SOILS OF ILLINOIS. 

 Table of soils of Illinois — Continued. 



791 



Variety. 



Sandy. 



Origin or mode of deposition. 



Glacial drainage, 

 streams, lakes, winds. 



Aronl distribution. 



Mainly in basins aloug the Kankakee, Green, and 

 lower Illinois rivers; old lake bottom and raised 

 beaches near Chicago; also or. bottom lands, 

 and fringing in many places the low bluffs of 

 streams, and locally developed on areas of gla- 

 cial formations. 



Silts pervious to water ' In part by slowly llow- 

 (chiefly the typical iug waters ; probably 

 in part by wind. 



Along the Mississippi, lower Illinois, lower Wa- 

 bash, and lower Ohio rivers; also between the 

 Illinois and the Mississippi from the Green River 

 Basin south to the latitude of Peoria, and in the 

 basin of the Big Bureau Creek, in Bureau 

 County. 



Silts slowly pervious to In part by slowly flow- 

 water, ing waters ; probably 

 iu part by wind. 



Silts nearly impervions Nearly still waters; per- 

 to water. (Two kinds, haps wind in part, 

 namely, white clays 

 and gumbo ) 



Peaty and marly. 



Vegetal accumulations 

 and shell deposits. 



Mainly in west-central Illinois, west of a lino con- 

 necting Alton, Litchfield, Pana, Decatur, and 

 Peoria; also on the eastern border of the Mis- 

 sissippi Valley loess belt, in the northern part 

 of the State. 



White clays cover much of southern Illinois south 

 of the Shelbyville moraine, as far west as the 

 Mississippi loess, east to the W abash loess and 

 south to the Ohio River loess. Gumbo is found 

 on some bottom lands along the main rivers. 



Locally over the greater part of the State wher- 

 ever drainage is imperfect. Peat is rare south 

 of the latitude of Springfield, but it abounds in 

 the northeastern quarter of the State, in hogs. 

 Marl deposits are less extensive than peat, but 

 are fully as widespread. 



RESIDUARY SOILS. 



The residuary soils show variatious which correspond in a rude way 

 with variations in the structure of the rocks from which they are derived, 

 there being in regions underlain by shale or limestone a more compact and 

 adhesive soil than in sandstone regions. Each class of limestone has its 

 own peculiar soil, and soils derived from shales range from stiff clay to a 

 sandv material. A complete analysis of the nature of the differences dis- 

 played by the several classes of residuary soils has not been made. With 

 proper rotation of crops these soils are usually fertile, but otherwise they 

 become exhausted sooner than soils formed on glacial drift. 



