THEORY of the EARTH. 253 



that this had been executed by the operation of heat or fimple 

 fufion. 



THE proof I give is this, That befides the general conforma- 

 tion of thofe hard bodies, fo as to be perfectly adapted to each 

 other's fhape, there is, in fome places, a mutual indentation of 

 the different pieces of gravel into each other ; an indentation 

 which refembles perfectly that junction of the different bones 

 of the cranium, called futures, and which muft have necefTarily 

 required a mixture of thofe bodies while in a foft or fluid Mate. 



THIS appearance of indentation is, by no means, fingular or 

 limited to one particular fpecimen. I have feveral fpecimens of 

 different marbles, in which fine examples of this fpecies of 

 mixture may be perceived. But in this particular cafe of the 

 Spanifh pudding-flone, where the mutual indentation is made 

 between two pieces of hard {tone, worn round by attrition, 

 the foftening or fufion of thefe two bodies is not fimply render- 

 ed probable, but demonllraied. 



HAVING thus proved, that thofe ftrata had been confolidated 

 by fimple fufion, as propofed, we now proceed to {hew, that 

 this mineral operation had been not only general, as being 

 found in all the regions of the globe, but univerfal, in confoli- 

 dating our earth in all the various degrees, from loofe and in- . 

 coherent {hells and fand, to the moft folid bodies of the filice- 

 ous and calcareous fubftances. 



To exemplify this in the various collections and mixtures of 

 fands, gravels, fhells and corals, were endlefs and fuperfluous. 

 I {hall only take, for an example, one fimple homogeneous body, 

 in order to exhibit it in the various degrees of confolidation, 

 from the ftate of fimple incoherent earth to that of the mod fo- 

 lid marble. It muft be evident that this is chalk j naturally a 

 foft calcareous earth, but which may be alfo found confolidated 

 in every different degree. 



THROUGH the middle of the ifle of Wight, there runs a 

 ridge of hills of indurated chalk. This ridge runs from the 



ifle 



