IOWA ACADEMY OF SCIENCE 
249 
There remains to be noted a few isolated hills which rise above the 
level of the Dakota plain near its eastern edge along the Big Sioux 
valley. They are located from south to north as follows: (1) At the 
northeast edge of Canton. (2) Three miles northeast of Canton. (3) 
Just opposite Klondike. (4) Tavo and a half miles east of Shindlar. 
Professor Todd refers to them as the only representatives of the Alta- 
mount moraine between the highland south of Canton and the ridge 
south of East Sioux Falls, and says that the larger of them ‘‘show 
basins indicating their morainic character, ” and that the hill in north- 
east Canton is “composed largely of gravel.” 7 Professor Shimek says 
concerning them “they are certainly Kansan, and are evidently related 
to the upland on the Iowa side. ” 8 Like the plain to the west they are 
not covered with loess and at least three of them have pebbles and bould- 
eretts on the surface. The drift of these hills, in so far as seen, could 
not be differentiated from that of the surrounding plain and is ap- 
parently Kansan. These hills were apparently features on the pre- 
Wisconsin surface, or remnants left by the erosion of the Wisconsin 
ice, but they were over-ridden by the Wisconsin ice, stripped of the 
loess- covering and A^eneered Avith a thin coating of drift with gravels 
and boulder etts on the surface. 
The results of this study would fix the extent of the Wisconsin drift- 
plain essentially as determined by Professor Todd. The writer does 
not however agree with Professor Todd concerning moraines at the 
edge of the Wisconsin plain. It has been shown that the features taken 
by Todd as the Altamont moraine, from a point opposite the north 
boundary of IoAva westward to the south end of the Great Bend are 
erosional hills and ridges of the Kansan plain just outside the Wis- 
consin boundary, and that the ridge running westward from the south 
end of the Great IJend is within the Wisconsin boundary Avith glacial 
topography to the north extending to the valley of Skunk creek. The 
isolated hills along the Big Sioux betAAAeen the north boundary of Iowa 
and Canton are apparently remnants of the Kansan plain made up of 
Kansan drift but over-ridden by the Wisconsin ice. It is also probable 
that there is little true terminal along the border southwest of Canton 
toward Beresford. 
In summary the evidence here submitted may be brought together 
as follows: 
7 Todd, J. E., Bull. 158 U. S. Geol. Survey, 1899, p. 34. 
8 Shimek, B.„ Bull. Geol. Soc. America, vol. 23, 1912, p. 150. 
0a Those parts of O’Brien and Osceola counties here referred to the Kansan may be- 
long to a post-Kansan, pre-Wisconsin drift sheet. 
