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THE POPULAR SCIENCE MONTHLY.

channel, and these narrow canons are so close to each other as to be separated by walls of rock so steep, in most places, that they cannot be scaled, and many of these little cañons are so broken by falls as to be impassable in either direction.

The whole country is cut, in this way, into irregular, angular blocks, standing as buttresses, benches, and towers, about deep water-ways and gloomy alcoves.

The conditions under which the cañons have been carved will be more elaborately discussed hereafter.

To the west of Green River, and back some miles, between Black's Fork and Henry's Fork, we have a region of buff, chocolate, and lead-colored Bad Lands. This Bad-Land country differs from the Alcove Land, above mentioned, in that its outlines are everywhere beautifully rounded, as the rocks of which it is composed crumble quickly under atmospheric agencies, so that an exposure of solid rock is rarely seen; but we have the same abrupt descent of the streams, and the same elaborate system of water-channels. Here we have loose, incoherent sandstones, shales, and clays, carved, by a net-work of running waters, into domes and cones, with flowing outlines. But still there is no vegetation, and the loose earth is naked. Occasionally, a thin stratum of harder rock will be found. Such strata will here and there form shelves or steps upon the sides of the mountains.

Traces of iron, and rarer minerals, are found in these beds, and, on exposure to the air, the chemical agencies give a greater variety of colors, so that the mountains and cones, and the strange forms of the Bad Lands, are elaborately and beautifully painted; not with the delicate tints of verdure, but with brilliant colors, that, are gorgeous when first seen, but which soon pall on the senses.

The Uinta Mountains.—To the west of Green River stand the Wasatch Mountains, a system of peaks, tables, and elevated valleys, having a northerly and southerly direction, nearly parallel to the river. The range known as the Uinta Mountains stands at right angles to the Wasatch, extending toward the east, and no definite line of division can be noticed. The Wasatch is a great trunk, with a branch called the Uinta. Near the junction, the two ranges have about the same altitude, and the gulches of their summits are filled with perpetual snow; but, toward the east, the Uinta peaks are lower, gradually diminishing in altitude, until they are lost in low ridges and hills. Through this range Green River runs, and a series of cañons forms its channel.

To a person studying the physical geography of this country, without a knowledge of its geology, it would seem very strange that the river should cut through the mountains, when apparently it might have passed around them to the east, through valleys, for there are such along the north side of the Uintas, extending to the east, where the mountains are degraded to hills; and, passing around these, there