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6. NORTHWEST TO ALBERTA
The Old Course of the Milk River
At this point we travel west, to the city
of Shelby, Montana. Traveling along U.S. Highway 2 we notice
that Shelby, too, is located in a big valley, without any significant
large river. A traveller going northward along Interstate 15 would
notice the valley as a great dip; it is fitting that the photograph
shows the freeway in the foreground [N48° 36.74', W111° 52.56',
site 13]. In this case the valley is not very regular, and its
width is quite variable. It seems to come from the north, and
approach the city from the west. The irregularity of the valley is
a clue that a large river may have flowed through here only
briefly. The irregularity of the valley may also be due to its
age; if it was formed before the last ice age, there may have been
substantial erosion of the edges. It appears that this was a
temporary channel of the Milk River, when it was deflected from
its northeastward course by ice, and had to flow southward to drain
into the Marias River, which runs south of Shelby.
See detail map
Travelling north on Interstate 15 from Shelby we see signs of
glaciation and an old river valley, but they are never as clearly
defined as the valleys of the Missouri. Continuing north
on Canada Highway 4, we cross the Milk River at the town of
Milk River. The valley here is not very impressive, suggesting
that here is the original channel of this minor river. Traveling
east from Milk River, we come to the Writing on Stone Provincial Park,
which has some impressive badland topography [N49° 9.2', W111°
33.7', site 14]. Though the river seems to be back in its old
valley, such badland formations are an indication of young
topography. It is not certain why these formations are where
they are; further to the southeast are more badlands where it is
clear that the Milk River has had to cut a new channel.
One plausible reason for the badland topography has to do with the
general elevation of the terrain along the U.S.-Canada border.
Perhaps this area has been subjected to continuing uplift. The
ridge culminates in the Cypress Hills. The soils are also quite
soft and poorly consolidated. It is possible that the glaciers
removed so much soil that the Milk River had to excavate a new valley,
even though it was following its pre-glacial course here.
See detail map
Further east we come to a
spectacular depression in the terrain. Here [N49° 21.5', W111° 5.8',
site 15] is the pre-glacial channel of the Milk River. It is
impressive because the Milk River had encountered the rise of the
Cypress Hills, and was forced to cut deeply into the terrain to go
around them. At this point the river turned northward to join what
is now the South Saskatchewan River. The present day Milk River
has been diverted to the south of the Cypress Hills to join the
Missouri. The valley we see here is quite arid, and contains
nothing but some small streams and several small brackish lakes.
The size of this empty valley suggests that the Milk River was at one
time a quite powerful river. The broad valley here has also been
enlarged by glaciers.
If we continue eastward
around the south of the Cypress Hills we will encounter the Frenchman
River. This is another modest sized river that may once have been
more powerful than it is today. Near the town of Eastend,
Saskatchewan are kaolin mines [N49° 49.2', W108° 59.4', site 16],
from which the river derived its local name of the Whitemud River.
See detail map
The Frenchman River is also interesting because it is the northernmost
tributary of the Missouri River system. The source of the Frenchman
River is at N50° 13.6', W109° 7.7'.
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We are far from the path of the Lewis and Clark expedition, but the Frenchman River—though they never saw it—may play an important role in their concept of the geography of the rivers. The explorers were very confused about the reports of rivers they received from the Indians. One of the rivers they expected to encounter was the "White Earth River." They applied that name to an insignificant river in North Dakota, and then, when they encountered the Marias River, had to account for one more river than they had expected. The picture of the rivers makes sense only if the Milk River was known to (some of) the Indians as the White Earth River. The Frenchman River is the most important tributary of the Milk River, and the Indians' name for the river could have been derived from the Kaolin deposits in the Cypress Hills. The Indians would have been very aware of an important resource, such as white clay (which is not found near the present White Earth River). To them the more important branch of the river might have been the one they followed to obtain white clay. So the river known to the Indians as the White Earth River was the Frenchman-Milk River system. The Frenchman River is also known locally in Saskatchewan as the Whitemud River. As some historians and geographers have suggested, the Marias must have been the river the Indians knew as "The River that Scolds All Others." |
The Frenchman River also flows in a new, post-glacial
valley when it heads southward to joing the Milk River. About 14 mi
(22 km) west of the place where the Frenchman River crosses the
U.S.-Canada border is a broad valley, occupied by small lakes and
insignificant streams. This was probably the pre-glacial course of
the Frenchman River. Instead of following this easy route the
Frenchman River cuts through a high ridge. At some points [N48°
56.18', W107° 23.73', site 17] its valley is nearly 590 ft (180 m)
deep. Of course the glaciers must have had something to do with
the river shifting its course. The viewpoint of the photograph
is accessible by a four-wheel drive vehicle.
See detail map
But why should this river have shifted its course toward the northeast, when
all the other rivers were displaced to the south? There are no easy
answers, but the Milk River also seems to have been befuddled by that
broad valley where the Frenchman River once flowed. One possible
answer is that the valley was occupied by a huge block of
stagnant ice, long after the rivers had begun to flow again.
Such a mass of ice could have forced the Frenchman river to go around
it. As mentioned above there is a long topographic ridge along
the U.S.-Canada border, running from the Rockies almost to the North
Dakota border. If the only low place in the ridge was blocked by
ice, the Frenchman River would have had to cut through the ridge.
Next, back to the Milk River East of Havre
Photographs by G. Davidson