DILUVIAL OR GLACIAL SOILS. 233 



ranked the pmty soils, which consist mostly of vegetable 

 matter, partly decayed and partly in a state of preservation. 

 This variety of soil is of every degree of texture and fertility. 

 Some of the peat meadows and swamps contain pure peat, 

 with a small quantity of mineral matter. In this case, 

 they should be regarded rather as depositories of fuel and ma- 

 nure. But they can be made the most valuable of all soils, 

 because they contain inexhaustible quantities of vegetable 

 food. 



Peaty soils, include all those in which are found large 

 quantities of vegetable matter, in a partially decomposed state. 

 A large portion of the peaty soils are left wholly barren, 

 through want of chemical skill to bring them into the proper 

 state for producing crops. 



11. Diluvial or glacial soils.* These are more extensive 

 than any other. They seem to have resulted from the action 

 of glaciers, when the position of the earth was different from 

 what it is at present. They are composed of sand, gravel 

 and rounded pebbles, which are mingled together and appear 

 to have been moved, in a southerly direction from the rock 

 out of which they were formed. In consequence of this trans- 

 portation of the abraded materials, by glacial or some other 

 action, the detritus of several kinds of rock are in some cases 

 commingled. In others, the materials are not carried far be- 

 yond the rock from which they were formed ; so that the ex- 

 tent of this division of soils is much less, than would other- 

 wise appear. 



Diluvial soils may be divided into three varieties ; sandy, 

 gravelly and argillaceous. 



1. The sandy and gravelly diluvial soils differ only in the 

 relative fineness of their materials. The most common varie- 

 ties consist of course sand, and rounded pebbles. These are 



" Called glacial soils because it is now pretty well established, that 

 the diluvial or drift was formed by glaciers. (See Hitchcock's Report 

 of the Geology of Massachusetts.) 



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