THE ORIGIN OF GUMBOTIL 99 



Feet Inches 



4. Loesslike clay i 



3. Gximbotil (Nebraskan), grayish to drab on 

 dry surface; when damp, is grayish to brown- 

 ish; a few siliceous pebbles; leached 11 



2. Glacial till (Nebraskan), oxidized and leached, 



many disintegrated bowlders 4 6 



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

 concretions, exposed 3 



Near this exposure Kansan till overlies the Nebraskan gumbotil. 



Another interesting cut which shows Nebraskan gumbotil 

 and underlying drift is along the wagon road west of Osceola, 

 Clarke County, southwest corner of section 13, Ward Township, in 

 front of a schoolhouse. The section is as follows: 



Feet Inches 



5. Loesslike clay, gray to light-yellow 8 



4. Glacial till (Kansan), oxidized, leached, fer- 



retto zone on top 5 6 



3. Glacial till (Kansan), oxidized, unleached, 

 many concretions 8 



2. Gumbotil (Nebraskan), gray to drab-colored, 

 sticky when wet, tough when dry, some cal- 

 careous concretions, a few siUceous pebbles; 

 leached 10 



1. Glacial till (Nebraskan), oxidized, unleached; 

 except in narrow upper zone, many calcareous 

 concretions; bowlders and pebbles; above 

 base of exposure 25 



Southeast of New Market and near the middle of the north 

 boundary of section 5, Mason Township, Taylor County, Iowa, 

 is a fine exposure of Nebraskan gumbotil with Kansan drift above 

 it and Nebraskan drift below it. The section is as follows: 



Feet 



4. Drift (Kansan), oxidized and unleached, 

 many concretions 15 



3. Gumbotil (Nebraskan), gray to drab-colored, 

 leached, a few sihceous pebbles 8 



2. Glacial till (Nebraskan), oxidized, leached.. 3 

 I. Glacial till (Nebraskan), oxidized, unleached, 



many calcareous concretions, exposed 22 



