The sky continued clear, but the wind was high, and the drifting of the sand occasioned much annoyance. The heat of the atmosphere became more intolerable, on account of the showers of burning sand, driven against us with such force as to penetrate every part of our dress, and proving so afflictive to our eyes, that it was with the utmost difficulty we could see to guide our horses. The sand is carried from the bed of the river, which is here a naked beach of more than half a mile wide, and piled in immense drifts along the bank. Some of these heaps we have seen covering all but a small portion of the upper branches of what appeared like large trees. Notwithstanding we were now three hundred miles distant from the sources of the river, we found very little water; and that being stagnant, and so much frequented by bisons and other animals, was so loathsome both to sight and smell, that nothing but the most uncontrollable thirst could have induced us to taste it. At a short distance below the place of our encampment, we passed the confluence of a considerable creek entering from the south-west. Though like all the streams of this thirsty region, its waters were entirely hid in the sand; yet it is evidently the bed of a large tributary, and from its direction, we conclude it can be no other than the one on which the Kaskaias informed us they had encamped the night before we met them. Its name, if it have any, among the Indians or Spaniards, we have not yet learned.[61] We had, for some days, observed a few wild horses, {313} and they, as well as the bisons, were now becoming numerous. In the habits of the wild horse, we find little unlike what is seen in the domestic animal, though he becomes the most timorous and watchful of the inhabitants of the wilderness. They show a similar attachment to each other's society, though the males are occasionally found at a distance from the herds. It would appear, from the paths we have seen, that they sometimes perform long journeys, and it may be worthy of remark, that along these paths are frequently found very large piles of horse-dung, of different ages, affording sufficient evidence that this animal, in a wild state, has, in common with some others, an inclination to drop his excrement where another has done so before him. This propensity is sometimes faintly discovered in the domestic horse. As we were about to halt for dinner, a bison who had lingered near our path was killed; but the flesh was found in too ill a condition to be eaten, as is the case with all the bulls at this season.