes to an end suddenly at the meeting of 
the Mary B. and the Pride faults. The whole of this block is enormously 
elevated above the surrounding formations, but the elevation is much 
greater at the southern end than at the northern, which is due to the steep 
northern pitch of the beds on the northern point of West Aspen Mountain. 
In this latter locality dragging of the beds has produced a series of east- 
west faults, which run across from the Pride fault to the Mary B. or the 
Jastle Creek fault. 
Pride fault. —This fault receives its name from its occurrence in the Pride 
of Aspen mine, the most northern point at which it has been located. Here 
the fault has a downthrow to the east of about 2,000 feet, thus bringing down 
on the east side the basal micaceous limestone of the Maroon, while on the 
west side is the Silurian dolomite. From this point the fault runs straight 
south through the Igneous tunnel, then through the Sixty-six shaft and just 
west of the Broadway tunnel, and so to the very summit of the hill, where 
it passes into granite on both sides and can not be traced farther. In the 
Igneous tunnel the fault brings the Weber shale on the east against the 
eranite on the west. Near the Broadway tunnel there is blue limestone 
belonging to the Leadville formation on the east side of the fault, with 
eranite on the west side. A short distance north of the Broadway the main 
Pride fault splits into two. The course of the more westerly of these two 
is nearly continuous with that of the main fault previous to dividing. This 
branch may, therefore, be still called the Pride fault, while the eastern 
branch, which deviates from the main fault a little in trend at the poimt of 
parting, but immediately swings round and runs parallel with it out of the 
area mapped and for a long distance across the Tourtelotte Park area, may 
be called the Saddle Rock fault, from its passing close by the Saddle Rock 
shatt in Tourtelotte Park. The effect of this division is to apportion the dis- 
placement of the single fault between the two derived faults. In Section A, 
where there is only a single fault, its throw is shown to be about 2,000 feet. 
In Section B, however, it is considerably less, while the Saddle Rock fault, 
which here comes in to the east of the Pride fault proper, has a throw of 
