Of the first, which he calls the 'Salt Plain,' he remarks, that "the approach was very gratifying, and from the appearance one might expect to find salt in a solid mass, for the whole extent of the plain, of several feet in thickness." This is situated in the forks of the Salt Fork of the Arkansas. The plain is described as being level as a floor, and evidently sometimes overflowed by the streams which border it. Yet the extent of salt, it would seem, did not realize Capt. Boone's anticipations, as he remarks that it was covered "with the slightest possible film of crystallized salt on the surface, enough to make it white." But he explored only a small portion of the plain, which was very extensive. [p245]
However, the most wonderful saline is the great Salt Rock, which he found further to the {188} southwestward, on the main Red Fork. "The whole cove on the right of the two forks of the river," says Capt. Boone, "appears to be one immense salt spring of water so much concentrated, that, as soon as it reaches the point of breaking forth, it begins depositing its salt. In this way a large crust, or rock is formed all over the bottom for perhaps 160 acres. Digging through the sand for a few inches anywhere in this space, we could find the solid salt, so hard that there was no means in our power of getting up a block of it. We broke our mattock in the attempt. In many places, through this rock-salt crust the water boiled up as clear as crystal ... but so salt that our hands, after being immersed in it and suffered to dry, became as white as snow. Thrusting the arm down into these holes, they appeared to be walled with salt as far down as one could reach. The cliffs which overhang this place are composed of red clay and gypsum, and capped with a stratum of the latter.... We found this salt a little bitter from the impurities it contained, probably Epsom salts principally." As it is overhung with sulphate of lime, and perhaps also based upon the same, might not this 'salt-rock' be heavily impregnated with this mineral, occasioning its excessive hardness? Capt. Boone also speaks of gypsum in various other places, both north and south of this, during his travel.
Mr. Sibley (then of Fort Osage), who was quite familiar with the western prairies, visited {189} a saline, over thirty years ago, which would seem to be the 'Salt Plain' first mentioned by Capt. Boone. The former, it is true, found the salt much more abundant than as described by the latter; but this may be owing to Capt. Boone's not having [p246] penetrated as far as the point alluded to by Mr. Sibley,—whose description is in the following language:[153]
"The Grand Saline is situated about 280 miles southwest of Fort Osage, between two forks of a small branch of the Arkansas, one of which washes its southern extremity, and the other, the principal one, runs nearly parallel, within a mile of its opposite side. It is a hard level plain of reddish colored sand, and of an irregular or mixed figure. Its greatest length is from northwest to southeast, and its circumference about thirty miles. From the appearance of the driftwood that is scattered over, it would seem the whole plain is at times inundated by the overflowing of the streams that pass near it. This plain is entirely covered in dry hot weather, from two to six inches deep, with a crust of beautiful clean white salt, of a quality rather superior to the imported blown salt. It bears a striking resemblance to a field of brilliant snow after a rain, with a light crust on its top."
This is, in extent and appearance, nearly as described by several hunters and Indian traders with whom I have conversed. Col. Logan, a worthy former agent of the Creek Indians,[154] {190} visited no doubt the same, not far from the same period; and he describes it in a similar manner—only representing the depth of the salt as greater. Everywhere that he dug through the stratum of earth about the margin, at the depth of a few inches he came to a rock of solid salt, which induced him to believe that the whole country thereabouts was based upon a stratum of 'rock salt.' [p247] This was of a reddish cast, partaking of the color of the surface of the surrounding country. Mr. Sibley remarks that "the distance to a navigable branch of Arkansas is about eighty miles"—referring perhaps to the Red Fork; though the saline is no doubt at a still less distance from the main stream.
With such inexhaustible mines of salt within two or three days' journey of the Arkansas river, and again within the same distance of the Missouri, which would cost no further labor than the digging it up and the transporting of it to boats for freighting it down those streams, it seems strange that they should lie idle, while we are receiving much of our supplies of this indispensable commodity from abroad.
Besides the salines already mentioned, there is one high on the Canadian river, some two hundred miles east of Santa Fé. Also, it is said, there are some to be found on the waters of Red River; and numerous others are no doubt scattered throughout the same regions, which have never been discovered.
Many of the low valleys of all the western {191} streams (Red River as well as Arkansas and its branches), are impregnated with salinous qualities, and, during wet weather, ooze saltish exudations, which effloresce in a thin scum. This is sometimes pure salt, but more frequently compounded of different salts—not only of the muriate, but of the sulphate of soda, and perhaps magnesia; often strongly tinctured with nitre. Some of the waters of these sections (particularly when stagnant) are so saturated with this compound during dry weather, that they are insupportable even for brutes—much to the consternation of a forlorn traveller. In these saline flats nothing grows but hard wiry grass, which a famished beast will scarcely eat. [p248]
It is from these exudations, as well as from the salines or salt plains before mentioned, that our western waters, especially from Arkansas to Red River, acquire their brackishness during the low seasons; and not from the mountains, as some have presumed. Such as issue from thence are there as pure, fresh and crystalline as snow-fed rills and icy fountains can make them.
It will now readily be inferred that the Great Prairies from Red River to the western sources of the Missouri, are, as has before been intimated, chiefly uninhabitable—not so much for want of wood (though the plains are altogether naked), as of soil and of water; for though some of the plains appear of sufficiently fertile soil, they are mostly of a sterile character, and all too dry to be cultivated. {192} These great steppes seem only fitted for the haunts of the mustang, the buffalo, the antelope, and their migratory lord, the prairie Indian. Unless with the progressive influence of time, some favorable mutation should be wrought in nature's operations, to revive the plains and upland prairies, the occasional fertile valleys are too isolated and remote to become the abodes of civilized man.