98 GEORGE F. KAY AND J. NEWTON PEARCE 



A good section to show the field relations of the Nebraskan 

 gumbotil to the underlying Nebraskan till is a railroad cut just 

 east of a viaduct i\ miles west of Manning, Carroll County, Iowa/ 

 From the surface the cut shows loess, Kansan till, soil band, 

 Nebraskan gumbotil, and Nebraskan till. The section is as 

 follows: 



Feet Inches 



6. Loess: 



Leached, yellowish-gray on dry surface; 

 yeUowish-brown to buff-brown on damp 



surface; no shells or concretions 7 



Unleached, lighter-colored on dry surface 

 than the leached loess, and when damp 

 is buff with gray streaks; contains shells 

 and concretions 5 



5. Glacial till (Kansan), yellow, unleached, with 

 calcareous concretions; numerous pebbles 

 including granites, quartzites, etc. Below 

 the oxidized, unleached tiU is gray till with a 

 few pebbles. It is gumbotU-like, but effer- 

 vesces freely. It was probably picked up 

 from the gumbotil zone below 5 



4. Soil band containing carbonaceous material . . 4 



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

 few pebbles. The upper 6 feet is fine grained, 

 gray, and is less sticky and gumbotil-Uke 

 than the lower 7 feet, which is leached but has 

 some calcareous concretions 13 



2. Glacial till (Nebraskan), oxidized, apparently 

 leached, but has calcareous concretions, upon 

 which are films of manganese dioxide 2 



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

 light-yellowish color on dry surface, mottled 

 brownish with gray when damp; many cal- 

 careous concretions, especially in upper 10 

 feet 17 



In Taylor County, Iowa, at a stream crossing just west of 

 Conway Station on the Chicago, Burlington & Quincy Railway, is 

 an exposure at which the following section was observed: 



^George F. Kay, "Pleistocene Deposits between Manilla in Crawford County 

 and Coon Rapids in Carroll County, Iowa," Iowa Geol. Surv., Vol. XXVI (191 7)) 

 p. 225. 



