passed over a ridge which borders or constitutes the river hills of the
Platte, consisting of huge blocks, sixty or eighty feet cube, of
decomposing granite. The cement which united them was probably of easier
decomposition, and has disappeared and left them isolate, and separated by
small spaces. Numerous horns of the mountain-goat were lying among the
rocks; and in the ravines were cedars, whose trunks were of extraordinary
size. From this ridge we descended to a small open plain, at the mouth of
the Sweet Water, which rushed with a rapid current into the Platte, here
flowing along in a broad and apparently deep stream, which seemed, from
its turbid appearance, to be considerably swollen. I obtained here some
astronomical observations, and the afternoon was spent in getting our boat
ready for navigation the next day.

24th.--We started before sunrise, intending to breakfast at Goat island. I
had directed the land party, in charge of Bernier, to proceed to this
place, where they were to remain, should they find no note to apprize them
of our having passed. In the event of receiving this information, they
were to continue their route, passing by certain places which had been
designated. Mr. Preuss accompanied me, and with us were five of my best
men, viz.: C. Lambert, Basil Lajeunesse, Honore Ayot, Benoist, and
Descoteaux. Here appeared no scarcity of water, and we took on board, with
various instruments and baggage, provisions for ten or twelve days. We
paddled down the river rapidly, for our little craft was light as a duck
on the water; and the sun had been some time risen, when we heard before
us a hollow roar, which we supposed to be that of a fall, of which we had
heard a vague rumor, but whose exact locality no one had been able to
describe to us. We were approaching a ridge, through which the river
passes by a place called "canon," (pronounced _kanyon_,)--a Spanish
word, signifying a piece of artillery, the barrel of a gun, or any kind of
tube; and which, in this country, has been adopted to describe the passage