OF THE EARTH. 487 



here remark that this offers an explanation of the 

 modes in which deluges might have hecn produced,, 

 in addition to the partial torrents consequent on the 

 elevations of strata in particular places. The sub- 

 mersion of the dry land over any portion of [the earth, 

 is a deluge ; and, thus we possess many causes, inde- 

 pendently of the much discussed Historical one, for 

 explaining the cases of alluvial formations. 



If cosmogonists have invented systems of depres 

 sion, causing an imaginary crust of the earth to sink 

 into imaginary abysses, they have been borne out by 

 geological facts, of which they knew not the existence, 

 though their theories were wrong. Too much ridi- 

 cule has been cast, by recent writers, on the depres- 

 sion of strata as an engine of geological theory ; partly 

 because the mode of explanation was wrong, and 

 partly, because it was applied to the solution of cases 

 which it would not solve. But if the elevation of 

 strata is proved, so also is the depression ; while if I 

 am right in the preceding remarks, the one implies 

 the other. And if I have succeeded in showing that 

 this is true of the case just examined, it is not less 

 probable, as I already hinted, that every great revo- 

 lution of the earth has possessed a similar character. 

 Thus the several disclosures of land have been at- 

 tended by a conversion of land into sea : or, in a geo- 

 graphical sense, the results have been interchanges, 

 to a certain degree, between the places of sea and 

 land. But I leave this to the consideration of geologists. 



It will not affect these views of this interval of revo- 

 lution, to know that in the Alps, or in any other place, 

 the magnesian limestone and red marl are highly in- 

 clined or even parallel to the inferior strata. All that fol- 

 ows is, what is here often indicated, that such revolu- 

 tions may not have been simultaneous nor exactly simi- 

 lar, nor even the same in number, in every part of the 



