Effects of Heat modified ly Compression. 205 



striking manner, are unknown to many persons best capable 

 of appreciating their value. The most important, and at the 

 same time the most astonishing truth which we learn by any 

 geological observations, is, that rocks and mountains now 

 placed at an elevation of more than two miles above the level 

 of the sea, must at one period have lain at its bottom. This 

 is undoubtedly true of those strata of limestone which con- 

 tain shells; and the same conclusion must be extended to 

 the circumjacent strata. The imagination struggles against 

 the admission of so violent a position, but must yield to the 

 force of unquestionable evidence ; and it is proved by the 

 example of the most eminent and cautious observers, that 

 the conclusion is inevitable *. 



Another question here occurs, which has been well treated 

 by Mr. Playfair. Has the sea retreated from the mountains? 

 or have they risen out of the sea ? He has shown that the 

 balance of probability is incomparably in favour of the latter 

 supposition; since, in order to maintain the former, we must 

 dispose of an enormous mass of sea, whose depth is several 

 miles, and whose base is greater than the surface of the 

 whole sea. Whereas the elevation of a continent out of a 

 sea like ours, would not change its level above a few feet ; 

 and even were a great derangement thus occasioned, the 

 water would easily find its level without the assistance of 

 any extraordinary supposition. The elevation of the land, 

 too, is evinced by what has occasionally happened in vol- 

 canic regions, and affords a complete solution of the con- 

 tortion and erection of strata, which are almost universally 

 admitted to have once lain in a plane and horizontal posi- 

 tion. 



Whatever opinion be adopted as to the mode in which 

 the land and the water have been separated, no one doubts 

 of the antient submarine situation of the strata. 



An important scries of facts proves that they were like- 

 wise subterranean. Every thing indicates that a great quan- 

 tity of matter has been removed from what now constitutes 

 the surface of our globe, and enormous deposites of loose 



• Sausnire, Vbyagti dans hs Alpn, torn. ii. p. 99 — 104. 



fragments. 



