VALLEYS. 
169 
tudinal valleys is due to the outcrop of layers of 
different hardness. 
A' 
In such cases the strata on the two sides are 
dissimilar; such valleys F 
are known in Switzerland 
as “Combes.”* 
Suppose a fractured 
anticlinal (A A' A", Fig. 38) e 
has been lowered by 
denudation to A C'A", 
and is drained by a stream 
running from C to E. If 
the strata are of different 
degrees of hardness, a 
soft stratum BE B" be- 
* In this country the word “Combe” is often used as syno- 
nymous with “cirque.” 
