198 Scrope — Origin of Yalleys. 



But, of course, while ' Eain and Eivers ' were doing so mucli in 

 tlie neighbourhood of the volcanos of Central France, they were not 

 idle elsewhere, in the Alps, or the Pyrenees, in the British isles, in 

 fact wherever land lay exposed to their influence above the protect- 

 ing surface of the great waters.^ That the abrading action of the 

 sea-waves may have in many instances widened many of the larger 

 valleys to which it obtained access during temporary depressions of 

 the land, I am far from denying. But I am confident that this last 

 doctrine is pushed much too far by those who find a sea-worn cliff 

 in every steep hill bordering a valley.^ Why there is scarcely a 

 river to be found anywhere, that is not now engaged, in one or more 

 parts of its course, in undermining its hilly banks on one side or the 

 other, and fashioning them into cliff-like bluffs. The most pregnant 

 example of this kind with which I am acquainted is the valley of the 

 Moselle, where it traverses the high plateau of Devonian Slate-rock 

 above Treves. Here the entire valley serpentines in repeated curves, 

 some of them almost completing the circle, so that after a sweep of 

 twelve or fifteen miles the river returns to within a few hundred 

 feet of the same spot ; and a person may stand on the high isthmus 

 separating the two extreme points of the curve, and fling a stone 

 into the water on either side five or six hundred feet beneath him. 

 In all these curves the concave bank is a steep bluff which the 

 sti'eam is still engaged in undermining ; the convex one, a sloping 

 fan-shaped pebble-strewn talus, just as is seen, on a smaller scale, 

 in the similar windings of many streams through an alluvial plain. 

 And it is evident that the erosive action of the river-floods has alone 

 in the one case as in the other excavated the entire channel. The 

 action of the sea, even if it could be supposed to have penetrated at 

 any epoch the valley of the Moselle (of which there exists no sign) , 

 could never have eaten out the slate-plateau in these symmetrical 

 and regular curves. 



" The time that must be allowed for the production of effects of 

 this magnitude by causes so slow in their operation is indeed immense. 

 But it is now generally recognised by geologists that the periods 

 which to our narrow apprehension, and compared with our ephemeral 

 existence, appear of incalculable duration, are but trifles in the calen- 

 dar of Nature. Every step we take in geological pursuit, forces us 

 to make almost unlimited drafts upon antiquity. The leading idea 

 which is present in all our researches, and which accompanies every 

 fresh observation, the sound which to the ear of the student of natm-e 

 seems continually echoed from every part of her works, is Time ! — 

 Time!— Time! "3 



^ See Dr. EuMdge's paper on the Denudatioai of South Africa. Geol. Mag., 

 vol. iii. p. 88. 



- And, I may add, Raised Beaches in the plough-worn lynchets of our downs. 

 As weU see them in the vine-terraces of the banks of Ehine or Moselle ! See 

 Mackintosh, Geol. Mag., vol. iii. pp. 69 and 155. 



3 Geology of Central France. Ed. 1827. It is very satisfactory to me to find 

 (see the last number, April, 1866, of the Journal of Science, p. 208) that ray old 

 friend and fellow labourer in the Volcanic Department of Geology, Dr. Daubeney, 

 has acknowledged at last the correctness of the views I was led to entertain upon 



