ii6 



GEORGE F. KAY AND J. NEWTON PEARCE 



Feet . Inches 



2. Glacial tiU (Nebraskan), oxidized, apparently- 

 leached, but has calcareous concretions, upon 

 which are films of manganese dioxide 2 



1. Glacial tiU (Nebraskan), unleached, oxidized, 

 light-yeUowish color on dry surface, mottled 

 brownish with gray when damp, many cal- 

 careous concretions, expecially in upper ten 

 feet 17 



D. Section in bluff north of Fort Madison, Lee County, Iowa: 



Feet Inches 



4. Loess and loesslike clay, grayish-yellow to 

 buff-yellow 7 



3. Gumbotil (lUinoian), drab to dark color; 

 starchlike fracture; few pebbles; leached. ... 4 6 



2. Glacial till (Illinoian), oxidized, leached. ... 6 

 1. Glacial tiU (lUinoian), oxidized, unleached to 



base 15 



Chemical analyses of the Nebraskan, Kansan, and Illinoian 

 gumbotils and their substrata. — The analytical data obtained from 

 the chemical analyses of samples taken from localities at "A," 

 "B," "C/' "D" have been collected in the following tables. 

 The results are given in two forms, (a) the percentage composition 

 with respect to the less mobile constituents, (6) the parts by 

 weight of these constituents per 100 parts of the more resistant 

 AlA- 



TABLE I 



A. Chemical analyses of Kansan gumbotil and oxidized and leached Kansan till 

 from cut on the Chicago, Milwaukee & St. Paul Railway about one mile east of 

 Foster, in the southeast comer of Monroe County, Iowa. 



