Coteau des Prairies

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The Coteau des Prairies: orange arrows indicate paths of the two lobes of the glacier around either side of the formation.

The Coteau des Prairies is a plateau, approximately 200 miles in length and 100 miles in width (320 by 160 km), rising from the prairie flatlands in eastern South Dakota, southwestern Minnesota, and Northwestern Iowa in the United States. The southeast portion of the Coteau comprises one of the distinct regions of Minnesota, called Buffalo Ridge.

The flatiron-shaped plateau was named by early French explorers from New France (Quebec). Coteau means "slope" in French.

The plateau is composed of thick glacial deposits, the remnants of many repeated glaciations, reaching a composite thickness of approximately 900 feet (275 m). They are underlain by small ridge of resistant Cretaceous shale. During the last (Pleistocene) Ice Age, two lobes of the glacier appear to have parted around the preexisting plateau and further deepened the lowlands flanking the plateau.

The plateau has numerous small glacial lakes and is drained by the Big Sioux River in South Dakota and the Cottonwood River in Minnesota. A quarry in the plateau was once the site for obtaining the traditional stone used in Native American peace pipes. Red pipe stone (catlinite), a fine-grained, easily-worked mineral was quarried near present day Pipestone, Minnesota and in adjacent Minnehaha County, South Dakota.

[edit] References

Coteau des Prairies

[edit] See also

Missouri Coteau

[edit] External links

USGS Site on the Coteau des Prairies
Glacial History of Coteau des Prairies (University of South Dakota).

	State of South Dakota
Capital	Pierre
Regions	Badlands \| Black Hills \| Coteau des Prairies
Cities	Aberdeen \| Brandon \| Brookings \| Huron \| Madison \| Mitchell \| Pierre \| Rapid City \| Sioux Falls \| Spearfish \| Sturgis \| Vermillion \| Watertown \| Yankton
Counties	Aurora \| Beadle \| Bennett \| Bon Homme \| Brookings \| Brown \| Brule \| Buffalo \| Butte \| Campbell \| Charles Mix \| Clark \| Clay \| Codington \| Corson \| Custer \| Davison \| Day \| Deuel \| Dewey \| Douglas \| Edmunds \| Fall River \| Faulk \| Grant \| Gregory \| Haakon \| Hamlin \| Hand \| Hanson \| Harding \| Hughes \| Hutchinson \| Hyde \| Jackson \| Jerauld \| Jones \| Kingsbury \| Lake \| Lawrence \| Lincoln \| Lyman \| Marshall \| McCook \| McPherson \| Meade \| Mellette \| Miner \| Minnehaha \| Moody \| Pennington \| Perkins \| Potter \| Roberts \| Sanborn \| Shannon \| Spink \| Stanley \| Sully \| Todd \| Tripp \| Turner \| Union \| Walworth \| Yankton \| Ziebach