INTRODUCTION. 33 



racter to its channel. If deep and slow, whatever 

 particles of earth it contains are deposited in the 

 consistence of mud. If shallow and rapid, the 

 lighter earthy matter is washed away, and the 

 bottom is covered with stones, v/hich become 

 boldered by their action on each other. So the 

 surface of the earth is now found to be sand, 

 gravel, loam, clay, or bare rock, according to the 

 depth or rapidity of the currents which passed, 

 and in passing deposited them. 



Although the general surface was formed by 

 the action of the deluge, there has been formed, 

 since, other descriptions of soil, which are parti- 

 cularly useful in the cultivation of flowers, and 

 which will be noticed in their place. 



Sand, — This is composed of stones of the 

 smallest dimensions, equal in size and figure, 

 semi-transparent, and light enough to be carried 

 along by action of water, which washes it clean 

 from other earthy matter, and deposits it in 

 beds below the shelves of the channel. It is a 

 residuum from lighter earths, or the detritus 

 of rock or gravel, separated by a lively current, 



D 



