

"'%i^ 





m 



■eis 



PtrL 



\ 



\ 



'•«> 



in 



'Mt 



t&; 



ii 



'%^ 



^hl 



■^^oneafj 



» i' * 





Pr 



!^ 



-tct 



Iv 



4 



«4U 



i^ 



^'■^^ i 



» 



are 



''^-, 



..::'-^^W 



•ih 



' " * n. 



T' 



■ ktk 



I f 



1 



: :)ii{)crioiE; 



'i; 



; apparec!, 

 ihe roch jf! 



r I 



t 



f}ion![h. 



I 



I 



■ CiijiiiJ'""""' 



1 



•yn 



ie Isr ii- 



-.♦lie 

 river?, 



t-:. 



0^' 





■0' 



ij. 



J-' 



HUTTONIAN THEORY 



\ 



361 



322. In order to give uniform declivities to 

 the rivers, the lakes muft not only be filled up or 

 drained, but the catarad, v*'herever there is one, 

 ipuft be .worn away. The latter is an operation 



fes vifibl 



1 



e 



ft 



as it pre 



3 itfelf over the rocks, hurries along with ii 

 only fand and gravel, but occaiionally larg 



^ 



ftones 



h grind and wear d 



the rock 



with a force proportioned to their magnitude 

 and acceleration. The fmooth furface of the 

 rocl^s in all w^aterfalls, their rounded furface, 

 and curious excavations, are the moft fatisfac- 

 tory proofs of the conftant attrition which they 



ocks are deeply in- 

 m reach to a great 



du 



d 



h 



th 



feded, thefe 



ks 



ft 



ght above the level on which th 



fl 



The ph 



m 



fucli in ft 



a 



ong the arguments beft calculated to remove 



all 



edulity refpeding the wafte which 



vers have produced 



d 



are 



produc( 

 that th 



contmuing 



n- 

 to 



are 



rad 



They fuffer no doubt to remain, 

 height and afperity of every waterfall 

 nually diminifliing; that innumerable 

 are entirely obliterated ; that thofe 



which remain are verging toward the fame end, 

 and that the Falls of Montmorenci and Niagara 

 itiuft ultimately difappear. 



323. Though there can be no doubt of the juft- 

 ^lefs of the preceding concluftons, when applied 



to 



I 





