DRtFTMNG SAND; 



]'.) 



North Dakota. 



Average. 



Tabh IX. Mechanical Composition of Drifting 

 River Valley, Ills. 



Sand from Green 





43 



43 





Length ot 



diameter In 



mm. 



Dune sand 

 from Tampico. 



Dune sand 

 from Hooppole. 



Average. 



tr. I 



examined, nor do these contain 

 more than a trifle of dust. It may 

 be said to be the most uniformly 

 sorted of all the sands described 

 (Tab. XI). Two of the samples 

 (nos. 47 and 48) were selected to 

 represent the extremes of varia- 

 tion among a series of layers 

 which were seen in an exposure 

 with well defined bedding-. One 

 was taken from the coarsest seam 

 which could be seen and the other 

 from the finest. The difference 

 in texture was quite apparent to 

 the eye, as the seams appeared 



Table X. Mechanical Composi- 

 tion of Drifting Sand from Linds- 

 borg, Kans. 





44 



LeDgth of 



diameter in 



mm. 



Drifting sand. 



16—8 





8-4 





4—2 





2—1 





1-4 



3.1 ( 



i-i 



23.3 1 



i-j 



Go.i h 



i-iV 



3.9 



iV-3'2 



.4 



1" 1 



'Si 4 





04 128 





li"^ TST 





