152 GUIDEBOOK OF THE WESTERN UNITED STATES. 
greater metamorphism (changes due to pressure or to heat) toward 
this mass of granite, and on this account do not bear a close resem- 
blance to those of the same age farther east. 
Beyond milepost 111, west of Oden (see sheet 21, p- 160), the valley 
between the Cabinet Range on the east and the Selkirk Range on the 
west is a broad plain. Down this great valley a glacier once forced 
its way from Canada past Bonners Ferry and extended many miles 
south along the route followed by the Northern Pacific to Spokane. 
On approaching Sandpoint the railroad skirts the extreme west 
end of Pend Oreille Lake, but in this part of the lake the shores are 
generally low, and the view is not so striking as that 
Sandpoint. obtained from Hope. From Sandpoint the moun- 
—— tain slope on the opposite (south) side of the outlet 
pis panies miles, Of the lake, by reason of its gentleness and smoothness, 
is so different from those generally seen along Clark 
Fork, although composed of the same kind of rock, that it calls for an 
explanation. This long ridge does not rise abruptly from the water 
level at its north end, like the mountain slopes on the other side of 
Pe ae 
FIGURE 32.—Profile of mountain slope east of Sandpoint, Idaho, Ice moved in the direction indicated 
by the arrow and scoured the slope smooth, 
the lake, but rises gradually to a height of 2,000 feet above the 
lake. The profile as seen from Sandpoint is represented in figure 
32. The explanation of the gentle slope is that the great glacier 
which once came down the valley from the north and which probably 
had a depth of more than 1,000 feet, passed far up on the slope of 
this mountain and possibly completely overrode it. This mass of 
ice, with its embedded rocky fragments, ground off all irregularities 
of the mountain side, leaving it a gently inclined slope from bottom 
to top. The direction of the moving ice is indicated on the diagram 
by the arrow. 
At Sandpoint the Great Northern and the Spokane & Interna- 
tional (Canadian Pacific) railways approach the Northern Pacific, 
but the Great Northern at its point of nearest approach is 2 miles 
from the lake and can not be seen from the train. 
South of Sandpoint the railway crosses the lower end of Pend 
Oreille Lake on a steel and concrete viaduct 4,769 feet long. From 
this viaduct may be obtained, if the day is clear, a comprehensive 
view of the mountains east of Pend Oreille Lake. The significant 
feature of this mountain mass is not its height or its ruggedness, 
