308 MAN'S USE AND CONSERVATION OF SOILS 



upon the surface of the bed rock, which may contain few, 

 if any, of the constituents which were in the soil. This 



soil, which in no way 

 resembles the under- 

 lying rock, is called 

 transported soil. We 

 have already learned 

 how most of it reached 

 its present position. 



The first kind of 

 soil has evidently been 

 formed in some way 

 from the rock below, 

 since it gradually 

 shades into this rock. 

 This kind of soil 

 changes with the 

 change of the bed 

 rock. A striking il- 

 lustration occurs in 

 Kentucky, where the 

 rich and fertile "Blue 

 Grass " region is 

 bounded by the poor 

 and sandy " Barrens." 

 The one is underlaid 

 by limestone and the 

 other by sandstone. 

 The soil at the surface is usually finer than the soil a 

 foot or so below the surface. Sometimes it has a great 

 deal of decayed vegetable matter mixed with the decom- 

 posed rock and to this its fertility is often largely due. Some 



LOCAL SOIL 



This soil has been weathered from the under- 

 lying rock. 



