40 THEORY OF THE EARTH. 



skeleton, or, as it were, the rough frame-work of 

 the earth. 



The sharp peaks and rugged indentations which 

 mark their summits, and strike the eye at a great 

 distance, are so many proofs of the violent manner 

 in which they have been elevated. Their appear- 

 ance in this respect is very different from that of 

 the rounded mountains and the hills with flat sur- 

 faces, whose recently formed masses have always 

 remained in the situation in which they were 



quietly deposited by the sea which last covered 



TL 



them. 



These proofs become more obvious as we ap- 

 proach. The valleys have no longer those gently 

 sloping sides, or those alternately salient and re- 

 entrant angles opposite to one another, which 

 seem to indicate the beds of ancient streams. They 

 widen and contract without any general rule ; their 

 waters sometimes expand into lakes, and sometimes 

 descend in torrents; and here and there the 

 rocks, suddenly approaching from each side, form 

 transverse dikes, over which the waters fall in ca- 

 taracts. The shattered strata of these valleys ex- 

 pose their edges on one side, and present on the 

 other side large portions of their surface lying ob- 

 liquely; they do not correspond in height, but 

 those which on one side form the summit of the de- 

 clivity, often dip so deep on the other as to be alto- 

 gether concealed. 



