70 SOILS AND FERTILIZERS 



their onslaught," l have covered desolate and rug- 

 ged rocky wastes with rich soil. These two active 

 agencies in the formation and transportation of soils 

 - streams and glaciers produce soils varying in 

 character and hence in name, diluvial soil is due to the 

 action of streams, and drift soil is a result of glacial 

 action. 



Alluvial Soils. --These soils will naturally be formed 

 of layers, or strata, because the moving water, carrying 

 as it does both coarse and fine particles, will deposit 

 both, the heavier, coarser particles being deposited first. 

 Successive years will repeat this process, hence a soil 

 will be formed of alternate strata of coarse and fine 

 soil, varying in depth, being more shallow in the source 

 regions of the stream and gradually increasing in depth 

 towards the mouths. Such soils are commonly fertile, 

 being made up principally of the finest particles of soil 

 of the basin because they are moved the most easily by 

 the running water. The surface of these soils is nat- 

 urally smooth and level. 



Drift Soils. Drift soils are made up of stones with 

 a greater or less amount of fine material. There arc 

 few strata in these soils, but the depth varies as greatly 

 as does that of alluvial soils. Because of the varying 

 nature of the surface over which the glacier has moved, 

 the surface of the drift soil formed is hilly and usually 

 contains many stones. 



If the glacier has moved over and ground up 

 limestone in its progress, the drift soil made is com- 

 monly productive, but if the main rock ground up has 

 been sandstone, there is little fertility in the resulting 

 soil. 



1 Stockbridge. 



