CONTENTS. 



Page. 



General statement 5 



Lag gravels 7 



Driftlng sand 9 



Rolled drifting sand 11 



Dune sand 12 



From New Boston, 111 13 



" Michigan City, Ind 14 



" Cordova, 111 15 



" Bice county, Kans 16 



" Folly'sCove, Mass 16 



" North Dakota 17 



•' Green River Basin, 111 17 



" Lindsborg, Kans IS 



" Nebraska 18 



" Moline, 111 20 



" Henderson county. 111 20 



General remarks on dune sand 22 



Comparison with incipient drifting 26 



Lee sand .-. 27 



General observations 27 



Sand from Rice county, Kans 28 



Sand from Moline, 111 29 



Sand from North Dakota 29 



Sand from Lindsborg, Kans ;!0 



Inferences 31 



Atmospheric dust 31 



Materials carried under unusually favorable conditions 31 



Dust collected in railroad coaches 32 



Volcanic dust 33 



Dust near wagon roads 38 



Inferences 39 



Ordinary atmospheric dust 39 



Dust collected directly from the atmosphere 40 



By means of broom-corn whisks 40 



By means of muslin 43 



By means of a hollow cylinder 44 



Dust taken on natural surfaces above the ground 47 



Shower dust 51 



Average composition of atmospheric dust 58 



General conclusions 60 



Summary 64 



The problem of the loess 67 



