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. Near our camp was a circular breast-work, constructed like those already mentioned, and large enough to contain eighty or an hundred men. We were not particularly pleased at meeting these works so frequently as we had done of late, as they indicate the country where they are found, to be one {312} particularly exposed to the depredations of Indian war-parties. August 16. The greater part of the flesh of the bison killed on the preceding evening had been dried and smoked in the course of the night, so that we had now no fear of suffering immediately from hunger, having as much jerked meat as was sufficient to last several days.