DUIFTING HAND. 



17 



Some sand has been collected from small and freshly 

 formed drifts on plowed fields and on the open prairie in 

 the eastern part of North Dakota. Two samples of this 

 have been placed arbitrarily with the rolling sand, but 

 these differ only slightly from those given here. The rather 

 large amount of dust in all of these analyses is evidently 

 due to the fact that the wind has just begun its work on 



Table VII. Mechanical Composition of Dune Sand from Folly's Cove, Mass. 





35 



36 





Length or 



diameter in 

 mm. 



Dune sand. 



Dune sand. 



Average. 



16-8 









8-4 









4-2 









2—1 





.1 



tr. • 



1-i 



6.8 1 



4.3 1 



5.5 1 



\—h 



27.8 h 



19.0 1 



23.4 1 



i-i 



6-3.8 HI 



71.4 ^m 



67.6 k 



1 1 



.7™ 



4.0 



2.4 P 



1 1 

 TTT 3^ 







.1 



tr. . 



1 1 









64 128 









143 S56 











surface deposits, which contain line materials in some 

 abundance (Tab. Vlll). 



Scattered dunes occur in the basin of the Green river 

 in Illinois. Though the superficial deposits here are but 

 little affected by the action of the atmosphere now, the 

 topography of several sandy belts in this valley indicates 

 earlier deflation by the atmosphei'e. The sand is moder- 

 ately well sorted (Tab. IX). 



