258 Outlines of Geology . 



least of many of them, and observe that the same strata in the 

 same position, constitute the hills that bound them, we shall have 

 little reason to doubt that they have once been continuous, and 

 that the intervening portion has been removed. Some cases of 

 this kind have already been pointed out (see Vol. XIX. pp. 89 — 

 90) ; but there are others yet more decided, and upon a much 

 larger scale, as applying not to valleys only, but to the separation 

 of islands and continents. Look, for instance, at the two sides 

 of the English Channel, and the same strata, with the same pecu- 

 liarities, are found upon its opposite shores : shall we then disbe- 

 lieve iu the former continuity of these strata ? Or when we dis- 

 cover the coast of Norway exhibiting the stratification of the 

 Orkneys ; Majorca composed of the same materials as Minorca ; 

 the geological analogy of Corsica and Sardinia ; that of the oppo- 

 site shores of the Gulf of Venice, and many other analogous cases, 

 shall we be inclined to doubt the removal of the once intervening 

 matter ? Shall we not read in these correspondences, the list of 

 which might be much extended, the former non-existence of the 

 intervening chasms, let them be valleys, or rivers, or arms of the 

 ocean ? and shall we not have disproved the original existence 

 of, or contemporaneous formation of the valley, and may we not 

 reasonably conclude, that as the irregularities of valleys depend 

 upon the relative hardness and destructibility of the materials 

 that form their sides, from the nature of their soil, from the di- 

 rection of their ravines, and from some of the other facts that I 

 have already observed upon, that water has been the great agent 

 in effecting these excavations, and that certainly the mountainous 

 protuberances of the globe are not the invariable effect of volca- 

 noes ; that valleys have not been formed by earthquakes ; and 

 that mountains are not accumulations of sand and of mud collected 

 by submarine whirlpools, nor great crystalline shoots, as certain 

 German and French geologists would insist. 



But if we revert to the once even and regular state of 

 the earth's surface, and admit that impetuous torrents of water 

 have been chiefly concerned in carving out its irregularities, 

 where are we to look for the origin of these torrents, or how are 

 we to account for the gigantic effect which they have left behind ? 



