378 Mr. A. C. Ramsay on the Excavation of 



their general contours only have been thoroughly moulded and 

 modified. During a late visit to the Alps I obtained, by help of 

 that distinguished geologist, Mr. Gastaldi of Turin, some import- 

 ant evidence on the subject. 



No true geologist is likely to assert that these valleys have 

 been mainly ^cooped out from end to end by ice, for the reason 

 that, since the disappearance of the ice, running water, in the for- 

 mation of gorges, &c, has comparatively effected so little. Given 

 sufficient time, and, as old Ray long ago inferred, any amount of 

 degradation may be produced by rain and running water. The 

 Alpine streams have doubtless flowed in their present channels 

 for long, and, compared with the depth of the valleys, have done 

 but little. Long, however, is a comparative term, and in this 

 instance it may represent a very brief period compared either 

 with the length of the great glacial epoch, or with that which, pre- 

 ceding it, came after the disturbance of those Miocene rocks that 

 form so important a portion of the Alps, and the right understand- 

 ing of which disturbance is an essential element of the question. 

 For obvious reasons (which it would take long to detail, but 

 which every geologist will appreciate) it is evident that the period 

 that has passed between the disappearance of the great glaciers 

 and the present day is trilling compared with that which elapsed 

 between the close of the Miocene and the commencement of the 

 glacial epoch of geologists ; and also there is good reason for sus- 

 pecting that the great glacial epoch itself was longer than that 

 which has passed since the climate of the northern hemisphere 

 ameliorated. It is not therefore to be expected that the later 

 modifications of Alpine valleys produced by existing causes should 

 be commensurate to the old, for time is wanting. When we go 

 back to the epochs that followed the disturbance of the Swiss 

 Miocene rocks, we have to deal with periods so long, that (if the 

 style of reasoning of the greatest geologists and naturalists is 

 worth anything) the glacial and existing epochs united are tri- 

 fling compared with it ; for during those periods the mammalian 

 life of the world was renewed again and again, and the inverte- 

 brata of the seas, though as species far more enduring, were by 

 slow gradations almost all replaced; while since the commence- 

 ment of the " glacial epoch " it is more than doubtful if a single 

 species of marine mollusca has disappeared. There was there- 

 fore, after the disturbance of the Miocene rocks of the Alps, 

 ample time for enormous degradation by any existing cause. 



Let any one who doubts the wasting and erosive power of com- 

 mon atmospheric agents aided by running water, visit Auvergne 

 and the countries formed of solid rocks bordering the Rhine and 

 Moselle. Like the Alps, both of these regions have been above 

 the sea, at least, ever since the close of the Miocene epoch. Both 



