different European Chains of Mountains. 297 



These distinct and abrupt variations in the nature of the suc- 

 cessive depositcs formed by the waters, are considered by geolo- 

 n-ists as the effects of what they have called the revolutions of' 

 the globe. Although it may seem difficult to say very precisely 

 of what these revolutions consisted, their existence is not the less 

 certain. 



I have spoken of the chronological order in which the dif- 

 ferent sedimentary formations had been deposited. I ought, 

 therefore, to say, that this order has been determined by fol- 

 lowing, without interruption, each kind of fonotiation into regions 

 where it could be positively determined, and over a great hori- 

 zontal extent, that a particular bed lay above another of a cer- 

 tain kind. Natural breaks in the strata, cliffs on the sea-shore, 

 common wells, artesian wells, and the cuts of canals, have 

 afforded great assistance in this determination. 



I have already remarked, that the sedimentary formations 

 are stratified. In plain countries, as might be expected, the 

 disposition of the beds is nearly horizontal. As we approach 

 mountainous countries, this horizontality generally alters ; and 

 upon the sides of the mountains, certain of these beds are 

 highly inclined, and even sometimes become entirely vertical. 

 Could the incHned sedimentary beds which are seen upon the 

 slopes of mountains, have been deposited in oblique or vertical 

 positions ? Is it not more natural to suppose, that they originally 

 formed horizontal beds, like the contemporaneous beds of the 

 same nature with which the plains are covered, and that they 

 were raised and turned up at the moment when the mountains 

 on whose sides they rest emerged .'' 



As a general proposition, it does not seem impossible that the 

 slopes of the mountains have been encrusted on the spot, and in 

 their present [)osition, by sedimentary deposites, since we daily 

 sec the vertical sides of vessels in which selenitic waters arc eva- 

 porated becoming covered with a saline layer, the thickness of 

 which goes on continually increasing ; but the question which 

 we have j)roposcd to oui .selves is not of so general a nature, for 

 all that we have to determine is, Whether the knoion sedimentary 

 beds have been thus deposited ? Now, this question may be an- 

 swered negatively, as I shall |)rove by two kinds of considera- 

 tions, totally difl'ticut iioui each other. 



