The first entry by Clark is made just four days after departing St. Charles on the Missouri River.
Cpt. Clark, May 25, 1805--The country on either side is high broken and rockey a dark brown hard rugid stone intermixed with a soft white sand stone. the hills contain coal or cabonated wood as below and some scattering pumestone. the sides of the river is bordered with coars gravel, which in maney places have washed either together or down small brooks and forms bars at some distance in the water, around which the current passes with great valocity. the bottoms between hills and river are narrow and contain scercely any timber. we saw a polecat today being the first which we have seen for some time past. The Air of this quarter is pure and helthy. the water of the Missouri will tasted not quite so muddy as it is below, not withstanding the last rains has raised the river a little it is less muddy than it was before the rain.
Lewis writes from Fort Clatsop.
Capt. Lewis, February 28, 1806--The Pole-cat is also found in every part of the country. they are very abundant on some parts of the columbia, particularly in the neighbourhood of the great falls and narrows of that river, where the[y] live in the clifts along the river and feed on the offal of the Indian fishing shores. these are the same as those of other parts of North America.