Tributaries of the Canadian cotton wood
The region we were now traversing is one of great fertility, and we had daily occasion to regret that our visit to it had not been made earlier in the season. Many unknown plants were observed, but their flowering season having passed, the fruit of many of them had ripened and fallen. We were deprived of the means of ascertaining the name and place of such as had been heretofore described, and of describing such as were new. We had, however, the satisfaction to recognize some interesting productions, among which we may enumerate a very beautiful species of bignonia, and the bow-wood or osage orange. The rocky hills abound in trees of a small size, and the cedars are sometimes so numerous, as to give their peculiar and gloomy colouring to the landscape. We listened as we rode forward to the note of a bird, new to some of us, and bearing a singular resemblance to the noise of a child's toy trumpet; this we soon found to be the cry of the great ivory-billed wood-pecker (picus principalis), the largest of the North American species, and confined to the warmer parts. The picus pileatus we had seen on the 25th of August, more than one hundred miles above, and this with the picus erythrocephalus were now common. Turkies were very numerous. The paroquet, chuck-wills-widow, wood-robin, mocking bird, and many other small birds, filled the woods with life and music. The bald eagle, the turkey buzzard, and black vulture, raven and crow, were seen swarming like the blowing flies about any spot where a bison, an elk, or a deer had fallen a prey to the hunter. About the river were large flocks of pelicans, with numbers of snowy herons, and the beautiful ardea egretta.
Soon after we had commenced our morning ride, we heard the report of a gun at the distance of a mile, as we thought, on our left; this was distinctly heard by several of the party, and induced us to believe that white hunters were in the neighbourhood. We had recently seen great numbers of elk, and killed one or two, which we had found in bad condition.
September 6th. Numerous ridges of rocky hills traverse the country from north-east to south-west, crossing the direction of the river obliquely. They are of a sandstone, which bears sufficient evidence of belonging to a coal formation. At the spot where we halted to dine, one of these ranges, crossing the river, produces an inconsiderable fall. As the whole width of the channel is paved with a compact horizontal sandstone, we believed all the water of the river must be forced into view, and were a little surprised to find the quantity something less than it had been almost six hundred miles above in the same stream. It would appear, that all the water which falls in rains or flows from springs in an extent of country larger than Pennsylvania, is not sufficient to supply the evaporation of so extensive a surface of naked and heated sands.
The paroquet, chuck-wills-widow, wood-robin, mocking bird, and many other small birds, filled the woods with life and music.
If the river of which we speak should at any season of the year contain water enough for the purposes of navigation, it is probable the fall occasioned by the rocky traverse above mentioned will be sufficient to prevent the passage upwards. The point is a remarkable one, as being the locality of a rare and beautiful variety of sandstone. The rock which appears in the bed of the river is a compact slaty  sandstone, of a deep green colour, resembling some varieties of chloritic slate.
Excerpt from: Early Western Travels 1748-1846 by Various