GLACIAL PERIOD. 
23 
Some investigators have been inclined to 
explain the presence of boulders, moraines, 
drift, and the like phenomena by the action of 
water. But even if we could believe that rivers 
had brought along with them such masses of 
rock, and deposited them where they are now 
found, the regularity in the distribution of the 
materials disproves any such theory. In the 
lateral moraines of the Lake of Geneva we 
have a striking illustration of this apparently 
systematic division of the loose materials. The 
northeastern moraines of that glacial basin 
contain rocks belonging exclusively to the 
northern side of the valley of the Rhone, while 
the moraines on the southern shore of the lake 
consist of rocks belonging to its southern side. 
Indeed, rivers, so far from building up mo¬ 
raines, have often partially destroyed them. 
We find various instances of moraines through 
which a river runs, having worn for itself a 
passage, on either side of which the form of 
the moraine remains unbroken. In the valley 
of the Rhone there are villages, as, for in¬ 
stance, Viesch, built on such moraines, with 
the river running through their centre. 
If we need further confirmation of the fact 
