290 On the Physical Geography of the Alps, 



also of the mountain ranges, and such a frequent regularity 

 in the distribution of elevations % How could it be possible 

 for an Alpine valley to be excavated by such means from 

 the summit of Mont Blanc, down to a depth of 3000 Fr. feet 

 (French) ? 



With regard to the sudden expansion of the basins, charac- 

 terising the transverse valleys of the Alps, it is stated (p. 200), 

 that this could not have been the result of violent outbursts 

 of water ; it not being possible for water to have collected in 

 great masses where no dam was present to restrain it ; and, 

 if a dam had once existed, it could only have been cut through 

 by a deep gap, and not removed entirely, without a trace 

 being left through its whole extent. And at p. 207, in con- 

 sidering how far great local collections of water may have 

 been concerned in the formation of these valleys, the author 

 observes, that were their figure due to this form of aqueous 

 agency, they must be regarded as cauldron-shaped cavities, 

 that gradually become filled with debris, and now offer 

 levelled surfaces. But this view is decidedly opposed not 

 only by the fact of the very frequent protrusion of the under- 

 lying rock, but by the usual occurrence of the rock surface at 

 the slight depth of 10-12 feet (French) beneath the super- 

 ficial gravel. That the basin or trough-like forms especially, 

 that is, the retreating of the sides of the valley on both sides, 

 cannot have been effected by the presence of a lake, is suflB- 

 ciently clear. We would otherwise confound the effect with 

 the cause. The question, whether collections of water have 

 generally occupied these cavities, is easily answered in most 

 cases. We usually find here smaller gravel beds, that by 

 their equal distribution are decidedly shewn to have been 

 deposited in standing waters. The inequalities of the valley- 

 bottoms may, indeed, in many cases be sufficient cause for 

 this ; but sometimes (for example, near Lengenfield) the form 

 of the ravine immediately following, and the depth of the 

 erosion of the river channel, shew that here a stopping of 

 the 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 configuration of the whole district, and in the ori- 

 ginal mode of the formation of the valleys. This is the more 



