Geological Survey Bulletin 611 Guidebook of the Western United States: Part A

A few miles west of Eldridge (se sheet 6, p. 46) is the eastern front of a low plateau known as the Coteau du Missouri,¹ which is mentioned in all the accounts of early explorations in this part of the country. Doubtless in passing across the loomed up as a formidable obstacle, but the railway traveler of to-day, unless his attention is particularly directed to it, would probably cross it without realizing that it is a prominent topographic feature.

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¹Coteau is a French term signifying a small hill or hillock. In the northern part of the United States it was generally applied by the early French travelers to a range of hills or to the escarpment forming the edge of a plateau. Such an escarpment is usually dissected, so that at a distance it resembles a range of hills. The Coteau des Prairies and Coteau du Missouri are escarpments of this character.

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SHEET No. 6. (click on image for an enlargement in a new window)

At milepost 103 the train begins the ascent of the east front of the Coteau, and it reaches the summit just east of Windsor. A comparison of altitudes shows that this summit is almost exactly 300 feet above Eldridge and 435 feet above Jamestown. In a mountainous region a ridge 300 feet high is hardly worth considering, but in eastern North Dakota a plateau of this height is of the first magnitude. The commanding position of the Coteau can better be appreciated by a view eastward from milepost 108, at the east end of the deep summit cut. This view commands a wide expansion of undulating plain, which is backed in the distance by the low swell of Alta Ridge, east of Valley City.

As shown on the sketch map on sheet 5 (p. 44), a small moraine marks the face of the Coteau north of the railroad. It is probable that this is represented by the deep till in the summit cut east of Windsor, but the features visible from the train are not strikingly morainic in character.

The glacial features along the line of the railway are not well marked, from Cleveland nearly to Medina there are many indications, in the form of hummocks and undrained basins, of the morainic character of the topography. Beyond the belt the country is gently rolling. The scarcity of ranch houses is an indication that this is what was formerly called the "short-grass country," but now, in the days of successful dry farming, it has achieved a very different reputation.

Near Crystal Springs the aspect of the country appears to be distinctly moraine in character, but no definite ridge can be seen from the train. The tracks cross the Gary moraine (see sketch map on sheet 5, p. 44) a short distance west of this town, but as the railway follows an old outlet channel, the moraine, as seen from the train, does not appear to be particularly prominent. A mile or so to the left (south) of the track the moraine is strongly developed, consisting of a ridge at least 125 feet higher than the plain on the west. The gravel showing in big pits near Ladoga is outwash material from the front of the ice when it built the moraine.

Beyond Crystal Springs the country is drift covered but generally flat. This topography continues to Tappen, a flourishing village in a belt of good farming land. Seemingly the glacier in passing over this country had little effect except to smooth off and fill up most of the irregularities in the old topography.

In the vicinity of Dawson the most pronounced geologic and topographic feature is the Altamont moraine, which was produced by the Wisconsin ice sheet at the time of its maximum extension. As shown on the sketch map on sheet 5 (p. 44), there is a great reentrant angle in this moraine almost due east of Bismarck, at about the place where it is crossed by the Northern Pacific Railway. Owing to this reentrant the moraine trends parallel with the track and is visible for several miles. West of Dawson there are heavy deposits of drift which probably belong to this moraine. They are especially prominent in a cut a mile long between mileposts 147 and 148.