[369] SCIENTIFIC MANUAL. 83 



the folly of a wholesale destruction of forests. It is a well 

 known fact that the destruction of forests causes the grad- 

 ual drying of the climate. 



CHAPTER VI. 

 SOILS IN THEIR RELATION TO VEGETATION. 



Soils naturally depend for their mineral elements upon 

 the source from which they are themselves derived, but 

 their fertility often depends more upon artificial treatment 

 than original source. 



All soils owe their origin primarily to rocks, and are 

 ameliorated by vegetation, the larger part of the latter 

 having been derived from the atmosphere. 



Soils, as regards their origin, are classed as sedentary and 

 transported. 



Sedentary soils are those which overlie the rocks from 

 which they have been formed. A very correct idea of 

 their original mineral constituents may be obtained from 

 those of the underlying rocks, allowing of course for modi- 

 fications resulting from the process of decomposition, and 

 subsequent treatment. Such soils are found in Middle 

 and North Georgia. 



Transported soils are such as have been drifted from the 

 locality of the parent rocks, and deposited by the agency 

 of glaciers or floods, in regions less elevated than those in 

 which they originated. 



Transported soils are subdivided into drift, alluvial and 

 colluvial, according to the circumstances of their deposi- 

 tion. 



Drift, is found on the border of the primary and 

 tertiary formations of this State, extending from Augusta 

 across to Columbus, and may be distinguished by the pres- 

 ence of rounded, water-worn pebbles and boulders, im- 

 bedded in the soil. 



