258 THEORY of the EARTH. 



WE are thus led to iuppofe, that the power of heat and ope- 

 ration of fuiion muft have been employed in confolidating 

 ftrata of loofe materials, which had been collected together and 

 amafled at the bottom of the ocean. It will, therefore, be pro- 

 per to confider, what are the appearances in confolidated ftrata 

 that naturally mould follow, on the one hand, from fluidity 

 having been, in this manner, introduced by means of heat, 

 and, on the other, from the interftices being filled by means of 

 folution ; that fo we may compare appearances with the one and 

 other of thofe two fuppofitions, in order to know that with 

 which they may be only found confident. 



TE confolidation of ftrata with every different kind of fub- 

 ftance was found to be inconfiftent with the fuppofition, that 

 aqueous folution had been the means employed for this pur- 

 pofe. This appearance, on the contrary, is perfectly confident 

 with the idea, that the fluidity of thefe bodies had been the ef- 

 fect of heat ; for, whether we fxippofe the introduction of fo- 

 reign matter into the porous mafs of a flratum for its confoli- 

 dation, or whether we fhall fuppofe the materials of the mafs ac- 

 quiring a degree of foftnefs, by means of which, together with an 

 >mmenfe compreflion, the porous body might be rendered folid ; 

 the power of heat, as the caufe of fluidity and vapour, is equal- 

 ly proper and perfectly competent. Here, therefore, appear- 

 ances are as decidedly in favour of the lafl fuppofition, as they 

 had been inconfiftent with the firft. 



BUT if ftrata have been confolidated by means of aqueous 

 folution, thefe mafTes fhould be found precifely in the fame 

 ftate as when they were originally depofited from the water. 

 The perpendicular fection of thofe mafles might ihew the com- 

 preflion of the bodies included in them, or of which they are 

 compofed ; but the horizontal faction could not contain any fe- 

 paration of the parts of the ftratum from one another. 



IF, again, ftrata have been confolidated by means of heat, 

 acting in fuch a manner as to foften their fubftance, then, in 



cooling, 



