CHAPTER IV. 



PHYSICAL CLASSIFICATION OF SOILS. 



classification of soils into Sedentary (or Indigenous) 

 and Transported has been already mentioned. Transported 

 soils are again subdivided into Diluvial and Alluvial. Dilu- 

 vial or Drift soil consists of soil proper mixed up with stones 

 and boulders. These are usually formed from various kinds 

 of rocks. Alluvial soil consists of fragments or particles of 

 minerals arranged according to their size and also partly 

 according to their specific gravity. Alluvial soils are, as a 

 rule, more fertile containing fragments of rocks of different 

 geological periods. Alluvial soils mixed with more or less 

 angular fragments of rocks on which they lie are called 

 Colluvial. 



45. Soils are also classed as Light and Heavy, Warm and 

 Cold, Moist and Dry. They are also classified according to the 

 crops which do best on them, or which ought to be grown on 

 them for economical reasons. Richest soils are called garden 

 soils ; middling clay loam soils, wheat soils ; hard clay which 

 is expensive to work, pasture soil ; poor harsh land, wood 

 soil. Soils are also classified according to their prevailing 

 physical constituents. These are, stone, gravel grit, sand, 

 clay, calcium carbonate, vegetable matter and moisture. 

 Soils are thus divided into stony, gravelly, gritty, sandy, 

 clayey, calcareous, peaty and marshy. There is however no 

 hard and fast distinction between one group and the next. 



