On reaching the second chain, called the Bighorn Mountains, where the river forced its impetuous way through a precipitous defile, with cascades and rapids, the travellers were obliged to leave its banks, and traverse the mountains by a rugged and frightful route, emphatically called the “Bad Pass.”  Descending the opposite side, they again made for the river banks; and about the middle of August, reached the point below the rapids where the river becomes navigable for boats.  Here Captain Bonneville detached a second party of trappers, consisting of ten men, to seek and join those whom he had detached while on the route; appointing for them the same rendezvous, (at the Medicine Lodge,) on the 28th of August.

All hands now set to work to construct “bull boats,” as they are technically called; a light, fragile kind of bark, characteristic of the expedients and inventions of the wilderness; being formed of buffalo skins, stretched on frames.  They are sometimes, also, called skin boats.  Wyeth was the first ready; and, with his usual promptness and hardihood, launched his frail bark, singly, on this wild and hazardous voyage, down an almost interminable succession of rivers, winding through countries teeming with savage hordes.  Milton Sublette, his former fellow traveller, and his companion in the battle scenes of Pierre’s Hole, took passage in his boat.  His crew consisted of two white men, and two Indians.  We shall hear further of Wyeth, and his wild voyage, in the course of our wanderings about the Far West.

The remaining parties soon completed their several armaments.  That of Captain Bonneville was composed of three bull boats, in which he embarked all his peltries, giving them in charge of Mr. Cerre, with a party of thirty-six men.  Mr. Campbell took command of his own boats, and the little squadrons were soon gliding down the bright current of the Bighorn.

The secret precautions which Captain Bonneville had taken to throw his men first into the trapping ground west of the Bighorn, were, probably, superfluous.  It did not appear that Fitzpatrick had intended to hunt in that direction.  The moment Mr. Campbell and his men embarked with the peltries, Fitzpatrick took charge of all the horses, amounting to above a hundred, and struck off to the east, to trap upon Littlehorn, Powder, and Tongue rivers.  He was accompanied by Captain Stewart, who was desirous of having a range about the Crow country.  Of the adventures they met with in that region of vagabonds and horse stealers, we shall have something to relate hereafter.

Captain Bonneville being now left to prosecute his trapping campaign without rivalry, set out, on the 17th of August, for the rendezvous at Medicine Lodge.  He had but four men remaining with him, and forty-six horses to take care of; with these he had to make his way over mountain and plain, through a marauding, horse-stealing region, full of peril for a numerous cavalcade so slightly manned.  He addressed himself to his difficult journey, however, with his usual alacrity of spirit.