Origin of Valleys, 289 



in the serpentine windings of submarine currents ; whilst by 

 Pallas and Saussure, diluvial floods and erosion by streams 

 and by atmospheric precipitations, were regarded as partial 

 causes of the formation of valleys.* A local influence was 

 also ascribed to a partial overturning and breaking up of the 

 strata. t We must regard, he remarks, as erroneous the opi- 

 nions, that the manifold forms of valleys can be comprised in 

 one point of view, and that reduced, with few modifications, to 

 one cause. One easily understands how the great valleys exca- 

 vated by rivers continually eroding deposits, more or less soft 

 and destructible, are distinguishable from the ramifying 

 valleys of districts, which sometimes are widened out into 

 basins and sometimes contracted into narrow ravines. In 

 the latter, mountain masses of ever-varying profile rise on 

 both sides many thousand feet high, whilst in the former* 

 case, above the slopes on either side we meet w^ith nearly 

 horizontal plateaux, but slightly raised above the valleys. 



To remarks of this kind follow a series of descriptions of 

 basin-shaped hollows, transverse valleys, longitudinal valleys ; 

 these are followed by an account of mountain groups, moun- 

 tain ranges, and mountain summits. Having travelled much 

 in mountainous countries we think ,we understand the de- 

 scriptions of our author, but to those who have not enjoyed 

 such opportunities illustrative maps and plans are absolutely 

 required for the accurate comprehension of an Alpine country. 

 Supposing the descriptions to be well understood without 

 plans or maps, the following observations of Mr Schlagin- 

 tweit on the cause of the present forms of the valleys and 

 mountain groups and mountain ranges will prove interest- 

 ing to the reader. 



*♦ In treating of the Causes of the present forms of the 

 Valleys and Mountain-chains^ it is stated, that both erosion 

 by means of rivers and the disintegrating eff'ects of the at- 

 mosphere and its precipitations, can be considered as having 

 only subordinate influence on the formation of the Alpine 

 districts. How (it is asked) is it possible for erosion to have 

 eff^ected such equal declivities, not only of the valleys, but 



♦ Compare Voigt on the Formation of Valleys, 1791. 

 t D'Aubisson, Traits de Geognosie, 1. 1819. 



VOL. L. NO. C. — APRIL 1851. ' * 



