the valley itself has been worn out of the granite mass. 
The mountains on either side rise to the height of 2,000 
to 3,000 feet above the valley, and the glacial markings 
are visible 1,200 to 1,500 feet. The morainal deposits 
on the northwest side reach a height of 1,200 feet above 
the stream and form a sort of irregular terrace, which, 
when cut through by the little side-streams, show that it 
is made up of graval and bowlders much worn. In some 
instances there are well-worn cavities in the sides of the 
mountains, showing how the running water, in connection with 
a mass of rock, formed the cavity much as a "pot-hole" is 
made in our streams at the present time." 
(U.S . Geological Survey of the Territories, 1873, page 73) 
