Our tour has arrived at the Missouri Coteau, so it would be worthwhile to take a closer look at this feature.  North Dakota has probably more interesting glacial features than any other place in North America; but that story has to be deferred for the moment.  We are mainly interested in the relations to the history of the Missouri River.
Missouri Coteau is a large wedge of debris left by glaciers which advanced
across North Dakota wiping the lower land clean and flat.  It runs diagonally
from the northwest corner of the state to the center of the southern
border.  The glaciers did advance over the Coteau, but they mostly
stagnated and left huge deposits of gravel and rocks.  Gravel and
rocks are evident everywhere on the Coteau.  To be able to plow the
ground for crops farmers had to gather up the surface rocks and pile
them up in the fields.
See detail map
Travelers don't always notice
when they pass from glaciated lowlands to the Coteau.  In some
places, however the edge of the Coteau is marked by an abrupt
escarpment.  On State Highway 11 west of Ellendale one passes
across what appears to be a relatively flat prairie, marked by several
small streams.  This is in the path of the James River Lobe of the
Ice Age glaciers.  Quite suddenly one climbs 404 ft (123 m) up to
the top of the Coteau [N46° 1.78', W98° 57.11', site 30], with a
grand view of the terrain to the east.
The landscape atop the Coteau is entirely different from that on the glaciated plains below.  The transiton is not so sharp everywhere but generally the margins of the Coteau are littered with pothole lakes and rocky soil.  The photograph shows a lake quite close to the escarpment [N46° 1.58', W98° 53.92', site 31].  The few farms are obviously not very prosperous.
Early in the 20th century the Missouri Coteau in northwest North Dakota
was the site of a homesteading boom.  Though fertile soils can be
found, the rocks and boulders and marshes make them difficult to
cultivate.  By the mid century the boom was long past, and many of
the small towns that sprung up were dying.  Those who were forced
out must have appreciated the irony that one of the richest oil fields
in North America was discovered here just as the 20th century reached
its mid-point.  Immense amounts of oil were trapped in the deepest
part of the Williston Basin, which is centered near the city of
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Photographs by G.  Davidson