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IOWA ACADEMY OF SCIENCE 
3. Clay, brownish blue with many hemispherical holes three to five 
feet in diameter apparently worn into its surface; a few 
pebbles up to three-fourth of an inch in diameter ; no gravel nor 
pebbles visible in bottom of holes (Gumbo; Dallas) 6 
2. (Line of pebbles seeming to mark a plane of erosion) ; clay, 
brownish, with many pebbles and bowlders of red quartzite, 
decomposed granite, etc (Kansan Drift) 3 
1. Shale, mostly clayey (Des Moines) 6 
The gumbo (numbers 3-4) is separated into two portions by a plane 
that seems to be a plane of disturbance rather than erosion or weather- 
ing. No pebbles appear in the hemispherical projections of number 4 
into number 3, as there would be if such places were potholes. The 
plane seems due to renewed advance of the Kansan ice. 
In Lucas county close to the county line (Nw. % of Ne. % of section 
2, English township) a steam shovel was at work cutting five feet deep 
into a dense blue clay beneath several feet of Kansan drift that con- 
tained characteristic bowlders and pebbles. One bowlder was a large 
bowlder of blue clay like the basal clay there found but also containing 
fragments of coal. This seems either a bowlder of Nebraskan drift, or 
a Kansan bowlder of Des Moines shale worked over and incorporated 
into the Kansan drift. In the latter case any evidence of stratification 
which the clay may have had when in the form of Des Moines shale had 
been lost. In the bottom of a trench a little further south is a somewhat 
similar dense bluish black clay with nothing separating it from the 
distinct Kansan drift seen in the hills. Several other somewhat similar 
cuts occur within six miles to the south toward Chariton in which the 
drift exposed is distinctly Kansan drift. 
At Chariton a good section is obtained by combining the outcrops 
found in the three cuts beginning at the crossing of the Chicago, Bur- 
lington and Quincy railroad and extending south to Chariton river. 
At the railroad crossing the two feet of soil is on the gumbo, the upper 
portion of which is here brown through oxidation, the lower portion 
gray, containing small pebbles especially of quartz and granite rarely 
over half an inch in diameter. Next, without any line of pebbles and 
underneath the above mentioned clay, is the brownish, weathered and 
bowlder-bearing phase of the Kansan drift, well exposed in the long cut 
two hundred yards to the south, where the exposure gives about fifteen 
feet filled with large sand bowlders and numerous and characteristic 
bowlders of decomposed granite, greenstone, quartzite, and brown, yel- 
low and red chert. In the trench by the river there is included a bed 
