30 



A large proportion of the area has been forested, and most of 

 that part is not under cuUivation. Some fields have been cleared and 

 abandoned, and are now densely covered with a thick growth of 

 small trees. The portion originally covered with prairie is almost 

 entirely under cultivation. Some large areas of blowsand occur, 

 caused in many cases by pasturing or plowing'. A conspicuous in- 

 stance may be seen just south of Keithsl^urg, where the railroad 

 passes through a blowout complex, with one large tra\eling dune. 



T]ic Kankakee Area. — This is undoubLedly the largest sand area 

 re]iresented in the state, but at least three fourths of its total extent 

 lies in Indiana. Leverett {i8gg: 328-338) has given a detailed ac- 

 count of its extent and thickness, and from him the following state- 

 ments are taken. The sand occupies a roughly semiciicular area, 

 with the curved edge to the south. Beginning in western Marshall 

 county, Indiana, the sand margin curves to the south and southwest 

 near the Tippecanoe river, passes westward near the towns of Monti- 

 cello and Kentland into Iroquois county, Illinois, and thence follows 

 the Iroquois river north to the Kankakee river, which forms the 

 northern boundaiy of the area. This area includes about 3000 

 square miles (7500 sq. km.). The deepest deposits lie near the Kan- 

 kakee river, ^^■here the sand extends ".several feet below the level of 

 the base of the ridges." 



As in other areas the sand is not necessarily continuous. Es- 

 pecially near the Ijorder of the area it is heaped into irreg"ular ridges 

 and dunes, ])r()]Kil)ly caused by wind, and l:;etween them lie areas of 

 sandy loam or muck. As in the .\mboy area, the appearance indi- 

 cates a slow recession of water, with the last of the hydrophytic 

 vegetation still persisting. While the presence of the sand is cer- 

 tainly due to glacial outwash, Leverett does not give more definite 

 conclusions. 



At the present time all the upland sand ridges are either forested 

 or under cultivation, while the lowlands of peat, nuick, or loam are 

 occupied by swamp or meadow associations. Brief notes on the vege- 

 tation, with maps showing the distribution of the sand in Newton and 

 Marshall counties, Indiana, have been published Iw the Bureau of 

 Soils (Neill and Tharp, igo"/', Bennett and Ely, /Q05). But little 

 attention has l)een given to this area during the present investigation. 



The JVinnehago Area. — This series of sand deposits lies chiefly 

 in the northern part of Winnebago county, Illinois, and the southern 

 part of Rock county, Wisconsin. It has been mapped "and described 

 bv the Soil Survey (Bonsteel, iQO^h\ CofTey, Ely, and Mann, IQ04). 

 The sand lies between the valleys of Sugar river and Rock river, in 



