Popular Science Monthly/Volume 24/April 1884/Correspondence
IT is a fact well known to all who have made any study of the "Bottom," or alluvial plain, formed during the lapse of ages by the great Mississippi River, that the river channel, or bed, is forever shifting, and in its mighty contortions it has moved laterally eastward and westward over vast spaces. Many of the abandoned channels are now curved lakes, with no connection with the river; others, connected with it more or less during floods, are called "old rivers." So thoroughly the river does its work in forming the land that, besides these crescent-shaped lakes and old rivers, there is little in view to indicate where the bed of the river lay one hundred or one thousand years ago. When the river changes its channel, by suddenly or gradually cutting through a point of land, or when one chute of an island is closed by a bar, a lake or an old river is formed; but, when the river shifts its position, by continued abrasion on one side, and by corresponding deposit of sediment on the other, the latter slowly but steadily rises to the average height of the neighboring land, and in a few years is covered by a heavy forest-growth, and there is no visible sign left to show that it has not been thus since the creation, or at least since the Gulf of Mexico deserted that particular point on its ever-lasting retreat southward.
The tract of land on which I reside, and which I have owned for more than forty years, was washed, up to about the year 1855, by the main body of the Mississippi River, swinging around the western side of a plano-convex-shaped island; at that period three fourths of all the water of the river passed my door, but about that time, the exact year I do not remember, the channel began to change, and in a very few years the main body of water was, and has since then been, running down the piano and eastward side of the island, and the head of the western chute is largely obstructed by bars. Whether the bars formed first, and forced the channel eastward, or whether the change of the channel caused the bars to form, has not, so far as I know, been satisfactorily answered. At all events, my land now lies on an "old river," which is never entirely dry, although often very nearly so, and the growing obstructions threaten to cut me off, at no distant day, from outside communication, at least by water, except at very high stages. I will add, in passing, that it is in contemplation by the National River Improvement Commission (which is spending millions in the interest of navigation, with no especial thought as to riparian interests) to hurry up this consummation by piling, willow-mattressing, etc., so as to force the entire body of water, even in its highest stages, through the eastern or shorter chute.
In addition to being located on an "old river," my land lies, as I believe, just where a river-formed lake existed at a remote period, but which has in process of time, long before memory goes, been filled up by deposits from overflows, until now it is some-what higher than the general level of the neighboring sections, and I will give my reasons for so thinking as briefly as I can. At certain periods of the year, as there are no small running streams in this section, cattle suffer from thirst, although the great river runs by our doors, for then the stream is low, and the banks are either precipitous, or, when sloping, terminate in a quicksand, in which many uncared-for cattle are lost every year; hence the necessity for abundant wells and cisterns.
Seeing some water standing in an old, hollow cypress-stump, about four fee tin diameter, the surface of which water was at least fifteen feet above the surface of the river at the time, I was curious enough to investigate the matter. An outside rim of the stump, about four inches in thickness, remained sound, but the interior portion (all except a hollow of about a foot in diameter, down which I had observed the water) was composed of dry-rotted wood, still clinging closely in place. I had the rotted portion taken out down to the surface of the water, and the water pumped out, finding the reservoir to extend down sixteen feet. In about six hours the water had returned to its former level. Pumping it out again, I had the rotten wood removed; this was done with very little trouble. With a little more digging, and removing the old wood, which had previously fallen to the bottom, I discovered where the main roots of the tree started at a distance of about seventeen feet below the surface of the ground, plainly showing that, when the tree first sprang from the seed, the surface of the ground was many feet lower than at present. After thoroughly cleaning out the well, I permitted the water again to rise, and found it cool and wholesome, with a slightly brackish taste, but not at all offensive.
Subsequent investigation showed me that every hollow cypress-stump (and there are a large number of them) on my place is a natural well, but varying in depth, proving that the ground on which these trees sprouted was not level, or at least that the level was changed from time to time. I have one of these wells in my stable-yard; it is about four feet in diameter and nine feet in depth. I cut the stump off level with the ground, floored it over, and placed a pump in it, and in the driest seasons it furnishes abundant water for my stock. I have about fifteen dug wells on my place, all within the space of two square miles; the depth of the water-surface in these varies from eight to fifteen feet. A large curbed well stands in my gin-house, within twenty feet of the bank of the river, and to-day the water stands in this well at least fifteen above the surface of the stream, and is in no manner affected by its rise or fall. It would not be difficult to form a reasonable theory to account for the deeply-rooted cypresses, but the formation and existence of the wells require the presumption of an enormous deposit of clay, and to account for the presence of the latter is the difficulty. The Mississippi brings down in suspension a comparatively small portion of argillaceous material, but it is certainly here in a solid stratum, and it came at a period subsequent to the sprouting of the old cypress-trees, for it is highly improbable that a tree should send down a tap-root eighteen feet, and then spread out its lateral supports. The cypresses, forty years old, make no such indications, but have their radical processes corresponding with those of the other trees of the forest.
|James B. Craighead.|
|Nodena, Arkansas, August 1, 1883.|
In the February number of your magazine appears an article, by Arthur F. Astley, on the "Working Capacity of Unshod Horses," in which the writer states, "In New Mexico, horses are ridden barefoot forty miles day after day, and perhaps twenty miles of this will be over a rough mountain-track." Now, I have served with my regiment in New Mexico for several years, most of the time as post-quartermaster, having large numbers of both horses and mules under my charge. While it is true that most horses are ridden unshod by the natives in the valleys, where the roads are sandy and soft, it should be borne in mind that even there the majority do so simply because they are too poor to have their horses shod; but, when it comes to traveling over rough mountain-tracks, the writer's statement is simply absurd. The Indians (Apaches) understand the inability of unshod horses to travel over mountain-trails so well, that they cover their horses' feet with raw-hide bags, and, when the latter wear out, the horses soon become disabled, and I have frequently found Indian horses abandoned on the trail, with their hoofs bleeding and worn, and the poor animals in a most pitiful plight. Again, when Indians are enlisted as scouts, they furnish their own mount, and, when reaching the post, they always request to have their horses shod. There can be no question that a properly-shod horse has a superior working capacity, but I confess that most shoeing, from the ignorance of the average farrier, is simply a process of torture and violation of nature, and crippled horses are the result. Most farriers place the horse upon an iron tripod, the weight of the animal resting entirely upon three points of the foot, and those not the parts intended to bear the shock of travel, or to sustain his weight. The position of the frog becomes one of hopeless inaction, and the motion of the unsupported bones within the hoof produces inflammation at the points of extreme pressure. But I did not intend to write an essay on horse-shoeing.
|Lieutenant, United States Army.|
|Washington, D. C., February 17, 1884.|
I have just read Mr. D. W. Williams's interesting article in your December issue on "The Loess-Deposits of Northern China," and am rather surprised to find no allusion therein, by way of comparison or otherwise, to the very extensive loess-deposits of the United States—especially, since it was here, in the valley of the Mississippi, that this peculiar soil was first studied and named loess by Sir Charles Lyell, during his second visit to the United States in 1846.
Mr. Williams speaks of the loess-beds of China as among the most remarkable and important geological phenomena hitherto brought to light in Middle Asia, and says "the term loess has been used to designate a tertiary deposit appearing in the Rhine Valley, along the Danube, and in several isolated sections of Europe," etc. But the loess-beds of Nebraska, alone, exceed in extent of area those of all Europe combined; and their aggregate extent within the States of Nebraska and Minnesota and the Territory of Dakota falls but little, if any, below that of the loess-beds proper of Northern China. It is believed that the total extent in square miles of this deposit within the States and Territories drained by the Missouri and Mississippi Rivers exceeds that within the Chinese provinces drained by the Yellow, the Wei, and the northern tributaries of the Tangtse.
Mr. Williams does not give any analyses of the Chinese loess, but it appears to be not essentially unlike that of the Rhine, which, as analyzed by Bischoff, contains a larger proportion of alumina than the samples hitherto analyzed from Nebraska. Bischoff found in four analyses of Rhine loess:
|NUMBER OF ANALYSIS|
|Peroxide of iron||4.25||4.81||5.14|
|Lime||0·02||0·02||. . . .||. . . .|
|Carbonate of lime.||20·16||. . . .||. . . .||11·63|
|Carbonate of magnesia||4·21||. . . .||. . . .||8·02|
|Loss by ignition||1·37||. . . .||1·89||2·31|
Dr. Hayden, in his "Final Report on the Geology of Nebraska," gives, on page 12, two analyses of the loess from Hannibal, Missouri, made by Dr. Lytton, as follows: in one hundred parts, there were of—
|No. 1.||No. 2.|
|Alumina and peroxide of iron||11·54||12·10|
Dr. Aughey, in his Report on the Superficial Deposits of Nebraska" (United States Geological Survey, 1874), gives the analyses of five samples of the Nebraska loess taken from widely-separated sections, showing the wonderful homogeneity of the deposit over the large area which it covers in that State—estimated at not less than fifty-eight thousand square miles. His analyses are as follows:
|No. 1.||No. 2.||No. 3.||No. 4.||No. 5.|
|Insoluble (siliceous) matter||81·82||81·83||81·35||81·30||81·32|
|Loss in analysis||·59||·54||·53||·55||·47|
It will be seen from these several analyses that the loess of the Rhine and that of the Republican and the upper and lower Missouri are not chemically dissimilar. The latter is thoroughly homogeneous and of uniform color from whatever depth taken.
Dr. Aughey says: "I have compared many specimens taken three hundred miles apart, and from the top and bottom of the deposits, and no difference could be detected by the eye, or by chemical analysis. Over eighty per cent of this deposit is finely-comminuted silica. ... So fine, indeed, are the particles of silica that its true character can alone be detected by analysis or under the microscope." The tendency, noted by Mr. Williams, in the Chinese loess to crystallize spontaneously, and form the cylindrical and spherical concretions which the Chinese call "ginger-stones," is also noticeable over all the loess-regions of the West. Wherever the sod is broken or the earth freshly disturbed from any cause, whether by the plow, or "prairie-dogs," these "ginger-stones" literally cover the ground. This feature is presumably due to the richness of the soil in the phosphates and carbonates of lime, which constitute about one tenth of the entire mass.
In their structural as well as chemical characteristics our Western loess-beds seem to be identical with those of China. They present, also, the same striking peculiarities of landscape-contour, erosion-products, and surpassing fertility, so well described by Mr. Williams. The unique and often exceedingly fantastic forms assumed by the loess-bluffs wherever they have been subject to erosion, as along the Missouri and lower Platte, have long excited the curiosity of tourists. Indeed, so quaint and striking are many of these natural carvings—now stately and now grotesque—that it is not easy on first acquaintance to accept them as the products of natural causes merely, and not rather as the gigantic labors of past generations. In point of architectural adaptability, too, these Nebraska bluffs are the fellows of their Chinese congeners, and fulfill the same generous function of affording cheap and healthful domiciles to whomsoever will carve out their homes in them. Many are the happy and well-to do families, scattered over these fertile regions—especially in Nebraska, Dakota, and Southwestern Minnesota—who have known no other home since "coming West" than the smoothly-hewed walls of the facile loess. Nor, for ends of comfort, cleanliness, or health, do they need to seek better homes only at the behest of taste or fashion; though, as wealth increases, the American squatter, unlike the Mongolian, soon builds for himself a more pretentious dwelling, and converts his old home into a stable or piggery. I have sometimes had occasion to seek shelter from a storm in one of these "dug-outs," and in traveling have often spent a night in them, and can testify as to the excellent quarters they afford for both man and beast. Like the "adobe" houses of the Mexicans and Pueblo Indians, they are cool in summer and warm in winter, but are superior to "adobe" dwellings in point of dryness and cleanliness. This superiority is due to the fact that wherever the soil is smoothly cut the slight chemical union, which speedily takes place under the influence of the atmosphere between the silica and the carbonate of lime, coats the surface as if with a light washing of cement, and so prevents crumbling. One may note spade-marks as clean-cut and fresh-looking as if newly made on the walls or ceiling of "dugouts" that have been occupied for years. When the threatened (?) "Mongolian invasion" comes, what hosts of happy Celestials will find here congenial homes! And if, for their better contentment, they rechristen the Missouri the Yellow River, it will be no serious misnomer.
In point of fertility our Western loess-beds are the counterpart of those described by Mr. Williams, except that they do not seem to suffer equally in seasons of drought. The greater depth of the Nebraska deposits—exceeding in many places two hundred feet—and, possibly, their more perfect capillary structure, may explain this difference.
As to the origin of the loess-beds of the United States, the belief of Drs.. Hayden, Aughey, and others that they are lacustrine deposits has been hitherto accepted. But it is curious to note how many of their peculiar characteristics are explained, and their general features harmonized with the geological and meteorological phenomena of the great region lying between them and the summit of the Rocky Mountains, by the hypothesis that they are subaërial rather than subaqueous deposits. Nearly all the arguments adduced by Baron von Richthofen in support of his theory of the origin of the loess-beds of Asia may be adduced with equal force, mutatis mutandis, in support of a like theory here. Of more than one hundred and twenty species of shells found and identified in the loess-deposits of Nebraska, as given by Dr. Aughey on pages 267 and 268 of "United States Geological Report" for 1874, it will be seen that a large proportion are land-shells. And it appears from the same "Report" that, while the deposits are rich in the remains of land-animals, no considerable number of aquatic species have ever been identified.
Dr. Aughey says, page 254: "Occasionally I have found the teeth and a stray bone of a fish, but have not been able to identify any species. The remains of rabbits, gophers, otters, beavers, squirrels, deer, elk, and buffalo are frequently found. Through the entire extent of these deposits are many remains of mastodons and elephants." To one who has ever encountered a dust-storm on the great plains west of these deposits, when the landscape to either horizon is obscured with flying clouds of powdery dust, like drifting fog, and has noted the almost continuous belt of sand-hills extending from Western Kansas through Eastern Colorado and Wyoming and Western Nebraska, evidently formed by these high winds, whose prevailing direction is always eastward, and marking the deposit of the heavier particles dropped from the flying mass of dust-freight which they had gathered in their fury from the arid foot-hills and high plains still farther westward, the theory of Von Richthofen commends itself with peculiar force. And if a period of still greater aridity be conceived of, before these high regions, the American analogues of the Asiatic steppes, had received their present scant protection of stunted grasses, the conviction arises that, even assuming the volume and velocity of the wind to have been no greater then than now, its prevailing direction being the same, our loess-deposits of the North-west, like those of China, may be accounted for, both as to their origin and chief peculiarities, by reference to known causes still existing, whose action has been, indeed, greatly modified but not wholly suspended; and without recourse, necessarily, to the lacustrine hypothesis.
|William T. Holt.|
|Denver, Colorado, January 4, 1884.|