164 GEOLOGY OF ASPEN MINING DISTRICT, COLORADO. 
the general strike of the beds on East Aspen Mountain and throughout the 
rest of the district in general. They are not, however, at right angles to 
the strike of the beds in the main part of the Aspen Mountain area, for here 
the strike is variable, being altered from the usual direction by the influence 
of the Tourtelotte Park dome and by the Aspen Mountain syncline, which 
lies on the north face of the dome. Section D cuts across the center of the 
map and shows the westerly dipping strata on the east side of the syncline. 
It also cuts through the Tourtelotte Park dome, so that the formations as 
shown are not horizontal, but cross the uplift. In a section like this, which 
cuts the formations obliquely, the thicknesses are greatly exaggerated, and 
that of each bed varies with the changing local dips, the thickness bemg 
apparently greater as the beds become steeper. At the northern end is a 
thick covering of glacial drift, partly rearranged by water action, which 
covers the bed rock in the Roaring Fork Valley. The section follows 
continuously the line of workings which run along the Contact fault on 
Aspen Mountain from top to bottom, reaching from the Argentum-Juniata 
up to the Durant. Above the Durant the flattening of the beds indicates 
the appearance of a slightly different structure, and throughout Tourtelotte. 
Park the workings are not so large nor so continuous. The Silver fault 
is also continuously shown in the section, except in the northern part, 
where it runs into the glacial drift. Near the top of the hill are the 
Chloride and the Bonnybel faults, or, rather, the sheared wedge which 
these faults represent. These are shown near their junction with the 
Silver fault, and are very close together, forming practically a single 
fault. Beneath the drift on the north the two faults of the Ontario 
system are represented with very slight throw, dying out against the 
Silver fault. 
Pl. XXII is a general view of Aspen Mountain from the slopes of Red 
Mountain, looking south, showing the town of Aspen below. ‘The promi- 
nent squat hill at the foot of Vallejo Gulch which appears in Section A, 
Atlas Sheet XXVI, consisting entirely of loose material which the Home- 
stake deep shaft has penetrated, is shown to the right of the center of the 
picture. At the right is the edge of West Aspen Mountain and on the left 
is East Aspen Mountain. In the center is Spar Gulch, with Copper Gulch 
running into it, and near the top of the mountain is Tourtelotte Park. 
