ON CERTAIN ASPECTS OF THE LOESS^ OF SOUTH- 

 WESTERN IOWA. 



Recently the Chicago, Burhngton & Quincy Railroad has made 

 some extensive cuttings on a new right of way in southwestern Iowa, 

 affording thereby excellent opportunities for observations on the loess 

 and the underlying till. These cuts are especially interesting on 

 account of the varied aspects presented by the surface material over- 

 lying the glacial drift. Three sheets of loess in the same vertical 

 section are discernible. 



First, or uppermost, is the ordinary yellow deposit of the Missouri 

 bluffs phase common at the surface everywhere throughout the region, 

 and which needs no further description . 



Underlying this loess is a loess of different character; it is whitish 

 in color, and is more clay-like in texture than the ordinary deposit. 

 It appears also to contain less calcareous matter. The white loess 

 and the yellow loess are distinguishable, not merely in fresh section 

 by their difference in color and texture, but also in weathered expos- 

 ures by their different- aspects. The yellow loess tends to assume 

 that peculiar facies familiar to all who have seen the western phase of 

 the loess, whereas the white loess displays more of the behavior of a 

 joint clay, especially as regards superficial drying and cracking. 



Below the white loess and in marked contrast with it in the matter 

 of color is a red loess. This red loess occasionally contains a few 

 calcareous nodules of the general appearance of loess kindchen ; its 

 lowermost six inches contain pebbles of various sorts, but these rarely 

 exceed the size of a bean and are absent from the upper part of the 

 deposit, as they also are from the white and the yellow loess. In 

 texture the red loess resembles somewhat the white loess above it; 

 it is apparently a little less clayey. 



I It may not be out of place to remark that there seems to be a tendency to give 

 the word "loess" a specific meaning rather than to assign to it a generic significance, 

 which would be more desirable. To the writer loess means any considerable accumu- 

 lation of surface material, eolian in origin, the component particles of which are too 

 small to give the deposit the character of sand or grit. Subject to this limitation, 

 loess may have any texture or any color, as well as any peculiarity of topographic 

 facies. 



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