$6 HISfORT of the S0CIE7T. 



work, of which, as often happens with the firft attempts to ge- 

 neralize, the plan was never executed, and may never have been 

 accurately digefted. 



From thefe {ketches it appears that the firft of the proportions 

 juft enumerated, viz. that a vail proportion of the prefent rocks 

 is compofed of materials afforded by the deftruction of bodies, 

 animal, vegetable, and mineral, of more ancient formation ; was 

 the firft conclufion that he drew from his obfervations. 



The fecond feems to have been, that all the prefent rocks 

 are without exception going to decay, and their materials de- 

 fending into the ocean. Thefe two proportions, which are the 

 extreme points, as it were, of his fyftem, appear, as to the order 

 in which they became known, to have preceded all the reft. 

 They were neither of them, even at that time, entirely new pro- 

 pofitions, though, in the conduct of the inveftigation, and in the 

 ufe made of them, a great deal of originality was difplayed. 

 The comparifon of them naturally fuggefted to a mind not 

 fettered by prejudice, nor fwayed by authority, that they are 

 two fteps of the fame progrefTion ; and that, as the prefent con- 

 tinents are compofed from the wafte of more ancient land, fo, 

 from the deftruction of them, future continents may be deftined 

 to arife. Dr Hutton accordingly, in the notes to which I al- 

 lude, infifts much on the perfect agreement of the ftructure of 

 the beds of grit or fandftone, with that of the banks of uncon- 

 folidated fand now formed on our fhores, and fhews that thefe 

 bodies differ from one another in nothing but their compact- 

 nefs and induration. 



In generalizing thefe appearances, he proceeded a ftep farther, 

 confidering this fuccefhon of continents as not confined to one 

 or two examples, but as indefinitely extended, and the confe- 

 quence of laws perpetually acting. Thus he arrived at the new 

 and fublime conclufion, which reprefents nature as having pro- 

 vided for a conftant fucceffion of land on the furface of the earth, 



according 



