GLACIATION IN THE TELLURIDE QUADRANGLE 523 
11,000 feet separates the cirque from the forest-covered portion of 
the valley below. Below the precipice, well-developed lateral 
moraines extend on either side of the valley down to about 10,000 
feet in elevation. Below this point to the edge of the valley of the 
San Miguel, a distance of nearly a mile, the morainal deposits 
consist of an irregular grouping of hillocks, with a few fragments of 
ridges transverse to the valley. From the abundance of the 
moraines in the lower part of the valley, and from their arrangement 
partly as ground moraine and partly as recessional moraines, it 
seems probable that but little ice from the valley of Eder Creek was 
added to the glacier in the San Miguel valley. 
In the valley of the east fork of Eder Creek, a glacier less than 
a mile in length existed in the later stage of glaciation. Above 
11,000 feet in elevation the valley shows the rounded forms due to 
the effect of passing ice wherever rock in place outcrops in pro- 
jecting ledges or points; back of the more level, rounded slopes are 
the precipitous faces of the bounding walls, with steep talus slopes, 
overgrown, in this valley, for the most part with scanty vegetation. 
Between 10,500 and 11,000 feet in elevation, the stream draining 
this tributary valley has a very steep-walled, V-shaped channel. 
In the bottom of the channel, and at some places for ro feet to 20 
feet up the sides, the Telluride formation outcrops; lying on the 
Telluride formation is glacial débris 30 to 4o feet thick, containing 
bowlders up to 4 feet in diameter, some of which are well striated. 
The thickness of the ice in the valley of Eder Creek does not 
seem to have exceeded a maximum of 200 to 300 feet. 
VALLEY OF MILL CREEK 
The main valley of Mill Creek, heading south of Gilpin Peak, is 
broadly U-shaped above about 10,500 feet in elevation, becoming 
broader toward the upper end. Knobs of rock in place at frequent 
intervals show the rounded surfaces of roches moutonnées, but in 
most places no striae could be found. The surface is weathered — 
rough, or broken up, as if by changes of temperature, into small 
fragments. Grooves are found at about 11,100 feet elevation on 
the left bank of the stream, with direction S. 43° W. In the 
bottom of the valley some areas are almost flat; at a few points in 
