MOUNTAINS 305 
monly, the upturned edges of hard layers, which 
because of their hardness, stand above the general 
level. The ridges extend in a linear manner, having 
greater length than either height or width. So a real 
mountain range is made of various ridges. 
In a range there are also areas, usually with bases 
more or less circular, which rise above the general 
Fic. 178. 
A mountain ridge, near Banf, on the Canadian Pacific. 
level, forming mountain peaks (Figs.. 103 and 179). 
These are commonly composed of some harder rock 
than the remainder of the mountain, and because of 
this, have. resisted erosion more firmly than the rest. 
Or the peak may have been originally built to a 
ereater height than the surrounding range, or it may 
be a divide area, where denudation has produced 
less effect. 
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