THE ELEMENTS OF SOILS. 6 1 



CHAPTER V. 



THE ELEMENTS OF SOILS. 



xm. THE ELEMENTS. We have observed that 

 the soils are composed of organic and inorganic ma- 

 terials. Our experiments have shown us that the 

 larger part of every farm or garden soil fit for useful 

 plants is composed of rocks in the form of sands and 

 clays. Naturally we might wonder if the different 

 rocks do not make different soils. Is not the soil 

 made from the granite hills of Eastern Massachusetts 

 very different from the soil formed from red sandstone 

 in New Jersey, or the yellow drifting mud of the Mis- 

 sissippi? This is quite true. These soils are different, 

 but the differences are not so great as between a soil 

 with much sand and one with much clay. Besides 

 this, we have observed that the rocks have been weath- 

 ered and made into sandstone and shales, and these 

 again into sand and clay, so many times, that soils as 

 we find them to-day contain every kind of rock. The 

 changes in the surface of the earth have been so great ; 

 the upheavals of mountains, the action of floods and 

 ice, earthquakes, and the slow denudation of hills, have 

 been continued so long, that the stony remains of 

 old rocks are mixed together in hopeless confusion; 



