GLACIATION IN THE TELLURIDE QUADRANGLE 715 
sandstone, and shale. Many of these bowlders, even of the hard 
varieties such as diorite, are well rounded. It is noteworthy that 
San Juan bowlders are absent. Striated bowlders were found in 
only one of the areas mapped, that is in the area lying east-west 
about three-quarters of a mile north of east from Diamond Hill. 
The deposit on Diamond Hill ranges up to ro or 20 feet in thickness; 
the thickness at other points is not easily estimated, but may reach 
Fic. 15.—Diamond Hill elevation 10,100 feet. Looking northeast from elevation 
9,400 feet. Glacial drift of the earlier epoch covers the northern (left-hand) end of 
this mesa. : 
50 feet for the area three-quarters of a mile north of east of 
Diamond Hill. 
These deposits are classed as older drift because of (1) their 
position, in disconnected patches on points ranging up to 500 feet 
higher than the nearest drift of the more recent epoch; and (2) 
their composition, including prominent bowlders of Potosi rhyolite 
which is not characteristic of the more recent drift. 
