A PHENOMENON OF THE KANSAN DRIFT IN NEBRASKA 



ERWIN H. BARBOUR 



University of Nebraska 



Among the minor phenomena of the glacial drift in Nebraska 

 there is one which, though rarely observed by the pubhc, is of 

 interest and should be commended to the attention of naturalists. 

 The reference here is to certain large, well-defined masses or blocks 

 of such materials as sand, gravel, and coarse pebbles, which occur 

 imbedded in the drift clays along with glacial bowlders, and which 

 presumably have been similarly transported and deposited. These 

 masses or blocks vary widely in color, texture, and kind. They 

 also vary from the glacial matrix in which they are found and are 

 the more striking by virtue of contrast. They are not of frequent 

 occurrence, but may occasionally be seen in fresh exposures espe- 

 cially in deep railroad cuts. Unfortunately they are quickly 

 effaced by weathering and by growing vegetation. The most 

 notable examples are found in the Milford cut-off of the Burlington 

 Railroad, particularly at Pleasantdale. For a mile or so west of the 

 station at Pleasantdale, especially on the right bank, fine examples 

 occur in almost continuous succession (see the accompanying sketch 

 and photograph). 



The drift at this place is a jointed sandy clay of a rusty gray 

 color, of a fairly compact texture, and about twenty-five feet in 

 thickness. It is somewhat .startHng to find in it great stray 

 blocks of various materials. These blocks are generally large 

 and angular or rounded masses of incoherent soil, sand, and 

 gravel, more or less stratified, cross-bedded, and tipped at all 

 angles. It is still more surprising to find sections of small stream 

 beds and channel deposits tilted and overturned. The dense 

 quartzitic and occasional granitic bowlders characteristic of the 

 Nebraska drift, and these incoherent sand and gravel blocks occur 

 together. Perhaps the arenaceous and argillaceous blocks were 

 likewise dense and coherent at the time of transportation and 



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