ASPEN MOUNTAIN. 163 
the west and then flattens again on nearing the bottom of the syncline. 
The slight thickness of blue limestone shown between the Silver and Con- 
tact faults has been well proved by mine workings. On the bottom of the 
section, below the Franklin shaft, the Aspen fault is represented as splitting 
off from the Silver fault, as in Section A. West of the Franklin shaft the 
bottom of the syncline is passed through. 
Section c.— The eastern end of Section C shows the tendency to anticlinal 
structure somewhat more strongly than Section B. Just west of the eastern 
end a cross fault of the Tourtelotte Park later system is cut. The beds 
have a comparatively gentle dip, almost identical with the slope of the hill. 
The section runs nearly parallel to the Bonnybel and Chloride faults, but, 
being vertical, while these faults have a southwest dip, it intersects them. 
The intersection with the Bonnybel is nearly horizontal, while that with the 
Chloride, which has a slightly differing trend, is more steeply inclined, and 
the two faults come together and run into the Aspen fault in the Durant 
mine. The section cuts through the Bonnybel mine, the Visino incline, 
and the Durant workings, where many of the data have been obtained. 
The steep easterly dipping fault not far west of Spar Gulch is one which 
is found near the mouth of the Visino tunnel, and in the Bonnybel mine a 
fault has removed the blue limestone from the small downtbrust block 
between the Bonnybel and the Chloride faults. A vertical dike of por- 
phyry, sending out small sheets, is also found in the Bonnybel and has 
been followed nearly down to the Parting Quartzite. This is shown contin- 
uing downward indefinitely and faulted by the Bonnybel fault, which seems 
in the mine to be of later date than the porphyry intrusion. The nature 
of the Aspen fault, as shown, has been well developed in its lower course 
by mine workings. It is represented as running into the Silver fault above. 
Between the Aspen fault and the next important fault to the west (the 
Schiller) there are a large number of minor breaks. Two of the chief of 
these, which are called by the mine managers the Schiller No. 2 and the 
Conomara, are known to be nonpersistent and are represented as uniting 
and dying out in the porphyry above. ‘The section cuts the block between 
the Schiller and the Sarah Jane faults just north of the outcrop of the 
contact of porphyry with the overlying shales. 
Section D—Section D, Atlas Sheet XXIX, is at right angles to Sections 
A, B, and C, Atlas Sheet XX VI, which have been drawn at right angles to 
