54 



SOILS. 



the limestone is about eight feet, but ranges from seven to ten ; 

 the upper layers of the limestone are somewhat softened, but 

 the rock is always fresh at twelve feet, from which depth the 

 sample analyzed was taken, in a cistern adjoining the field from 

 which the soil and subsoil were procured. The black soil 

 varies in depth from 8 to 15 inches; then there is a change to 

 a brownish subsoil, reaching down to about two feet, and in 

 drying cleaving into prismatic fragments. The black soil has 

 here in the highest degree the peculiarity of crumbling in dry- 

 ing from its water-soaked condition, so that it may be plowed 

 when wet without injury, although in the roads it works up 

 into the toughest kind of mud. The prairie is sparsely tim- 

 bered with compact, fair-sized black-jack oak, accompanied 

 originally by red cedar. 



The limestone derives its popular name of " rotten " from 

 its being usually soft enough to be cut with a knife or hatchet, 

 and is therefore somewhat used for building, and for burning 

 lime. 



COMPOSITION OF LIMESTONE, AND RESIDUAL SOIL AND SUB-SOIL, FROM BLACK 

 PRAIRIE, MONROE CO., MISSISSIPPI. 



