For several days they had been directing their march towards the lofty mountain descried by Mr.Hunt and Mr.M'Kenzie on the 17th of August, the height of which rendered it a landmark over a vast extent of country.

At first it had appeared to them solitary and detached; but as they advanced towards it, it proved to be the principal summit of a chain of mountains.

Day by day it varied in form, or rather its lower peaks, and the summits of others of the chain emerged above the clear horizon, and finally the inferior line of hills which connected most of them rose to view.

So far, however, are objects discernible in the pure atmosphere of these elevated plains, that, from the place where they first descried the main mountain, they had to travel a hundred and fifty miles before they reached its base.

Here they encamped on the 30th of August, having come nearly four hundred miles since leaving the Arickara village.
The mountain which now towered above them was one of the Bighorn chain, bordered by a river, of the same name, and extending for a long distance rather east of north and west of south.