90 THE CHEMISTRY OF CREATION. 



of animals have passed away from the face of 

 the earth, and that, during this whole period, 

 night and day, these stones have gone rattling 

 onwards in their course, I have thought to 

 myself, Can any mountains, any continent, with- 

 stand such waste ?" 



The material washed down by rivers after it 

 has been disintegrated by chemical forces, and 

 deposited under water either in the sea or in a 

 lake, is called alluvium, when in the course of 

 natural events it is at length raised above the 

 surface of the water, as when, by some circum- 

 stance, the course of the river becomes altered, 

 and the matter it formerly carried towards the 

 sea becomes exposed. It constitutes, in fact, 

 what may be called the mineral soil of many 

 valleys, such as that we are contemplating, 

 lying just underneath the vegetable soil formed 

 chiefly by the decay of vegetable matters. It 

 consists of sand, gravel, stones, and fine sedi- 

 ment or mud, most of which may be often 

 traced back -to their source in the mountains or 

 hills in which the rivers took origin, simply by 

 analyzing them, and finding out their respec- 

 tive composition. We may thus, frequently, 

 with some certainty, on taking up a stone from 

 the bed of the torrent, and examining it at 

 home, were we to find it composed of lime, 

 declare that it was broken off and carried from 



