THEORY OF THE EARTH 27 



violence is diminished, or when they arrive at 

 more expanded basins, where their waters are 

 permitted to spread, they throw out upon their 

 hanks the largest of those stones which they had 

 rolled down. The smaller fragments are deposit- 

 ed still lower ; and nothing reaches the great 

 canal of the river excepting the minutest par- 

 ticles, or the most impalpable mud. It often 

 happens, also, that before these streams unite to 

 form great rivers, they have to pass through large 

 and deep lakes, in which their mud is deposited, 

 and from which their waters come forth limpid. 



The lower rivers, and all the streams which 

 descend from the less elevated mountains and hills, 

 also produce effects, upon the districts through 

 which they flow, more or less analogous to those 

 of the torrents from the higher mountains. When 

 these rivers are swollen by great rains, they attack 

 the base of the earthy or sandy hills which they 

 meet with in their course, and carry their fragments 

 to be deposited upon the lower grounds, and which 

 are thus, in some degree, raised by each succeed- 

 ing inundation. Finally, when the rivers reach 

 great lakes or the sea, and when that rapidity, 

 which carried off and kept in suspension the par- 

 ticles of mud comes to cease entirely, these parti- 

 cles are deposited at the sides of their mouths, 

 where they form low grounds, by which the shores 

 are prolonged. And if these shores are such, that 



