By E. J. Babcock
Dean, College of Mining Engineering, State University, North Dakota
The topography of the Red River valley cannot be fully considered apart from that of the state as a whole, since the topography of the eastern part of the state blends into and forms a part of that of the central and western portion of the state. In common with most of the great prairie districts west of the Mississippi river, the Red River valley, and, indeed, North Dakota as a whole, presents no great extremes of altitude and no very marked feature of topography. Like a large part of the Great Plains, it is principally characterized by the vast expanse of nearly level or rolling prairies. In the main the land is well supplied with surface water by several river systems and numerous small lakes. The four most important rivers are the Red River of the North, along the eastern boundary of the state, the Missouri river in the western part, and the Sheyenne and James rivers in the central portion of the state. Nearly all the streams within the limits of North Dakota are sluggish, rather shallow, and often muddy. As might be expected from the geology, they lack the falls and cataracts and the sparkling character of the streams of a more rugged and rocky country.
The state, however, is not without a modest variety of surface features, for there is not only the very level plain of the valley of the Red River of the North and the districts west and southwest, but there is much beautiful rolling prairie, especially between the Pembina and Turtle mountains on the north and Sheyenne river on the south. Along the Souris and Missouri rivers, toward the northwest, are undulating plateaus, and in the southwestern portion of the state are the more extensively eroded surfaces, which in some localities present in miniature the wildness and picturesqueness of the Grand Canyon district of the Colorado. While no very marked natural divisions can be traced, the surface may in a general way be classified topographically as follows: Red River valley, Pembina and Turtle Mountain highland, central rolling prairie, and the western coteau of the Missouri.
The Red River valley lies along the eastern boundary of North Dakota and comprises a tract from twenty-five to seventy miles wide, extending across the state from south to north. This whole area is very nearly a level plain, rising slightly on both sides of the stream which gives its name. The river flows somewhat east of the central portion of this flat bottom in a general course from south to north. Its channel is winding, as is common to streams flowing slowly through clay and other easily eroded material. The banks of the stream, which are mostly of fine silt and clay, rise rapidly on both sides to from fifteen to forty-five feet above the water. Most of the tributaries are small and cross the plain in similar channels, which frequently widen out in the spring into little ponds, that nearly always become dry by early summer. The drainage is gotten principally by these tributary gullies, which, though small, are of great advantage in carrying the spring floods and, later in the season, in furnishing good pasture land.
The valley has a very uniform descent toward the north, but so slight as to be entirely imperceptible to the eye. The inclination usually ranges from about six inches to two feet to the mile.
At Wahpeton the surface is about 960 feet above the sea level; near Fargo, 900 feet; near Grand Forks, about 830 feet; and at the international boundary, about 790 feet. Toward the west the ascent from the river is somewhat more rapid, averaging from 50 to 75 feet to the mile for the first 25 miles. Near the boundary line a distance of 30 miles west of the river brings one to the edge of the valley at the Pembina mountains, which rise from 300 to 350 feet above the surface. West of the river from 25 to 50 miles the ascent becomes quite rapid as the various ridges of the glacial deposits are passed, until, going beyond the Red River valley, the central portion of the state is reached.
The Red River valley is immediately underlain by alluvial clays, modified drift, sand and gravel. With this remarkably strong subsoil and equally remarkable deep and rich upper soil, there is good reason for the fertility which has characterized this region. A large variety of prairie grasses grow with great luxuriance in this valley, but it is especially noted for its large yield of superior quality of wheat. There is considerable timber skirting the banks of the Red river, but very little away from the stream.
Going west about thirty miles from the Red River of the North near the international boundary, one reaches an area rising abruptly from the gentle inclination of the valley to a height from 400 to 600 feet above the Red river. This elevated land stretches many miles northward into Canada, and southward forms a gradually descending plain far into the central part of the state. In its northeastern portion this elevated tract is known as the Pembina mountains. Toward the west the elevation increases slightly, occasionally interrupted by low land, until it practically unites with the Turtle Mountain highland west of the Pembina mountains. Topographically, as well as geologically, these two elevations should be considered together.
Along the northern part of the eastern slope of the Pembina mountains the elevation presents the appearance of a prominent wooded bluff, rising from 250 to 350 feet above the surrounding level, and extending in a nearly direct line toward the south. This ridge gradually decreases in elevation, until at its southeastern extremity it is scarcely more than fifty feet above the country around, and then it is lost in the rolling prairie. Along the eastern edge of the escarpment the elevation above the sea ranges from about 1,100 feet in the eastern part to 1,500 feet in the northwestern.
The eastern face of this escarpment is frequently scarred by deep transverse ravines running back from the edge of the hills from one to fifteen miles toward the west. Nearly all of these valleys are covered with small timber, and in the spring contain small streams, which in most cases become nearly dry in summer. Along the sides of these gullies are numerous springs of good water (usually slightly impregnated with Sulphur and lime. In summer these springs become the main supplies which keep up the brooks. There are only three or four streams worthy of mention along the eastern slopes of the Pembina mountains. In the northern part the Little Pembina has cut a channel through the drift and clay from 50 to 350 feet in depth. This stream flows about ten miles east and from four to six miles north into the Big Pembina river near the international boundary line. For most of its way the stream occupies a very narrow, winding bed in a valley from one-quarter to one-half mile wide, and usually 300 feet or more deep. The stream is fed for a large part of the year by numerous springs. The ravine through which it passes is well supplied with small timber (cottonwood, poplar, and oak). There are many charming views along this stream.
A few miles south of the Little Pembina river is the Tongue river, which presents general characteristics much like the Little Pembina, but which flows a much shorter distance through the Pembina highland. Ten or twelve miles south of the Tongue river is the north branch of the Park river. The three branches of the Park flow through the descending southern portion of this elevation and, as would be expected, have shallower and narrower banks and much slower currents. The banks have but few trees.
The most important stream of this region is the Pembina river, which flows through the mountains near the international boundary line. This river rises far to the west, near the Turtle mountains, and flows in an easterly direction, through Manitoba and North Dakota, into the Red river near the town of Pembina. In a direct line this distance is probably 120 miles or more, but by the actual length of the stream it is much greater, since its course is quite circuitous. A large portion of its channel has been cut through the Turtle and Pembina Mountain highland. Its banks are from 50 to 350 feet high, and the valley varies in width from a few rods to nearly a mile. Along the deepest part of the valley, toward the eastern part of the Pembina mountains, the banks are high and rugged and well covered with small trees. At Walhalla the river flows out of the higher part of this elevation, through a low ridge of drift and clay, into the Red River valley. From Walhalla back several miles to what is known as the ”Fish Trap” the river has a very rapid current. At the latter place there is a good water-power, and at Walhalla a small part of the power is utilized for milling. From its source to Walhalla the river falls about 700 feet, and from Walhalla to the mouth, about 185 feet.
From the ravines of the streams along the eastern edge, bordering the Red river, the crest of the Pembina mountains forms a treeless, rolling plateau stretching away toward the west. Over most of this tract, between the Pembina and the Turtle mountains, a distance of about 100 miles, there is very little to note except that it is a high prairie. There are but few streams and lakes, or other marked surface features. This whole region is usually productive of good crops of small grain. This section is well supplied with a variety of excellent prairie grasses. Toward the western edge of this belt there is a gradual elevation approaching the Turtle mountains, and a slight descent toward the south. The .southern slope shows a very gentle drainage system, beginning near the base of the Turtle mountains, and becoming more pronounced as it extends farther into the Devils Lake basin. In fact, this basin is the natural drainage reservoir for the waters of the larger part of the northern highland just discussed. There are no streams worthy of mention along the western part of this district, except those which, like the Pembina river, have their sources on the northern side of the Turtle mountains in Canada. While there is no river drainage to the south worth mentioning, there is certainly a great surface and subsurface drainage toward the south. Doubtless much water slowly percolates through the drift and upon and in the cretaceous clays from this elevation toward the basin in which Devils Lake is situated.
The Turtle mountains proper form a high rolling plateau about forty miles long by thirty miles wide, its longer axis being east and west. The surface rises gradually from all sides, but within one or two miles the elevation suddenly increases until it reaches a height of 300 to 400 feet above the surrounding country. The sides of the hills are nearly treeless, but among the hilltops there is a good deal of small timber. The Turtle mountains present a very broken outline on account of the large number of subordinate hills and ridges. The highest of the buttes reaches an elevation of perhaps 2,000 feet above the sea, or 600 feet above the surrounding country. The top of the mountains has a beautifully rolling surface covered with trees and dotted with lakes and ponds. Many fine farms are located here. Near the central part of these hills is the attractive little Lake Metigoshe.
The Turtle mountains consist of a mass of Cretaceous and Laramie slates and clays which have escaped erosion and are covered with a thin layer of drift material. This material is, however, somewhat cut out on top of the plateau, and thus is formed a great gathering reservoir. No doubt a large amount of the water flowing in the brooks and from the numerous springs has gradually seeped through the clays and sand to the hillside, where it emerges as springs. The Turtle Mountains district certainly is to a greater or less degree connected with the underground water supply of the prairies to the south.
Looking toward the south from the heights of the Turtle mountains, one has spread out, 400 feet or more below him, a beautiful view of a gently rolling prairie region dotted with small farm-houses surrounded occasionally by planted groves. As far as the eye can reach, this undulating surface extends, gradually decreasing in elevation as it approaches Devils Lake. From points farther east, toward the Pembina mountains, a similar though less marked descent toward the south is noticeable. So, as has been said, the Devils Lake region becomes the natural gathering basin for this northern highland district. This basin has flowing into it only small streams, for the most part coulees, which often become dry in the summer. There are very many of these shallow water courses, now mostly dry, which were doubtless at one time very important factors in draining the northern district and in maintaining the supply of surface water in and about Devils Lake. When the land was thickly covered with prairie grass, the latter apparently served as a thatch, which prevented the water from soaking into the soil. This, of course, allowed more water to accumulate in the coulees, and eventually in the lake basin. As the land was put under the plow, more of the water which fell as rain percolated through the soil, and a smaller proportion ran away as surface water. Thus there seems to be good reason for the noticeable decrease in the quantity of water in the lakes and ponds of this region.
Many of the coulees originate in the Turtle mountains and flow toward the south, but their course is generally very winding. They vary in size from wide sags only two or three feet deep, to narrow channels 50 to 100 feet wide and with banks 25 feet high. When water is not flowing through them, small ponds are frequently left. The wider portions usually make valuable hay and pasture lands.
In the northern and northeastern part of this region the streams cut through a rich and rather clayey soil and a strong blue-clay subsoil which is largely mixed with drift material. Toward the west, from Cando to Eugby, and for some distance west and south of Eugby, the surface is somewhat more rolling, and the soil has a larger proportion of sand. The natural drainage of this region is toward the southeast, and from Eugby there is a well-marked drainage to the Sheyenne and James rivers. This old tributary to these rivers is now usually dry. There are, however, a few ponds and lakes left, notable among which is the Girard Lake, a body of water perhaps three miles long and from one mile to two miles wide.
Girard Lake and several smaller lakes, which were evidently at one time parts of it, show in many places, by their marked shore lines and deposits, a period when the water was from ten to thirty or forty feet higher and spread over an area several times as great as that now occupied. This old lake had a very irregular shore line; its length was probably greatest from northwest to southeast. In many places now several feet above the water level are two or three lines of boulders and gravel, and occasional stumps of silicified wood. There is no doubt that this lake had its outlet to the Sheyenne river and upper feeders of the James river. That these conditions remained nearly constant for some time is evident from the character of the old shore deposits as well as from the banks of the upper Sheyenne river.
By far the most characteristic feature of this part of the state is Devils Lake and surrounding country. The lake lies along Ramsey and Benson counties, with its length extending east and west. Taking the lake with its arms, some of which are nearly dry or separated by portions of land, but which properly belong to the lake, the length would be about twenty-four miles and the width average perhaps between four and seven miles. There was unquestionably a time, early in the history of the lake, when it occupied two or three times its present area. The old shore lines indicate that its water level must have been from twenty to forty feet above that of today. Now the water is from twenty-five to thirty feet deep, away from the shore, as indicated by a number of soundings. The southern shore of the lake, which is often thickly strewn with large boulders, rises rather rapidly into a high, rolling country whose surface is broken by numerous steep knobs, some of them 200 to 275 feet above the water level. The western part of this tract is included in the Sioux Indian reservation. The northern, western, and eastern shores rise gradually from the water’s edge, for several miles back from the lake. The old lake extended much farther north and west, as may well be seen by the old bays which are now dry or are only moist enough for good meadows. The lake is now fed by the immediate surface drainage, which is usually carried by a few coulees. A large part of the water which formerly drained into the lake from a distance has been cut off by the cultivation of the prairie land. As a result, the shallower parts of the lake have, within the last fifteen years, dried up, and the water area has thus been very much reduced. It does not seem probable, however, that a proportional decrease will follow within the next fifteen years.
The central portion of the state south of Devils Lake is drained by the Sheyenne and James rivers. The Sheyenne rises about thirty miles west of Devils Lake and flows in a very winding channel for about 900 miles toward the east; then it takes a course nearly due south for about 100 miles, until, twenty miles or so from the southeastern limit of the state, it turns northeasterly into the Red River valley and empties into the Red river a short distance above Fargo. It will thus appear that the Devils Lake region has in a way its ultimate drainage into the Red River valley. For the greater part of its course the stream is narrow, its channel being cut through yellow and blue clay. Often the banks are strewn high up on the sides with glacial debris. They vary greatly in height, from a few feet near the mouth, to eighty or ninety feet near the upper waters. Along parts of the river course there are well-marked terraces, which were doubtless formed when the stream was an outlet for the glacial lake region to the north. The western part of the country drained by the Sheyenne river is a high, rolling prairie, often from 1,300 to 1,600 feet above the sea. The soil is very rich and, when there is a fair amount of rainfall, produces an abundant crop.
Some of the small streams which form the headwaters of the James river are southwest of Devils Lake and within a few miles of the source of the Sheyenne. At this place the two rivers are separated by a ridge several miles wide. The country around the western tributaries of this river is much the same as that about the Sheyenne river. The two rivers doubtless joined in the work of draining the early glacial lakes. The James river flows for about 150 miles in a southeasterly direction until it crosses the state line into South Dakota. The general character of the stream and of the surrounding country is much the same as that of the Sheyenne river. The surface to the south is rather more level and of much lower altitude. The channel is cut through clay and drift, but the soil and subsoil have a larger proportion of sand than is found farther north.
Any one who will thoroughly consider the surface appearance presented over nearly all the eastern part of North Dakota will be impressed with the fact that some widely operative and powerful agency, within a comparatively recent geologic period, has been shaping surface features and accumulating, mingling and distributing over large areas the immense amount of unconsolidated foreign material which covers to a considerable thickness earlier stratified formations.
One of the most characteristic deposits within North Dakota is the drift which is spread over a large, part of the state east of the Missouri river. This deposit is made up largely of sand and clay mingled with gravel and boulders, presenting a heterogeneous mass totally unlike the sedimentary formations upon which it lies.
The embedding material is usually thick sheets of blue and yellow clay, sometimes alternating with beds of sand and gravel, in both of which are scattered large blocks of various kinds of rocks, sometimes weighing several thousand pounds. These boulders are frequently smoothed and scored with fine parallel scratches. A knowledge of the character of these rock masses, and a familiarity with some of the rocks outcropping farther north in Canada, leads us to believe that the debris was transported from northern regions. Much of the limestone found in the drift in the northern part of the state was undoubtedly taken from the beds which outcrop about Lake Winnipeg. A study of well excavations and the channels eroded by streams shows that this drift material has covered an old land surface. In some places in the Red River valley, drift and alluvial deposits reach to a depth of 300 to 350 feet. In the northern and western part of the state the thickness is commonly from 30 to 100 feet.
The agent which accomplished this gigantic work must have been a great, slowly moving ice-sheet similar to that which now covers a large part of Greenland. This vast ice-sheet, which in its northern portions, at least, must have been very deep, tore away exposed rock ledges and enveloped and bore along with it the loose material with which it came in contact. This debris was frozen into the ice and, under the enormous weight above it, became a mighty grinding power, and as it moved slowly but irresistibly onward from the north, the enclosed rock masses were worn away to smaller fragments, pebbles, sand and clay, and all mixed with surface clay and soils. Thus was formed, during the long ages of the Glacial period, an enormous amount of this rock refuse, which, with the return of a warmer climate and the melting of the ice-sheet, was intermingled and spread far and wide. This material, by reason of its variety of composition and depth of deposit, is well calculated to become the foundation of the rich soil so characteristic of the eastern and central part of North Dakota.
The drift deposit is sometimes divided into till or boulder clay and stratified drift. The till is naturally lower, and consists of a heterogeneous mass of clay, sand, pebbles, and even large rock masses. The larger rocks are usually more angular than those in the upper stratified material, and frequently show glacial marks. The till is probably derived from the material which was frozen into the lower portion of the ice-sheet and was dropped as the ice melted. No doubt large floating icebergs which had stranded and melted frequently dropped their loads of rock material over a partly stratified drift. In the central part of the state, in the Devils Lake region, the till is found commonly at a depth of fifteen to thirty feet, and usually continues for fifty feet or more. A great number of shallow wells derive their supply of water from this deposit.
The stratified drift is found immediately overlying the till. It is composed usually of fine blue and yellow clay, which in many places is quite free from pebbles or boulders, and shows unmistakable evidence of stratification. This material forms a thick deposit immediately under the soil in the Red River valley, along valleys of several other streams in the eastern part of the state, and over many portions of the Devils Lake drainage basin. The boulders and pebbles which are found in this upper modified drift show clearly, by their smooth and rounded surface, that they have been water-worn. The stratification probably took place after the retreat of the ice-sheet, when the water from the melting ice had formed great lakes which filled the river valleys and lower ground and spread out over large tracts of nearly level land.
The various drift deposits which have just been mentioned indicate that a very large area in North Dakota was at a late geological period covered by a great sheet of ice which stretched far away to the north into Canada. With a change in climatic conditions, the ice began to melt along its southern border, and the water, being banked on the north by the great ice barrier, gradually formed a glacial lake on the southern boundary of the sheet. As the glacier continued its retreat to the north, the extent and depth of the lake increased, the water spreading out over the Red River valley, and, finding no other outlet open, at last overflowed the height of land near Lake Traverse, making its way through that lake and Big Stone Lake into the Minnesota river, and thence into the Mississippi. Finally, however, the ice melted far enough toward the north to open a natural outlet through Lake Winnipeg and Hudson bay, when it began forming the present valley of the Red river. The total area covered by this great lake, known as Lake Agassiz, has been estimated by Warren Upham at 110,000 square miles, over which the water often reached a depth of 500 to 700 feet. The area covered in North Dakota was about 6,000 to 7,000 square miles. After the opening of the northern outlet, Lake Agassiz was rapidly drained. In the low land of the Winnipeg basin, however, a large body of water was left, a portion of which forms the present Lake Winnipeg.
The former presence of this body of water is recorded in three ways — i.e., by lacustrine sediments, by extensive alluvial and delta deposits, and by corresponding extensive erosion. The fine silt and clay which are so characteristic of the Red River valley were undoubtedly deposited from the sediment of Lake Agassiz and the many glacial rivers which brought debris into this basin from the surrounding higher land. The water of the glacial Red river gradually narrowed, but being much deeper in the central portion of the valley, it remained there a longer time, and thus gave opportunity for a thicker deposit of sediment than is found along the old lake margin. Mr. Warren Upham has traced a series of beaches marking clearly the extent of Lake Agassiz at its various stages. The streams which flow through the lacustrine sediments usually have narrow and shallow banks, but the valleys of those streams which flow into the basin of Lake Agassiz are commonly deep and wide, showing much erosion. This is particularly noticeable of the streams flowing from the Little Pembina and Pembina rivers. Along the eastern escarpment of the Pembina mountains the erosive action of the old lake is clearly seen in the almost cliff-like ascent of the Cretaceous tablelands.
But Lake Agassiz was not the only glacial lake by which the surface of the level prairie of North Dakota was modified. In the central part of the state there were probably several lakes at various periods following the glacial epoch, which were formed from the melting of arms of the ice-sheet. One of the most important of these was glacial Lake Souris. Devils Lake and its immediate drainage basin is doubtless a remnant of one of these lakes. The Sheyenne and James rivers were probably started, and high bluffs along the western portion of these streams washed out, during the time when districts to the north, about Devils Lake, and to the west, being flooded by the melting ice, were drained of great quantities of water by these rivers. All through the eastern and central portion of the state, the ice-sheet, the lakes, and the river torrents formed by the melting ice, exerted a powerful influence in giving fertility to the soil and final shape to the surface of our North Dakota prairies.