Fort Union' is the vastest and finest of the forts that the Fur Company has upon the Missouri; it is situated 2,2oo [1,765] miles from St. Louis. The gentlemen residing there overwhelmed us with civilities; they could not get over their astonishment at the dangerous journey which we had just concluded so fortunately. During our stay among them, they supplied all our wants most liberally, and at our departure for the village of the l'Iandans they loaded us with all sorts of provisions. I shall be most thankful to them all my life.
After having regenerated sundry half-breed children in the holy waters of baptism, I left the fort on the 23d of September. It took us ten days to reach the village of the Mandans. The soil along the great river is much more fertile than that of the Yellowstone; but it is still the same vast prairie, diversified with high hills, or rather mountains, guttered with ravines. The river beds are dry through part of the year; but they are swollen to a prodigious height in the rainy season. On the hillsides and in the bottoms, on the banks of the rivers, handsome groves are found here and there; but the general aspect of the region is nothing but an undulating plain, covered with sod and various plants. The soil is strongly impregnated with sulphur, copperas, alum and Glauber's salts; the strata of earth give a strong color to the rivers that traverse them, and together with the crumbling of the banks of the Missouri, impart to the water of that immense stream the materials that render it muddy.
There are some sandy places in that region,' full of natural curiosities; I noticed great trunks of trees petrified, and
s Fort Union, the most important and the most celebrated of the American Fur Company posts on the upper 1lfissouri, was founded in the fall of 1828, by the distinguished trader Kenneth McKenzie.
7 'This is the region which the distinguished geologist, Doctor F. V. Hayden, afterward made peculiarly his own. He made his first explorations here in 18$4, and, confirming Father De Smet's belief, found matter for years of labor and many subsequent expeditions.