Missouri River above Great Falls, Gates of the Mountains — Patrick Gass: July 19, 1805

of the mountains, which had a good deal of pine, spruce and
cedar on them, and where there were not so many rocks;
but no timber in the bottoms except some small willows.
About 1 o’clock we had thunder, lightning and rain, which
continued an hour or two, and then the weather became clear.
This afternoon we passed parts of the mountains, that were
very high, and mostly of solid rock of a light colour. The
Mountains are so close on the river on both sides that we
scarcely could find room to encamp. We went 20 miles and
encamped on the south side. After night some rain fell.