They were returning from an expedition against the Shoshonee Indians, one of whose villages they had surprised, at Bridger's fort, on Ham's fork of Green river, (in the absence of the men, who were engaged in an antelope surround,) and succeeded in carrying off their horses, and taking several scalps. News of the attack reached the Snakes immediately, who pursued and overtook them, and recovered their horses; and, in the running fight which ensued, the Arapahoes had lost several men killed, and a number wounded, who were coming on more slowly with a party in the rear. Nearly all the horses they had brought off were the property of the whites at the fort. After remaining until nearly sunset, they took their departure; and the excitement which their arrival had afforded subsided into our usual quiet, a little enlivened by the vigilance rendered necessary by the neighborhood of our uncertain visiters. At noon the thermometer was at 75°, at sunset 70°, and the evening clear. Elevation above the sea 6,820 feet; latitude 41° 36' 00"; longitude 107° 22' 27".
6th.--At sunrise the thermometer was 46°, the morning being clear and calm. We traveled to-day over an extremely rugged country, barren and uninteresting--nothing to be seen but artemisia bushes; and, in the evening, found a grassy spot among the hills, kept green by several springs, where we encamped late. Within a few hundred yards was a very pretty little stream of clear cool water, whose green banks looked refreshing among the dry, rocky hills. The hunters brought in a fat mountain sheep, (_ovis montana_.)
Our road the next day was through a continued and dense field of _artemisia_, which now entirely covered the country in such a luxuriant growth that it was difficult and laborious for a man on foot to force his way through, and nearly impracticable for our light carriages. The region through which we were traveling was a high plateau, constituting the dividing ridge between the waters of the Atlantic and Pacific oceans, and extending to a considerable distance southward, from the neighborhood of the Table rock, at the southern side of the South Pass. Though broken up into rugged and rocky hills of a dry and barren nature, it has nothing of a mountainous character; the small streams which occasionally occur belonging neither to the Platte nor the Colorado, but losing themselves either in the sand or in small lakes. From an eminence, in the afternoon, a mountainous range became visible in the north, in which were recognised some rocky peaks belonging to the range of the Sweet Water valley; and, determining to abandon any further attempt to struggle through this almost impracticable country, we turned our course directly north, towards a pass in the valley of the Sweet Water river. A shaft of the gun-carriage was broken during the afternoon, causing a considerable delay; and it was late in an unpleasant evening before we succeeded in finding a very poor encampment, where there was a little water in a deep trench of a creek, and some scanty grass among the shrubs. All the game here consisted of a few straggling buffalo bulls, and during the day there had been but very little grass, except in some green spots where it had collected around springs or shallow lakes. Within fifty miles of the Sweet Water, the country changed into a vast saline plain, in many places extremely level, occasionally resembling the flat sandy beds of shallow lakes. Here the vegetation consisted of a shrubby growth, among which were several varieties of _chenopodiaceous_ plants; but the characteristic shrub was _Fremontia vermicularis_, with smaller saline shrubs growing with singular luxuriance, and in many places holding exclusive possession of the ground.