The occurrence of the elm, the phytolacca, the cephalanthus, and other plants not to be met with in a desert of sand, give us the pleasing assurance of a change we have long been expecting to see in the aspect of the country. The blue jay, the purple martin, a deer, and some turkeys, were also seen near this encampment.
The bed of the river is here eight hundred yards wide, but the quantity of water visible is much less than in some places above. The magnetic variation ascertained at this camp was 12° 30′ east.
[309] CHAPTER VI [XIII]
Sand Plains—Mississippi Hawk—Small-leaved Elm—Wild Horses—Hail-storm—Climate—Bisons—Grapes—Red Sand Formation—Gypsum.
August 15th. Extensive tracts of loose sand, so destitute of plants, and so fine as to be driven with the wind, occur in every part of the saline sandstone formation we had as yet seen. They are perhaps invariably the detritus of the sand-rock, deposited in valleys and depressions, where the rapidity of the abrading currents has been checked by permanent obstacles. This loose sand differs in colour from the sandstone, which is almost invariably red; the difference may, however, have been produced simply by the operation of water suspending and removing the light colouring matter, no longer retained by the aggregation of the sandstone. These fields of sand have most frequently an undulating surface, occasioned probably not less by the operation of winds than by the currents of water; a few plum bushes, almost the only woody plants found on them, wherever they take root, form points, about which the sand accumulates, and in this manner permanent elevations are produced. The yucca angustifolia and the shrubby cactus are here rarely seen; the argemone and the night-flowering bartonia have not entirely disappeared, but are not of frequent occurrence.
Our horses had broken loose, and a part of them strayed from camp. This occasioned some unusual delay, and the morning was somewhat advanced when we commenced our ride. The day was bright and cool, comparatively so at least, the mercury in [310] the extreme heat rising to only 95° in the shade of our tent, whereas on several of the preceding days, it had stood at or above 100° in a fairer exposure. A light breeze sprung up from the south-west, and continued during the remainder of the day. Our course led us twice across the bed of the river, which we found one thousand and four hundred paces in width; and without water, except in a few small pools, where it was stagnant. This wide and shallow bed is included between low banks, sometimes sloped gradually, and sometimes, though rarely, perpendicular, and rising scarcely more than four feet from the common level of the bottom of the channel. Drift wood is occasionally seen without these banks, affording evidence that they are at times not only full, but overflowed. If they are ever but partially filled, it is easy to see that what, for a great part of the year, is a naked sand beach, then becomes a broad and majestic river. It must flow with a rapid current, and in floods; its waters cannot be otherwise than of an intense red colour. The immediate valley of the river had now become little less than two miles in width; and had, in some places, a fertile soil. This happens wherever there occur spots having little elevation above the bed of the river, and which have not recently been covered with sand.
Several species of locust were extremely frequent here, filling the air by day with their shrill and deafening cries, and feeding with their bodies great numbers of that beautiful species of hawk, the falco Mississipiensis of Wilson.[59] It afforded us a constant amusement to watch the motions of this greedy devourer in the pursuit of his favourite prey, the locust. The insect being large, and not uncommonly active, is easily taken; the hawk then pauses on the wing, suspending himself in the air, while, with his talons and beak, he tears in pieces and devours his prey.
We were also fortunate in capturing a tortoise, [311] resembling the T. geographica of Le Sueur.[60] The upper part of its shell was large enough to contain near a quart of water, and was taken to supply the place of one of our tin cups recently lost, while the animal itself was committed to the mess kettle. Wolves, jackals, and vultures, occurred in unusual numbers, and the carcasses of several bisons recently killed had been seen. We could also distinguish the recent marks of a hunting party of Indians, the tracks of horses and of men being still fresh in the sand. At four P. M., several bisons were discovered at a distance, and as we were in the greatest want of provisions, we halted, and sent the hunters in pursuit; and being soon apprized of their success, the requisite preparations were made for jerking the meat. Near our camp was a scattering grove of small-leaved elms. This tree (the U. alata, N.) is not known in the Eastern states; but it is common in many parts of Tennessee, Missouri, and Arkansa. When found in forests intermixed with other trees, it is usually of a smaller size than the ulmus americana, and is distinguished from it by the smallness of the leaves and the whiteness of the trunk. On the borders of the open country, where large trees often occur entirely isolated, the ulmus alata has proportionally a more dense and flattened top than any other tree we have seen. When standing entirely alone, it rarely attains an elevation of more than thirty or thirty-five feet; but its top lying close to the ground, is spread over an area of sixty or seventy feet in diameter, and is externally so close and smooth as to resemble, when seen from a distance, a small grassy hillock.