TRANSPORTATION OF SOILS 201 



144. TRANSPORTATION OF SOILS 



If we examine the surface soil and the lower layers of soil, 

 we are liable to find that they are entirely different. This 

 indicates that the soils have been brought from some other 

 place and deposited. Soils do not always stay where they are 

 formed. 



The factors which enter into transportation of soils are 

 wind, water, and earthworms, together with other lower 

 organisms. Rivers carry an immense amount of soil-making 

 material, and often deposit it, thus changing the river's 

 course. This alluvial soil is one of the richest which we have. 

 Rain wears away hills and mountains and supplies the rivers 

 with their burden of soil. In colder climates, as we have 

 learned, the frosts break up the soil and loosen it, preparing 

 it to be washed away by the rain. In larger masses of ice, 

 namely, glaciers ; enormous transportation of rock and soil 

 takes place. We can see this where there have been glaciers 

 in prehistoric times, and can realize, on account of the actual 

 mountains of material which they have left, that their load 

 must have been tremendous. Winds also move the soil of 



