199 



A general discussion of the glacial geology and studies of the ecological 

 and zoological relations of these areas will be found in a bulletin by 

 Messrs. Hart and Gleason.* 



These areas are characterized by a rather coarse sand which con- 

 tains but little plant food and is being constantly shifted by the wind. 

 In places it forms low hills and dunes above the flat plain of the bot- 

 toms. In some localities the sand has encroached on the upland, 

 forming dunes on the edge of the original clay blufifs. In others it 

 forms extensive level Or gently undulating plains. It is everywhere 

 characterized by wind forms such as "blowouts" and traveling dunes. 

 Parts of it have no vegetation, and a great deal is covered with various 

 grasses. The forest typical of this soil has a very light crown cover, 

 and consists of small short trees of a generally scrubby appearance. 



This sand-dune forest type varies in the mixture of species. Along 

 the Mississippi it consists largely of black oak, with some hickory 

 and blackjack. On the Illinois bottoms it seems to run more to 

 blackjack oak, with less black oak and hickory. 



The trees are small, short-boled, and where they have been cut 

 over or badly burned, the resulting sprouts form a dense stand of 

 "brush." In some places black oak reaches fair size and would be 

 merchantable for ties. Most of the growth, however, is suitable only 

 for cordwood, and is seldom more than six inches in diameter, 

 breasthigh. 



The land is generally pastured and is frequently burned in an 

 endeavor to hasten the spread of the scanty grass cover. Because of 

 the dry top-soil, fires start easily and are very harmful. Much of the 

 land has been clear cut for firewood, and is now covered with an 

 even-aged stand of sprouts, six to ten vigorous shoots to every stump. 



This should be considered absolute forest land, since the attempts 

 at agriculture have been generally unsuccessful and the constantly 

 shifting sand menaces the fertile bottoms near by. Some fields have 

 four to six inches of sand blown over them in the course of one 

 winter; and passage over any of these plains on a windy day subjects 

 a person to a veritable rain of sand. If this land were kept under a 

 permanent forest cover, the shifting of sands would stop and the soil 

 eventually become fertile. But it would have to be managed for 

 wood crops exclusively and protected from fire and grazing. At first 

 some planting would be necessary. 



*Biill. 111. State Lab. Nat. Hist., Vol. VII, Article VII. Urbana, 111., Jan., 

 1907. 



