East of Glasgow the Missouri Valley is very broad and level.  If we were to continue past the town of Culbertson we would find that U.S. Highway 2 veers away from the river, but at Bainville one can take a local road that follows the river.  Here again we find what appears to be a narrow, young valley.  Indeed this is a "new" channel of the river.  The pre-glacial course of the Missouri headed off to the northeast, but there has been no obvious sign along the way of a large, abandoned valley.
See detail map
We can take a detour as far as Bainville and the North Dakota State Boundary, or we can turn off to the north at the town of Brockton, to explore the former route of the Missouri.  There is a local road, Rural Highway 344, that leads northward, crests a hill, and suddenly reveals a huge valley.  It seems that the glaciers have piled up debris at the southwest end of this valley, so the joining of the old and new valleys is obscured.  This is rather strange, and may indicate that the Missouri here was diverted in a previous ice age, long before the Last Glacial Maximum (LGM).  The best way to see more of this pre-glacial valley is to continue north, for 15.4 mi (24.4 km) from the junction at Brockton to an intersection with an un-numbered east-west road.  A right turn takes us back through the valley.  At the town of Froid we go north on Montana Highway 16 to Medicine Lake.
There are dozens of shallow lakes in this broad pre-glacial valley.  Medicine lake [Site 24] is the largest of these lakes, its size indicates that the slope of the valley at this point was rather low, and that the ancient Missouri had become a rather sluggish river, rather like the lower reaches of the Saskatchewan Rivers and the Red River.  Moreover, the land around Medicine Lake has been very extensively excavated by glaciers, which not only leveled off the former land surface, but deposited huge moraines and piles of boulders.
To the northwest of Medicine Lake the ancient valley has been nearly
obliterated by debris from later glacial advances.  The pre-glacial
Missouri River crossed the U.S.-Canada Boundary somewhere north of
the town of Noonan, North Dakota.  To the north the landscape again
becomes flat.  To the south is the great mass of boulders and
gravelthe Missouri Coteauwhich was piled up there at the
margin of the glaciers
If we head east from Medicine Lake
to U.S. Highway 85, just across the border in North Dakota, we come to
another misplaced valley, with only a small underfit stream meandering
southward along its floor.  This valley of Little Muddy Creek
becomes clearer and more pronounced as we head south toward the city of
Williston.  There is a particularly good view of the tiny stream
and the valley from the road east to Epping [Site 25].  This is the
ancient valley of the Yellowstone River, on its way north to join the
Lewis and Clark were quite puzzled by the numerous rivers they encountered on their journey through this region.  Though we know now that they arrived at a time of relatively high precipitation, there is no accounting for the excessive sizes and importance they gave to some of these streams.  They were not certain whether Little Muddy Creek was actually the White Earth River for which they were searching.  They seem to have missed the stream now called the White Earth River.  They did claim that Little Muddy Creek was a broad river, navigable for a large distance to the north.  Today we would have a difficult time navigating this stream with a canoe.
A side trip to visit Fort Union is worthwhile because it is a good place to view the meeting of the valleys of the Yellowstone and Missouri Rivers.  The original fort [Site 26] was established in the 1820's at a strategic location to intercept trade along both rivers.  What is most interesting about the geography here is that the Yellowstone Valley is immense, while the Missouri enters from the west through a quite narrow, young valley.  The rugged Missouri Valley can be best seen by a short detour, several miles wast of Fort Union.  This is clear evidence that the Yellowstone was the orginal owner of this territory.
Fort Union was constructed on the north bank of the Missouri River.
In the nearly 180 years since that time, the channels of the rivers have
all changed.  The Missouri River now flows nearly a mile away from
This is a good point to review the different types of valleys we have encountered along the way.  The cross sections of the present Missouri and Milk River Valleys are shown at various points: Fort Benton, Big Sandy, Havre, Harlem, Hinsdale, and Culbertson.  It should be apparent that the cross sections fall in two types (notice the exaggeration of the vertical scale):
A good way to see more of the present day course of the Missouri River, and its relatively young topography is to continue eastwards on North Dakota State Highway 1804.  A very interesting stop is at White Earth Creek (or River).  The valley is a geological curiosity worth exploring [Site 27].  Here is a small river in a gigantic, meandering valley, about 5 mi (8 km) broad.  The stream is tiny, and flows barely 50 miles (80 km) from small lakes atop the Missouri Coteau.  The valley exhibits broad meanders and the stream runs along the center of the valley.  Those giant meanders are a sign that they were formed by very large river; which cut deeply into the terrain.  After that river dried up or turned to another channel, the valley was left with only a tiny stream that has only slowly continued the erosion process.
The White Earth valley is quite similar in form to the Shonkin Sag in Montana, and it could have been an overflow channel for a large lake.  Here, however, there is no evident source for a large overflow stream.  We can't even be sure of what direction the stream was flowing.  It might have flowed toward the north, to drain a lake temporarily formed by the Missouri, or it might have flowed to the south to drain a lake formed by melting ice.  It doesn't seem to be an overflow channel for a river or lake in the north, since the stream has its origins in the highest part of the Coteau.  That problem might be overcome if we imagine a large lake formed during an early ice age, the evidence for which has been covered up by debris from the most recent ice age.  The best we can say about the White Earth River is that its valley was created in an earlier Ice Age, and the evidence has all been erased by the most recent Ice Age.
See detail map
The Missouri River in North Dakota has been dammed up, to form huge Lake
Sakakawea, so there are fiew places to see the valley floor.  It is
clear that the terrain is quite young.  In fact several channels
of the Missouri, dating to various pre-glacial and glacial times have
been located in North Dakota.  Just before reaching the town
of New Town, North Dakota, there is a fine view of the lake [Site 27],
filling the valley from side to side.
|Start, Nashua, Hwy 2||0.0||0.0||N48° 8.26'||W106° 21.37'|
|Brockton, Rural Road (left turn)||62.6||100.7||N48° 8.96'||W104° 55.19'|
||65.2||104.9||N48° 10.87'||W104° 56.09'|
|Rural Road (right turn)||77.6||124.9||N48° 21.64'||W104° 55.90'|
|State Hwy 17 (left turn)||98.2||158.0||N48° 21.33'||W104° 29.88'|
|Local Road (right turn)||108.4||174.5||N48° 29.15'||W104° 29.86'|
|  Medicine Lake Overlook||110.8||178.3||N48° 29.03'||W104° 26.91'|
|Return to Hwy 17 (right turn)||182.1||113.1||N48° 29.15'||W104° 29.86'|
|Rural Road (right turn)||184.3||114.5||N48° 30.30'||W104° 29.68'|
|Rural Road (left turn)||208.1||129.3||N48° 29.89'||W104° 10.41'|
|U.S. Hwy 85 (right turn)||266.8||165.8||N48° 34.18'||W103° 37.51'|
|Epping Road (right turn)||298.5||185.5||N48° 17.09'||W103° 37.54'|
|  Little Muddy Valley Overlook||305.5||189.8||N48° 17.00'||W103° 32.05'|
|Return to U.S. Hwy 2 (left turn)||309.3||197.1||N48° 17.09'||W103° 37.54'|
|Continue on Hwy 2 to Jct. 1804
|325.3||202.2||N48° 8.38'||W103° 46.65'|
|  Fort Union||343.3||202.2||N47° 0.00'||W104° 2.62'|
|Return to Williston, continue to Hwy 1804||369.8||202.2||N48° 8.88'||W103° 35.89'|
|  White Earth River||446.8||246.6||N48° 12.70'||W102° 46.79'|
|  Missouri Overlook||474.3||263.7||N48° 4.43'||W102° 36.72'|
|End, New Town||490.9||274.3||N47° 58.77'||W102° 29.59'|
Next, the Missouri Coteau in North Dakota
Photographs by G.  Davidson