south fork for two days, merely seeking a safe fording place.  At length he encamped, caused the bodies of the wagons to be dislodged from the wheels, covered with buffalo hide, and besmeared with a compound of tallow and ashes; thus forming rude boats.  In these, they ferried their effects across the stream, which was six hundred yards wide, with a swift and strong current.  Three men were in each boat, to manage it; others waded across pushing the barks before them.  Thus all crossed in safety.  A march of nine miles took them over high rolling prairies to the north fork; their eyes being regaled with the welcome sight of herds of buffalo at a distance, some careering the plain, others grazing and reposing in the natural meadows.

Skirting along the north fork for a day or two, excessively annoyed by musquitoes and buffalo gnats, they reached, in the evening of the 17th, a small but beautiful grove, from which issued the confused notes of singing birds, the first they had heard since crossing the boundary of Missouri.  After so many days of weary travelling through a naked, monotonous and silent country, it was delightful once more to hear the song of the bird, and to behold the verdure of the grove.  It was a beautiful sunset, and a sight of the glowing rays, mantling the tree-tops and rustling branches, gladdened every heart.  They pitched their camp in the grove, kindled their fires, partook merrily of their rude fare, and resigned themselves to the sweetest sleep they had enjoyed since their outset upon the prairies.

The country now became rugged and broken.  High bluffs advanced upon the river, and forced the travellers occasionally to leave its banks and wind their course into the interior.  In one of the wild and solitary passes they were startled by the trail of four or five pedestrians, whom they supposed to be spies from some predatory camp of either Arickara or Crow Indians.  This obliged them to redouble their vigilance at night, and to keep especial watch upon their horses.  In these rugged and elevated regions they began to see the black-tailed deer, a species larger than the ordinary kind, and chiefly found in rocky and mountainous countries.  They had reached also a great buffalo range; Captain Bonneville ascended a high bluff, commanding an extensive view of the surrounding plains.  As far as his eye could reach, the country seemed absolutely blackened by innumerable herds.  No language, he says, could convey an adequate idea of the vast living mass thus presented to his eye.  He remarked that the bulls and cows generally congregated in separate herds.

Opposite to the camp at this place was a singular phenomenon, which is among the curiosities of the country.  It is called the chimney.  The lower part is a conical mound, rising out of the naked plain; from the summit shoots up a shaft or column, about one hundred and twenty feet in height, from which it derives its name.  The height of the whole, according to Captain Bonneville, is a hundred and seventy-five yards.  It is composed of indurated clay, with alternate layers of red and white sandstone, and may be seen at the distance of upward of thirty miles.