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On the Physical Geography of the Alps. 371 
water-course had taken place. At all events, this kind of aqueous 
operation was only subordinate, and more deeply lying causes for 
the forms of these cavities must be sought for in the configura- 
tion of the whole district, and in the original mode of the forma- 
lion of the valleys. This is the more evident when we consider 
that many such basins are separated by precipitous depressions 
only, similar to terrace-like declivities, where there has been a 
perfect absence of any dams for the collection or restraint of water. 
In the longitudinal valleys, on reaching which the Alpine 
streams have already lost much of their force, considerable beds 
of gravel occur (p. 212), which have been cut through by the 
rivers. Here again river-erosion always appears of slight impor- 
tance in relation to the extent of these valleys. At the terminal 
Would have taken the shortest and straightest passage. It fre- 
quently happens also that a valley cuts through a lofty mountain 
nomena in the course of the Rhone 
The author considers, therefore, that although. ranmng ~ 
and atmospheric influences effect important changes In the earth’s 
Surface,* yet these operations have not been sufficient to give rise 
to the extensive series of Alpine valleys. — 
The real causes of the origin of these valleys appear to lie in 
associated with certain sinkings. 
The great basins found at the extremities of the valleys and - 
their wider developments, and repeated on a smaller scale on the 
or withdrawal [zuriick weichen |] of the masses. We <—_ here 
to observe, that the study of the valley-formation of the Alps can 
® A series of observations on erosion and weathering is given 
in chapter xii, of 
