GLACIATION IN THE TELLURIDE QUADRANGLE 631 
shale traversed by dikes of igneous rocks.- The shale is in places 
eroded into deep gullies (Fig. 13), leaving bare, gray slopes; in 
other places landsliding has occurred, resulting in ridges lying 
Fic. 13.—East branch of Kilpacker Creek; eroded, bare Mancos shale in center; 
elevation about 11,300 feet. Lizard Head Peak in background. The eroded floors of 
cirques with shale as the underlying formation contrast strongly with the roches 
moutonnées of cirques formed in harder rocks. 
approximately parallel to the slope, inclosing undrained depressions. 
The two small cirques near Mt. Wilson have a steep gradient, and 
