2382 GEOGRAPHICAL MEMOIR. 
Its northern termination (called Tete de Coteau, in consequence of its peculiar configuration) 
is not more than fifteen or twenty miles across; its elevation above the Big Stone lake is 890 
feet, and above the ocean 1,916 feet. Starting from this extremity the surface of the plateau 
is undulating, forming many dividing ridges, which separate the waters flowing into the St, 
Peters and the Mississippi from those of the Missouri. Under the 44th degree of latitude the 
breadth of the сбісал is about forty miles, and its mean elevation is here reduced to 1,450 feet 
above the sea. 
The cóteau itself is isolated in the midst of boundless and fertile prairies extending to the 
west, to the north, and into the valley of the St. Peters. Dead Colt Hillock is one isolated 
butte standing north of the extremity of this cóteau, and probably at one time connected with 
it, as it has the same general structure. This butte was not measured, but others further west 
were found to rise 200 feet above the valley. The general region of the Bois de Sioux is very 
remarkable. It is a very extensive plateau, partly prairie and partly wooded, with a beautiful 
timber growth on the streams which intersect it, that separates the waters flowing into Hudson 
bay from those flowing into the Gulf of Mexico; and yet the divide is not perceptible to the eye. 
It is the natural key of railroad communications through Minnesota; and yet the Cóteau des 
Prairies, which may be said to be its southern limit, is both a landmark and a barrier. The 
country between the western' branch of the Shyenne and the Red River of the North is unsur- 
passed for pasturage, furnishes a large portion of arable land, and yet to its limits is at times 
rolling and hilly, and a portion of the land is of inferior quality. 
BOIS DE SIOUX TO MOUIH OF THE YELLOWSTONE. 
Westward from the region just described to the mouth of .the Yellowstone, there are some 
general features which I will first referto. "The Cóteau du Missouri stretches along the northern 
side of the Missouri river separating its waters from the northern system of waters which 
have their outlet in Hudson bay. It presents to the eye of a voyageur the appearance of a 
distant coast, and so easy and practicable is it that one can move with heavy trains over nearly 
all portions of it. "This cóteau, in the vicinity of the Yellowstone, passes to the northward 
and westward into British territory, and, continuing westward, finally blends itself in the pro- 
jecting spurs and main chain of the Rocky mountains, separating again the waters of the 
Missouri from the waters of the Saskatchawan. А great feature of the intermediate country is 
the Miniwakan, or Devil's lake. This lake is on the plateau of the Shyenne, and is surrounded 
by swells and hills, varying in height from 20 to 250 feet. 
The greatest extent of the lake is at least forty miles, but may be more, and is bordered on 
its south side by hills which are pretty well wooded. It is so filled up with islands and 
promontories that in travelling along its shores it is only by occasional glimpses that its great 
expanse is visible. 
Its average breadth may be set down at fifteen miles, and its waters appear to be the 
drainings of the surrounding hills. It has no outlet towards Red river except by a depression, 
by which in high water it may possibly discharge itself into the Shyenne. 
Its water is too brackish to be drank except by horses, which swallow it with avidity, and 
its color is a deeper green than the neighboring lakes, which are not salt. By analysis they 
were found to contain sulphates of soda and of magnesia, (epsom and glauber salts) and 
chlorides of soda (common salt) and magnesia. : 
Large fish of several kinds inhabit it. 
