Alpine Valleys and Alpine Lakes. 101 



such an effect has been produced is constantly exhibited on a 

 small scale in the natural sections that abound throughout the 

 Alps, wherein the existence of unconformable flexures is shown 

 not to lead to the formation of hollows in the interior of a con- 

 torted mass of rock. 



Another objection of a general character is derived from the 

 existence of large portions of the earth's surface which exhibit no 

 traces of considerable flexure, although the hypothesis requires 

 us to admit the continued action, during an immense period of 

 time, of forces competent to cause vertical disturbance. This 

 objection has been partly anticipated in the preceding pages. 

 It has been shown that at the time when the existing inequalities 

 of the surface began, some adjoining regions may probably have 

 escaped displacement, except a moderate amount of lateral shift- 

 ing towards the area of disturbance ; and it has been remarked 

 that a mountain district, once formed, would probably continue 

 to receive new flexures and thereby relieve the pressure on the 

 adjoining areas. Furthermore, in reference to certain districts 

 where very ancient sedimentary rocks appear to have remained 

 nearly undisturbed, it is not impossible that overlying and more 

 contorted strata may have been removed by denudation, and that 

 the earlier strata may have partly escaped flexure for the reason 

 already pointed out, viz. that they in some measure kept pace 

 with the rate of cooling of the deeper portions of the crust. 



The objections apparently most formidable, and of which I do 

 not doubt that a numerous array may be adduced by men so well 

 versed in the local geology of the Alps as M. Desor and Professor 

 Ramsay — not to name others whose views I may controvert — 

 rest upon the apparent discordance between the stratification of 

 the sedimentary formations, and the flexures indicated by the 

 present relief of the surface. I have no doubt that there are 

 many facts apparently opposed to the views here advanced which 

 I should find it difficult or impossible to explain i but I would 

 observe that the problems raised are of extreme complexity; and 

 if I am right in believing that the present conformation of the 

 Alps is the complex sum of the operation of forces of compression 

 in various directions, and under varied conditions, through an 

 enormous period of geological time, I am entitled to assume 

 that the unravelling of so tangled a network of causation must 

 be a matter of all but insuperable difficulty. It will be obvious 

 that, in studying the relations of the stratification in successive 

 formations, we have to determine the probable condition of the 

 surface at the time when each was deposited, and the various 

 flexures which it has since undergone, which would differently 

 modify the disposition of the beds according as they led to frac- 

 ture, or bent the mass without breaking its continuity. Add to 



