47 



with lime and organic matter being intimate, and in such 

 proportions, that no one has any striking predominance 

 over the other. 



Practice has introduced also a further distinction of 

 pasture or grass lands, which constitute the bulk of all our 

 mountains, and soils not adapted for husbandry, and arable 

 land ; the latter comprising all varieties of soil under 

 tillage. 



II. OF VARIETIES IN THE CLASSES OF SOILS. 



The classification of soils, according to their constituent 

 elements, will require in practice some subdivision, as 

 each class of soils contains several varieties, and great 

 diversity in value. 



1. Siliceous soils may be divided into 1, loamy; 2, 

 sandy ; 3, gravelly ; 4, slaty ; 5, stony. 



2. Argillaceous soils may be divided into 1. alluvial; 



2, friable clay ; 3, stiff clay. 



3. Calcareous soils may be divided into 1, loamy; 2, 

 marly; 3, gravelly; 4, stony. 



4. Peaty soils may be divided into 1, bog-land; 2, 

 moor ; 3, bog. 



III. OF SILICEOUS SOILS. 



It has been already observed, that silica is the most 

 abundant element in the composition of soils. The disin- 

 tegration of all rocks will furnish the elements of a siliceous 

 soil, but some rocks yield richer sands than others. Lime- 

 stone, freestone, and the trappean rocks generally afford 

 materials for the most luxuriant soils. Granite, mica slate, 

 and clay slate are usually inferior to the former. 



The varieties of siliceous soils are 1, loamy; 2, sandy; 



3, gravelly ; 4, slaty ; 5, stony. 



1. Siliceous loams. These are among the most fertile of 

 all known soils. It is a characteristic of loams to have 

 the materials of which they are composed so nicely ad- 

 justed, that the predominance of any one part over the 

 others is not so strongly marked as in inferior soils. They 



