250 
IOWA ACADEMY OF SCIENCE 
(1) The Dakota plain has a slightly rolling to gently rolling sur- 
face, with a relief of 15 to 25 feet, while the region to the north, east 
and southeast, is rugged with a relief of 100 to 150 feet. 
(2) The Dakota plain has an altitude that is 50 to 100 feet below 
the altitude of the divides of the adjoining regions to the north, east 
and southeast. 
(3) The relief features of the Dakota plain consists largely of low 
mounds and broad swales, interspersed with shallow undrained depres- 
sions. Such erosion valleys as occur are narrow and steep-sided and 
have determined the topography of only a narrow belt on either side. 
This is a true glacial surface and the time which has elapsed since its 
formation is comparatively short. There is no Kansan area known that 
has such undrained depressions. The relief features of the adjoining 
region are those produced by erosion by running water to the sub-ma- 
ture stage of the cycle. 
(4) The Dakota plain is free from loess, while the region to the 
north, east and southeast has a loess covering. 
(5) Boulders and boulderetts are frequently seen on the Dakota 
plain, while in the area to -the north,, east and southeast, boulders are 
seldom seen, except in the beds of ravines that are being actively de- 
graded. 
(6) The Dakota plain has a dark pebbly, gritty soil, while over the 
surrounding area there is a pebbleless loam derived from the loess. 
This combination of characters found on the Dakota plain calls for 
an entirely separate glaciation at a very recent geologic time. The 
conclusion then is, that the plain extending from just north of the north 
line of Lincoln county, south through Shindlar and Harrisburg to the 
upland south of Canton, and east to the Big Sioux valley, was covered 
by a part of the Dakota lobe of the Wisconsin ice-sheet, and is a Wis- 
consin drift-plain, while the areas to the north, east and southeast be- 
long to the loess-covered, maturely-eroded Kansan drift-plain. 
