496 ON THE SUCCESSIVE FORMS 



We have reason to think,, that under each of these 

 successive states, the earth must have possessed dif- 

 ferent characters, and, that its geographical distribu- 

 tion was different in each ; but we have no reason to 

 believe that its rocks presented any other varieties 

 than those which we now see. The primary strata 

 resemble those which immediately preceded them, as 

 is proved by the nature of the included fragments; 

 if we cannot carry this comparison further backwards. 

 The greatest change of character takes place between 

 the primary and the secondary, but the analogies 

 continue; while I have formerly accounted for the 

 differences that do exist. That every former state of 

 the earth contained, like the present, alluvial soils, is 

 certain, because that is implied in the formation of 

 submarine alluvia. 



Similar conditions as to an atmosphere and all the 

 consequences which it implies as connected with 

 an earth, also follow: and, that the lakes, of one state 

 at least, were of great size and number, is proved by 

 the formation of the coal deposits. But if the sea and 

 the dry land were differently distributed, there is no 

 reason to think that the absolute quantity of water 

 has varied at different periods, since there are no phe- 

 nomena that render it necessary or probable; as there 

 are many that render it improbable or impossible. 

 A larger portion of water needs not be assumed 

 for the solution of the materials of rocks, because they 

 are insoluble in any quantity that could have existed 

 consistently with the order of the planetary system ; 

 as the existence of such an imaginary quantity is che- 

 mically improbable, because we know of no means by 

 which it could have been converted into other sub- 

 stances, and because nothing is annihilated. Nor would 

 the alternate elevation and depression of water, even 

 could it be admitted, account for the geological ap- 

 pearances of the successive orders of strata; while 



