132 GEOLOGY OF ASPEN MINING DISTRICT, COLORADO. 
Sectionc.—This section shows at the outcrop of the contact of granite 
and Cambrian quartzite a slight flattenmg of dip, but the flatter beds 
above have been removed by erosion. Above the Cambrian there lies 
nearly the whole thickness of the Silurian, but, as in the previous section, 
the dolomite rests in outcrop against the Weber shales. The Parting 
Quartzite does not outerop, but in the St. Joe shaft, which cuts the Silver 
fault, it was discovered underground. The peculiar curve of the 
Silver fault at this point, as represented on the section, and the manner in 
which it cuts across the upturned strata, have actually been developed in 
the mine workings. The contact of Weber and Maroon comes under the 
drift-filled Hunter Creek Valley, so that the first outcrops on the north side 
are of Maroon sandstones. 
The section has been continued beyond the limits of the Hunter 
Park map across the northwest corner of the Aspen special district and a 
little up the side of Red Mountain, so as to give a more general idea. The 
whole of this mountain side is in the uniformly dipping Maroon beds. 
THE ASPEN DISTRICT MAP. 
OUTLINE OF STRUCTURE. 
In order to combine and to bring out the connection between the 
special parts of the general mining region which have been described in 
the 800-foot maps, a single large map was constructed, covering the areas 
of these smaller ones and furnishing some additional information. In 
reducing the 800-foot maps to the half-mile scale many of the details were 
omitted, and the structure was thus generalized, but in all cases the 
distinctive features were carefully preserved. In the complicated areas this 
was especially necessary, as, for example, in Tourtelotte Park, where the 
faults are so close together that they can not well be represented on the 
scale of half a mile to the inch in such a manner as to be intelligible. A 
variation in the plan of this map from that of the maps on the 800-foot 
scale is the omission of the Recent or Glacial formations. In the space 
between Aspen and Smuggler mountains, where the valley is filled with 
deep glacial material, the connection between the rocks on the two sides 
of the valley is not always well understood by the mining population. As 
shown in this map, the relation of the two is not very difficult to conceive, 
the apparent great difference being due to the uplift of the strata on Aspen 
