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'.