"July 18.--This morning we saw a large herd of the big-horned animals, who were bounding among the rocks in the opposite cliff with great agility. These inaccessible spots secure them from all their enemies; and the only danger they encounter is in wandering among these precipices, where we should suppose it scarcely possible for any animal to stand. A single false step would precipitate them at least five hundred feet into the river. "The game continues abundant. We killed to-day the largest male elk we have yet seen. On placing it in its natural, erect position, we found that it measured five feet three inches from the point of the hoof to the top of the shoulder. "The antelopes are yet lean. This fleet and quick-sighted animal is generally the victim of its curiosity. When they first see the hunters, they run with great velocity. If the hunter lies down on the ground, and lifts up his arm, his hat, or his foot, the antelope returns on a light trot to look at the object, and sometimes goes and returns two or three times, till at last he approaches within reach of the rifle. So, too, they sometimes leave their flock to go and look at the wolves, who crouch down, and, if the antelope be frightened at first, repeat the same manoeuvre, and sometimes relieve each other, till they decoy the antelope from his party near enough to seize it." THE GATES OF THE ROCKY MOUNTAINS. "July 20.--During the day, in the confined valley through which we are passing, the heat is almost insupportable; yet, whenever we obtain a glimpse of the lofty tops of the mountains, we are tantalized with a view of the snow. A mile and a half farther on, the rocks approach the river on both sides, forming a most sublime and extraordinary spectacle. For six miles, these rocks rise perpendicularly from the water's edge to the height of nearly twelve hundred feet. They are composed of a black granite near the base; but judging from its lighter color above, and from fragments that have fallen from it, we suppose the upper part to be flint, of a yellowish-brown and cream color. Nothing can be imagined more tremendous than the frowning darkness of these rocks, which project over the river, and menace us with destruction. The river, one hundred and fifty yards in width, seems to have forced its channel down this solid mass: but so reluctantly has it given way, that, during the whole distance, the water is very deep even at the edges; and, for the first three miles, there is not a spot, except one of a few yards in extent, on which a man could stand between the water and the towering perpendicular of the mountain. The convulsion of the passage must have been terrible; since, at its outlet, there are vast columns of rock torn from the mountain, which are strewed on both sides of the river, the trophies, as it were, of victory. We were obliged to go on some time after dark, not being able to find a spot large enough to encamp on.