9 8 ELEMENTARY SCIENCE 



upon this strictly eolian soil, as along the east coast of 

 Lake Michigan. The "sand-hill region" of western Ne- 

 braska is a great tract which is practically useless for 

 agriculture because of the strong winds which blow the 

 loose sand about. 



Eolian soil that contains more of dust than of sand is 

 called loess (pron. lus). Soil which is partly sand and 



FIG. 43. Sand-dunes. 



partly clay (and usually partly humus) is called loam. So 

 we see that loess is eolian loam. Some of the richest agri- 

 cultural regions are regions of loess. There is much of loess 

 in the Mississippi and Missouri river-basins. Loess for- 

 mations in China are famous for their depth, and many of 

 those in Europe for their fertility. 



Ice was (and to some extent is to-day) a third great 

 factor in the transportation of soil. You have read of the 

 glaciers and of the great effects they produced, especially 

 in northeastern and north-central United States (see 

 chapter VIII). You know that the material deposited by 



