[13] The loose soft sands of the river-bed yielding to our horses feet, made the travelling extremely laborious; and the intense reflection of the rays of the sun almost deprived us of the use of our eyes. Mr. Peale's horse soon became unable to proceed at an equal pace with the remainder of the party; but as no suitable place for encampment appeared, he dismounted, and by great exertions was able to urge his animal along in the rear. The travelling in the bed of the river became so extremely inconvenient, that we resolved upon attempting to penetrate the thick woods of the bottom, and ascend to the open plains. We found, however, the woods so thick, and so interlined with scandent species of smilax cissus, and other climbing vines, as greatly to retard our progress, and we were soon induced to wish ourselves again upon the naked sands. Notwithstanding the annoyance they gave us, we took a pleasure in observing the three American species of cissus growing almost side by side. The cissus quinquefolia,[74] the common woodbine, cultivated as an ornament about yards and summer-houses, grows here to an enormous size, and, as well as the cissus hederacea, seems to prefer climbing on elms. The remaining species, the cissus bipinnata, is a smaller plant, and, though much branched, is rarely scandent. All of them abound in ripe fruit, which, notwithstanding its external resemblance and its close affinity to the grape, is nauseous to the taste, and does not appear to be sought with avidity even by the bears. In ascending the hills, we found them based upon a variety of sandstone, unlike the red rock of the salt formation, to which we had been so long accustomed. With this change a corresponding change takes place in the conformation of the surface and the general aspect of the country. The hills are higher and more abrupt, the forests more extensive, the streams of water more copious [14] and more serpentine in their direction; in other words, we here begin to recognize the features of a mountainous region. The sandstone which appears in the beds of the streams, and the sides of the hills, is coarse and hard, of a dark gray colour, and a horizontally laminated structure. It is deeply covered with a soil of considerable fertility, sustaining heavy forests of oak. Among these trees the upland white oak is common, but is of rather diminutive size, and often hollow. In a tree of this description we observed, as we passed, the habitation of a swarm of bees, and as it was not convenient at that time to stop, we fixed a mark upon it, and proceeded to make the best of our way towards the river. On descending the hills, we found the valley of the river much contracted in width, and the bed itself occupying less space by half than where we had left it above.

On the following day the party remained encamped to take observations, and afford an opportunity for rest to the horses. Some of the men went back about six miles to the bee-tree we had passed on the preceding day, and brought in a small quantity of honey enclosed in the skin of a deer recently killed. About our camp we examined several lodges of sandstone, of the coarse dark grey variety above mentioned; in some instances we found it nearly approaching in character the glittering crystalline variety of the lead mines, but we sought in vain for an opportunity to observe the manner of its connexion with red sandstone.

As we were now at the western base of that interesting group of hills, to which we have attempted to give the name of the almost extinct tribe of the Ozarks,[75] and as we believed ourselves near the extreme southern bend of the river we were descending, we thought it important to ascertain our latitude and longitude by as complete sets of observations as was in our power to make; and this the favourable [15] position of the moon enabled us to do in the most satisfactory manner. The results will be seen on the map.

During the extreme heat of the day the mercury stood at 99° in a fair exposure. This extraordinary degree of heat may have been in some degree connected with the stagnation of the air between the hills, and possibly with the reverberation of the sun's rays from the naked sands; but the instrument was one of an approved character, and was exposed in the deep shade of an extensive grove of trees.

As yet no running water appeared in the river; but as the pools were large, and some of them little frequented by the bisons, we were no longer under the necessity of digging.

September 1st. The sycamore, the æsculus, the mistletoe, and the paroquet,[76] are conspicuous objects in the deep and heavy forests of the Ohio and Mississippi; with these we now found ourselves surrounded. Bisons were comparatively scarce along this part of the river, but whether this was owing to the near approach of inhabited countries, or to the great extent and almost impenetrable density of the forests on each side of the river, we were unable to determine; at night we still heard the growling of the herds in the distant prairies, and occasionally saw bisons in small bodies crossing the river.

The Kaskaia Indians had told us, that before we arrived at the village of the Pawnee Piquas, we should pass a range of blue hills. These we concluded could be no other than hills whose sides were covered with forests, like those we were now passing, and accordingly we watched with some anxiety for the appearance of something which should indicate the vicinity of an Indian village. As we pursued our way along the serpentine bed of the river, the valley became narrower, the hills more elevated, and as we crossed the rocky points of their bases, we could not [16] but observe that the sandstone was of a different character from any we had before seen. It contains more mica than that of the Alleghanies, or that of the secondary hills along the base of the Rocky Mountains; it glitters conspicuously, like mica-slate when seen in the sunshine; and this, as we found by examination, does not depend entirely on the great proportion of mica it contains, but also in some degree upon the crystalline surfaces of the minute particles. Its cement is often argillaceous, and this, as well as the impressions of some organic relics[77] we observed in it, induced us to expect the occurrence of coal-beds.

On ascending the hills from the place of our midday encampment, we found this sandstone at an elevation of about two hundred feet (according to our estimate) from the bed of the river, succeeded by a stratum of limestone of the common compact blue variety, abounding in casts of anomias, entrochi, &c. This rests horizontally upon the summits of the hills, and disintegrating less rapidly than the sandstone which forms their bases, it is sometimes left projecting in such a manner as to render access impossible. Climbing to the summit of some of the hills near the river, we had the view towards the south and east of a wild and mountainous region, covered with forests, where, among the brighter verdure of the oak, the nyssa, and the castanea pumila, we distinguished the darker shade of the juniper, and others of the coniferæ.

A little before arriving at the place of our evening encampment, we observed the track of a man who had passed on foot, and with bare feet, down the river. This we were confident could be no other than the track of our lost interpreter Adams. What accident could have deprived him of his mule we [17] were at a loss to conjecture. We found it equally difficult to account for his pushing forward with such perseverance, when he must have had every reason to believe we were behind him.