338 



ELIOT BLACKW ELDER 



life zones, and the sagebrush and aspen slopes of his Transition zone, 

 are apparently, however, the sites of considerable eolian deposition. 

 For example, along the grassy and forested western slope of the 

 Teton Range, a thick structureless soil mantles the surface. Occa- 

 sional exposures show that it is from two to twenty feet deep, 

 entirely free from sand, gravel, or bowlders, and of a yellowish or 

 buff color. The chemical analysis given in Table III shows that 

 it is similar in composition to the loess of the Mississippi and 

 Missouri valleys. 



TABLE III 

 Table of Analyses of Loess* 



Teton Mountains, 

 Wyoming 



Iowa 



Missouri 



SiOj 



Al A 



FeA 



FeO 



TiOa 



PA 



MnO 



CaO 



MgO 



Na^O 



K.O 



H.0 



CO. 



SO3 



C, organic . . . . 

 Undetermined . 



72.04 



i2.37t 



3-38 



0.37 



1. 21 

 1. 22 

 1.83 

 2.58 



3-15 

 trace 



72.68 

 12.03 



3-53 

 0.96 

 o. 72 

 0.23 

 0.06 



1-59 

 I. II 

 1.68 

 2.13 



2.5ot 



0.39 

 0.51 



0.09 



74.46 



12. 26 



3-25 

 0.12 

 0.14 

 0.09 

 0.02 

 1.69 

 1. 12 

 1-43 

 1.83 

 2.70 

 0.49 

 0.06 

 0.12 



1. 8s 



99.78 



* Analyses 2 and 3 are taken from a paper on "The Driftless Area" by T. C. Chamberlin and R. D. 

 Salisbury, 6th Ann. Kept., U.S. Geol. Survey, i88s, p. 282. 

 t Including TiOa, PuOs, MnO, etc. 

 J Contains H of organic matter. Dried at 100° C. 



1. Loess overlying old drift, one mile east of Alta, Teton Creek, Teton Mountains, Wyoming. 

 Sample taken two feet below the surface. Analyst, W. C. Wheeler, U.S. Geol. Survey, 1912. 



2. Loess near Dubuque, Iowa. 



3. Loess from river bluflf at Kansas City, Missouri. 



It is suggested that this widespread veneer of loess consists 

 largely of the dust blown by the westerly winds from the dry 

 regions of Oregon and Idaho and strained out by the vegetation on 

 the mountain slopes. It is significant that such deposits are not 

 characteristic of the Wind River and Green River basins, which 



