The carts having been discharged, the covers and wheels were taken off, and, with the frames, carried into some low places, among the willows, and concealed in the dense foliage in such a manner that the glitter of the iron-work might not attract the observation of some straggling Indian. In the sand, which had been blown up into waves among the willows, a large hole was then dug, ten feet square and six feet deep. In the mean time, all our effects had been spread out upon the ground, and whatever was designed to be carried along with us separated and laid aside, and the remaining part carried to the hole and carefully covered up. As much as possible, all traces of our proceedings were obliterated, and it wanted but a rain to render our cache safe beyond discovery. All the men were now set at work to arrange the pack-saddles and make up the packs.
The day was very warm and calm, and the sky entirely clear, except where, as usual along the summits of the mountainous ridge opposite, the clouds had congregated in masses. Our lodge had been planted, and, on account of the heat, the ground-pins had been taken out, and the lower part slightly raised. Near to it was standing the barometer, which swung in a tripod frame; and within the lodge, where a small fire had been built, Mr. Preuss was occupied in observing temperature of boiling water. At this instant, and without any warning until it was within fifty yards, a violent gust of wind dashed down the lodge, burying under it Mr. Preuss and about a dozen men, who had attempted to keep it from being carried away. I succeeded in saving the barometer, which the lodge was carrying off with itself, but the thermometer was broken. We had no others of a high graduation, none of those which remained going higher than 135° Fahrenheit. Our astronomical observations gave to this place, which we named Cache camp, a longitude of 106° 38' 26", latitude 42° 50' 53".
29th.--All our arrangements having been completed, we left the encampment at 7 o'clock this morning. In this vicinity the ordinary road leaves the Platte, and crosses over to the Sweet Water river, which it strikes near Rock Independence. Instead of following this road, I had determined to keep the immediate valley of the Platte so far as the mouth of the Sweet Water, in the expectation of finding better grass. To this I was further prompted by the nature of my instructions. To Mr. Carson was assigned the office of guide, as we had now reached a part of the country with which, or a great part of which, long residence had made him familiar. In a few miles we reached the Red Buttes, a famous landmark in this country, whose geological composition is red sandstone, limestone, and calcareous sandstone and pudding-stone.
The river here cuts its way through a ridge; on the eastern side of it are the lofty escarpments of red argillaceous sandstone, which are called the Red Buttes. In this passage the stream is not much compressed or pent up, there being a bank of considerable though variable breadth on either side. Immediately on entering, we discovered a band of buffalo. The hunters failed to kill any of them; the leading hunter being thrown into a ravine, which occasioned some delay, and in the mean time the herd clambered up the steep face of the ridge. It is sometimes wonderful to see these apparently clumsy animals make their way up and down the most broken precipices. We halted to noon before we had cleared this passage, at a spot twelve miles distant from Cache camp, where we found an abundance of grass. So far, the account of the Indians was found to be false. On the banks were willow and cherry trees. The cherries were not yet ripe, but in the thickets were numerous fresh tracks of the grizzly bear, which are very fond of this fruit. The soil here is red, the composition being derived from the red sandstone. About seven miles brought us through the ridge, in which the course of the river is north and south. Here the valley opens out broadly, and high walls of the red formation present themselves among the hills to the east. We crossed here a pretty little creek, an affluent of the right bank. It is well timbered with cottonwood in this vicinity, and the absinthe has lost its shrub-like character, and becomes small trees six and eight feet in height, and sometimes eight inches in diameter. Two or three miles above this creek we made our encampment, having traveled to-day twenty-five miles. Our animals fared well here, as there is an abundance of grass. The river bed is made up of pebbles, and in the bank, at the level of the water, is a conglomerate of coarse pebbles, about the size of ostrich eggs, and which I remarked in the banks of the Laramie fork. It is overlaid by a soil of mixed clay and sand, six feet thick. By astronomical observations, our position is in longitude 106° 54' 32", and latitude 42° 38'.
30th.--After traveling about twelve miles this morning, we reached a place where the Indian village had crossed the river. Here were the poles of discarded lodges and skeletons of horses lying about. Mr. Carson, who had never been higher up than this point on the river, which has the character of being exceedingly rugged, and walled in by precipices above, thought it advisable to encamp near this place, where we were certain of obtaining grass, and to-morrow make our crossing among the rugged hills to the Sweet Water river. Accordingly we turned back and descended the river to an island near by, which was about twenty acres in size, covered with a luxuriant growth of grass. The formation here I found highly interesting. Immediately at this island the river is again shut up in the rugged hills, which come down to it from the main ridge in a succession of spurs three or four hundred feet high, and alternated with green level prairillons or meadows, bordered on the river banks with thickets of willow, and having many plants to interest the traveler. The island lies between two of these ridges, three or four hundred yards apart, of which that on the right bank is composed entirely of red argillaceous sandstone, with thin layers of fibrous gypsum. On the left bank, the ridge is composed entirely of silicious pudding-stone, the pebbles in the numerous strata increasing in size from the top to the bottom, where they are as large as a man's head. So far as I was able to determine, these strata incline to the northeast, with a dip of about 15°. This pudding- stone, or conglomerate formation, I was enabled to trace through an extended range of country, from a few miles east of the meridian of Fort Laramie to where I found it superposed on the granite of the Rocky mountains, in longitude 109° 00'. From its appearance, the main chain of the Laramie mountain is composed of this rock; and in a number of places I found isolated hills, which served to mark a former level which had been probably swept away.
These conglomerates are very friable, and easily decomposed; and I am inclined to think this formation is the source from which was derived the great deposite of sand and gravel which forms the surface rock of the prairie country west of the Mississippi.
Crossing the ridge of red sandstone, and traversing the little prairie which lies to the southward of it, we made in the afternoon an excursion to a place which we called the Hot Spring Gate. This place has much the appearance of a gate, by which the Platte passes through a ridge composed of a white and calcareous sandstone. The length of the passage is about four hundred yards, with a smooth green prairie on either side. Through this place, the stream flows with a quiet current, unbroken by any rapid, and is about seventy yards wide between the walls, which rise perpendicularly from the water. To that on the right bank, which is the lower, the barometer gave a height of three hundred and sixty feet. This place will be more particularly described hereafter, as we passed through it on our return.
We saw here numerous herds of mountain sheep, and frequently heard the volley of rattling stones which accompanied their rapid descent down the steep hills. This was the first place at which we had killed any of these animals; and, in consequence of this circumstance, and of the abundance of these sheep or goats, (for they are called by each name,) we gave our encampment the name of Goat Island. Their flesh is much esteemed by the hunters, and has very much the flavor of Alleghany mountain sheep. I have frequently seen the horns of this animal three feet long and seventeen inches in circumference at the base, weighing eleven pounds. But two or three of these were killed by our party at this place, and of these the horns were small. The use of these horns seems to be to protect the animal's head in pitching down precipices to avoid pursuing wolves--their only safety being in places where they cannot be followed. The bones are very strong and solid, the marrow occupying but a very small portion of the bone in the leg, about the thickness of a rye straw. The hair is short, resembling the winter color of our common deer, which it nearly approaches in size and appearance. Except in the horns, it has no resemblance whatever to the goat. The longitude of this place, resulting from chronometer and lunar distances, and an occultation of Arietis, is 107° 13' 29", and the latitude 42° 33' 27". One of our horses, which had given out, we left to receive strength on the island, intending to take her, perhaps, on our return.
31st.--This morning we left the course of the Platte, to cross over to the Sweet Water. Our way, for a few miles, lay up the sandy bed of a dry creek, in which I found several interesting plants. Leaving this, we wended our way to the summit of the hills, of which the peaks are here eight hundred feet above the Platte, bare and rocky. A long and gradual slope led from these hills to the Sweet Water, which we reached in fifteen miles from Goat Island. I made an early encampment here, in order to give the hunters an opportunity to procure a supply from several bands of buffalo, which made their appearance in the valley near by. The stream is about sixty feet wide, and at this time twelve to eighteen inches deep, with a very moderate current.
The adjoining prairies are sandy, but the immediate river bottom is a good soil, which afforded an abundance of soft green grass to our horses, and where I found a variety of interesting plants, which made their appearance for the first time. A rain to-night made it unpleasantly cold; and there was no tree here, to enable us to pitch our single tent, the poles of which had been left at our Cache camp. We had, therefore, no shelter except what was to be found under cover of the absinthe bushes, which grew in many thick patches, one or two and sometimes three feet high.