At eight o'clock on the morning of the 12th of August we took our leave of the Kaskaias, having recovered from them all the articles they had stolen, except a few ropes, halters, and other small affairs, which not being indispensably necessary to us, we chose to relinquish, rather than submit to a longer delay among a people we had so much reason to dislike. They had shown a disposition so far from friendly towards us, that we were surprised to have escaped without having found it necessary to use our rifles among them; and as we thought it by no means improbable some of their young men might follow us to steal our horses, we moved on rather briskly, intending to travel as far in the course of the day as we conveniently could. The river valley spread considerably a little below the point where we had encamped. In many places we found the surface a smooth and naked bed of {303} sand; in others, covered by an incrustation of salt, like a thin ice, and manifestly derived from the evaporation of water which had flowed down from the red sandstone hills bounding the valley. These hills were here of moderate elevation, the side towards the river being usually abrupt and naked. The sandstone is fine, of a deep red colour, indistinctly stratified and traversed in various directions by veins filled principally with sulphate of lime. We had seen among the Indians on the preceding day quantities of salt in large but detached crystalline fragments, greatly resembling the common coarse salt of commerce. It had evidently been collected from some place like the one above mentioned, where it had been deposited from solution in water. When we inquired the particular locality of the Indians, they pointed to the south, and said it was found near the sources of a river heading in that direction. At the place of our evening encampment, we saw the red-necked avoset (recurvirostra americana), the minute tern (sterna minuta), and several other strand birds which we could not approach near enough to distinguish the species. There is also a very evident similarity between the plants found here and many of those growing in saline soils along the sea coast. We saw here several species of atriplex, chenopodium, salsola, kochia, and anabasis, all delighting in a saline soil, and affording on analysis a greater proportion of soda than most inland plants. The day had been unusually warm. During all our mid-day halt, protracted, on account of the sultriness of the weather, to an unusual length, the mercury had remained at 100°, the thermometer being suspended in the closest shade we could find. It is to be remarked, however, that in almost every one of the numerous instances when the mercurial column had indicated so high a temperature as in {304} the one just mentioned, a fair exposure could not be had.