GLACIATION IN THE TELLURIDE QUADRANGLE 619 
above the junction with Howard Fork is steep-sided, V-shaped, 
with outcropping rock on the east, and slopes covered with talus or 
soil on the west which, in places, supports a growth of aspen. This 
forest and the fresh accumulations of talus east of San Bernardo 
Mountain conceal such signs of glaciation as may have been 
present, except for occasional patches of bowlders, which, from their 
rounded and subangular forms and the variety of kinds present, 
are clearly of glacial origin. 
The thickness of the ice in the neighborhood of Trout Lake and 
in the valleys above was probably on an average not more than 300 
to 400 feet, with a possible maximum at some points of 800 feet. 
VALLEY OF BILK CREEK 
The upper part of the valley of Bilk Creek is double headed, 
with three small tributary cirque-valleys on the eastern side. 
Except for the small amount of loose material along the stream in 
the lower part, and the usual talus accumulations near the upper 
margins, this part of the valley is well cleaned out. Above 11,000 
feet in elevation along the stream draining Bilk basin roches mouton- 
nées occur at frequent intervals. At 11,200 feet‘is a small alluvial 
flat; below this the stream flows in a channel 100 feet deep at some 
points. At 11,800 feet and at 12,200 feet in Bilk basin, striae on 
rock in place have a direction approximately parallel to the course 
of the stream. At 12,000 feet, and at 12,700 feet, lakes or ponds 
are found in rock basins. Talus is abundant at the sides and heads 
of Bilk basin, and on the south side at 11,700 to 11,900 feet is a 
rock stream. From 11,000 to 11,500 feet in elevation the valley 
of the south branch of the upper part of Bilk Creek has a more 
gentle gradient and the bottom is in places marshy. Farther up are 
roches moutonnées and the usual boundary of talus slopes and pre- 
cipitous rock walls. Abundant talus, partly overgrown with 
vegetation, flattened bottoms, and walls somewhat less precipitous 
than in typical cirques characterize the three cirque-valleys on the 
eastern side. 
Magpie Gulch and the cirque lying next to the north contain 
little direct evidence of glaciation; enough, however, is present to 
make their occupation by ice certain. Within the lower, forest- 
