932 ROLLIN D. SALISBURY 



apparent on approximately level surfaces, and that it is least 

 likely to be present on steep slopes. In general it does not 

 appear to be stratified, though where it is thick it is occasionally 

 marked more or less distinctly, with dark and light bands in an 

 essentially horizontal position. This variation in color is 

 probabl}^ the result of chemical changes since its deposition, 

 brought about by the concentration of coloring matter along 

 definite horizontal lines. The concentration along these definite 

 plains probably means some variation in texture along these 

 plains, and this probably points to stratification. 



As seen in section, the contact of the loam above with the 

 till below is usually irregular, but often sharply marked. Both 

 the regularity and the distinctness of the contact are more 

 striking between the loam and stratified drift than between the 

 loam and till. 



Where the loam overlying till attains a thickness of as much 

 as four or five feet the lower portion very commonly approaches 

 loess in character. Where the loam is thin, say two or three 

 feet thick only, it does not resemble loess, though it is not 

 unlike the uppermost two or three feet of clay-loam which over- 

 lies loess in regions where the latter has its more clayey and 

 less normal development. 



The suggestion of connection between the loam and loess 

 was given added force by finding loess at the two points men- 

 tioned, in just such situations and relations as that in which the 

 loam commonly occurs. 



Loess at Devils Lake. — East of the south end of Devils Lake 

 fresh railway cuts reveal the presence of loess on the terminal 

 moraine of the Wisconsin epoch. The crest of the moraine 

 along the line of the railway at this point is, according to the 

 topographic map, between 6o and 8o feet above the lake. The 

 loess may be seen on both the inner and outer slopes of the 

 moraine, but does not cover its summit, failing to reach it on 

 either side by about ten feet. 



While some of the loess here is thoroughly typical, it locally 

 grades, either horizontally or vertically, into clay which is very 



