From the top of this hill, the high peak mentioned by Captain Pike, was discovered, and its bearing found to be S. 50. W.
Several of the party ascended Defile creek until they arrived at the mountains, into which they penetrated as far as was found practicable. As they travelled along the bed of this, they found the several rock formations beautifully exposed, and in the following order.
Commencing from the alluvial of the plain on the east, they saw:
First, Horizontal sandstone, embracing extensive { 201} beds of coarse conglomeratic, and commonly of a light gray or reddish yellow colour.
Second, Fine compact gray sandstone, containing a few impressions of organized remains, resembling those in the sandstones of coal formations. This rock is inclined at an angle of near twenty degrees towards the west. It forms continuous ranges of hills, not difficult of ascent from the east, but their western declivities are abrupt and precipitous.
Third, Lofty and detached columns of sandstone, of a reddish or deep brown colour. These are irregularly scattered throughout a narrow untimbered valley. Some of them rise probably three hundred feet above the common level of the plain, and are so steep on all sides as to preclude the possibility of ascent. Others are accessible at some points, and one of these we ascended. Sketches of these singular rocks have been preserved both by Mr. Peale and Mr. Seymour.
Fourth, Coarse white pudding-stone or conglomeratic and sandstone, of a deep red colour, alternating with each other, and with beds of fine white sandstone, and resting against the granite in a highly inclined position. This rock contains well preserved remains of terebratulæ, productus, and other bivalve shells. These are usually found on or near the surface of large nodules of a fine flinty stone, closely resembling petrosilex. The same rock also contains an extensive bed of iron ore; and from its eastern side flows a copious brine spring.
About this spring, which had evidently been much frequented by animals, we saw the skulls of the male and female big horn, the bones of elk, bisons, and other animals.
The granite, which succeeds the sandstone last mentioned, is of a dark reddish brown colour, containing a large proportion of felspar, of the flesh-coloured variety, and black mica. The crystalline grains, or fragments of the felspar, are large, and { 202} detached easily, so that the rock is in a state of rapid disintegration. This granite rises abruptly in immense mountain masses, and undoubtedly extends far to the west.