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SCENERY OF SWITZERLAND. 
CHAPTER VIII. 
DIRECTIONS OF RIVERS. 
The general direction of the river-courses in any 
country is determined in the first instance by the 
configuration of the surface at the time of its be- 
coming dry land. The least inequality in the 
surface would affect the first direction of the 
streams, and thus give rise to channels, which would 
be gradually deepened and enlarged. They are, 
however, in many cases materially modified by sub- 
sequent changes of relative level, and by the results 
of erosion, which acts of course much more rapidly 
on some strata than on others. It is as difficult, 
however, for a river as it is for a man to get out of 
a groove. 
If we imagine a district raised in the form of a 
regular dome, the rivers would radiate from the 
summit in all directions. The lake district in the 
north of England; the Plateau of Lanneme-zan in 
the south of France, and the Ellsworth Arch in the 
Henry Mountains,* offer us approximations to such 
* See Gilbert, Geology of the Henry Mountains . 
