32 



THE PRINCIPLES OF SOIL MANAGEMENT 



Table II. Complete Chemical Composition of Rocks 

 and Residual Soils. 



In addition to these large areas, many small areas occur 

 scattered through areas of other kinds of soil. 



The most nearly original soil is that formed from 

 igneous rocks. That is to say, the composition of such 

 a soil might be expected to approach most nearly to 

 that of the original rock. The relative composition of 

 several igneous rocks and the soils derived from them, 



