Lewis and Clark Middle Missouri BigSioux James

The Coteau des Prairies is a

plateau In geology and physical geography, a plateau (; ; : plateaus or plateaux), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. ...

approximately 200 miles in length and 100 miles in width (320 by 160 km), rising from the

prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

flatlands in eastern

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...

, southwestern

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

, and northwestern

Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...

in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. The southeast portion of the Coteau comprises one of the distinct

regions of Minnesota The U.S. State of Minnesota is the northernmost state outside Alaska; its isolated Northwest Angle in Lake of the Woods is the only part of the 48 Continental United States, contiguous states lying north of the 49th parallel north. Minnesota is ...

, known as Buffalo Ridge. The tip of the feature starts in extreme south

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

. The flatiron-shaped plateau was named by early French explorers from

New France New France (, ) was the territory colonized by Kingdom of France, France in North America, beginning with the exploration of the Gulf of Saint Lawrence by Jacques Cartier in 1534 and ending with the cession of New France to Kingdom of Great Br ...

(

Quebec Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...

), ''coteau'' meaning "hill" in French; the general term ''coteau'' has since been used in English to describe any upland dividing ridge. The plateau is composed of thick

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

deposits, the remnants of many repeated glaciations, reaching a composite thickness of approximately 900 feet (275 m). They are underlain by a small ridge of resistant

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

. During the last (

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

) Ice Age, two lobes of the Laurentide glacier, the James lobe on the west and the Des Moines lobe on the east, appear to have parted around the pre-existing plateau and further deepened the lowlands flanking the plateau. The plateau has numerous small glacial lakes and is drained by the

Big Sioux River The Big Sioux River is a tributary of the Missouri River in eastern South Dakota and northwestern Iowa in the United States. It flows generally southwardly for ,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataTh ...

in South Dakota and the Cottonwood River in Minnesota. Pipestone deposits on the plateau have been quarried for hundreds of years by Native Americans, who use the prized, brownish-red mineral to make their sacred

ceremonial pipe A ceremonial pipe is a particular type of smoking pipe (tobacco), smoking pipe, used by a number of cultures of the indigenous peoples of the Americas in their sacred ceremonies. Traditionally they are used to offer prayers in a religious ceremo ...

s. The quarries are located at Pipestone National Monument in the southwest corner of

and in adjacent

Minnehaha County, South Dakota Minnehaha County is a County (United States), county on the eastern border of the U.S. state, state of South Dakota. As of the 2020 United States census, 2020 census, the population was 197,214, making it the state's List of counties in South D ...

. Numerous wind farms have been built on the area's surface to take advantage of the high average wind speeds.

Photos from North Dakota

File:CoteauDesPrairiesFromNorth.jpg, Northern tip of Coteau des Prairies, as seen from 139th Ave SE near Havana, ND File:CoteauDesPrairiesFromNortheast.JPG, Coteau des Prairies as seen from the northeast, near Lidgerwood, ND File:HeadOfCoteauDesPrairies-fromNE.JPG, The northern head of the Coteau des Prairies, as seen from the Northeast near Lidgerwood, ND.

References

External links

USGS Site
on the Coteau des Prairies
Glacial History
of Coteau des Prairies (

University of South Dakota The University of South Dakota (USD) is a public research university in Vermillion, South Dakota, United States. Established by the Dakota Territory legislature in 1862, 27 years before the establishment of the state of South Dakota, USD is t ...

). {{coord, 44.0000, N, 96.3167, W, source:wikidata, display=title Great Plains Plateaus of the United States Landforms of Iowa Landforms of Minnesota Landforms of South Dakota Landforms of North Dakota Ecoregions of Minnesota Regions of South Dakota