2i8 ILLUSTRATIONS OF THE 



nature ; fo that they bat retard for a while the 

 progrefs by which they are all refolved into duft, 

 and fooner or later committed to the bofom of 

 the deep. 



117. We are not, however, to imagine, that 

 there is no where any means of repairing this 

 wafte J for, on comparing the conclufion at 

 which we are now arrived, viz. that the prefent 

 continents are all going to decay, and their ma- 

 terials d^^'.fcending into the ocean, with the pro- 

 pofition firft laid dov/n, that thefe fame conti. 

 nents are compofed of materials which rauft have 

 been colleded from the decay of former rocks, 

 it is impoffible not to recognife two corre- 

 fponding fleps of the fame progrefs ; of a pro- 

 grefs, by which mineral fubdances are fubjeded 

 to the fame feries of changes, and alternately 

 wafted away and renovated. In the fame man- 

 ner, as the prefent mineral fubftances derive 

 their origin from fubftances fimilar to them- 

 felves ; fo, from the land now going to decay, 

 the fand and gravel forming on the fea-ftiore, or 

 in the beds of rivers ; from the ftiells and corals 

 which in fuch enormous quantities are every day 

 accumulated in the bofom of the fea ; from 

 the drift v/ood, and the multitude of vegetable 

 and animal remains continually depofited in the 

 ocean : from all thefe we cannot doubt, that 

 ftrata are now forming in thofe regions, to 



which 



( 



