20 



DKlFTING SAXt). 



in the natural exposure, but it seems rather insignificant 

 in the analyses. 



South of the city of Moliue in Illinois there are some 

 drifts of sand in a remnant of an old terrace. It rises like 

 an island in the bottom lands of Eock river. The bulk of 

 the assorted material in this elevated land is quite fi-ee 

 from coai"se ingredients 1 uit there is a considerable admis- 



Tahle XI. Mechanical Composition of Dune Sand from Western Nebraska. 





45 1 46 [ 47 j 48 





Leneth 

 of diameter 



In mm. 



Done sand, ' Front 8loi>e of 

 Alliance. done, Alliance. 



Coarse seam 



in done nand, 



Hyannls. 



Fine seam 



In dnnesand, 



Hyannifi, 



Average. 



16-8 

 8-^ 















2-1 

 1-i 



1 1 



4 S 



1V-3V 



70.5 pi 



"1.1 1 



i(;.2 g 

 80.3 ■I 

 1.9 \ 



2.8 1 



IU.2I 

 71.3 PH 

 1:3.8 1 



1.9 



0.6 



;:::r 



IL 



0.9 1 



tr. 



W-tV 













64 128 













TSS »56 











ture of fine fragments. Some of these are yet retained, it 

 seems, in the drifting sand,, which has not been carried 

 farther than two or three hundred yards (Tab. XII ). 



In the southern part of Henderson county in Illinois 

 there is a range of sand hills which follow the bluffs of the 

 ^lississippi river. In their topogTaphic features these 

 hills resemble sand dunes, but the activity of the winds 

 seems to have come to a standstill at present, except in a 



