current, which, in an elevated stage, roars and foams with great velocity. About three or four miles up the Pottoe, this rock is underlayed by a bituminous slate-clay, indicative of coal, beneath which, no doubt, would be found calcareous rock; neither this nor the sandstone, however, present any organic remains.
3d.] To-day, accompanied by Doctor Russel, and another gentleman of the fort, I rode to Cedar prairie, lying about 10 miles south-east of the garrison, and presenting an irregular or undulating surface. I here found a second species of that interesting plant, which my venerable friend, William Bartram,[172] called Ixia cœlestina;[173] the flowers of this species are also of a beautiful blue, and white at the base. The whole plain was, in places, enlivened with the Sysirinchium anceps, producing flowers of an uncommon magnitude; amidst this assemblage it was not easy to lose sight of the azure larkspur,[174] whose flowers are of the brightest ultramarine; in the depressions also grew the ochroleucous Baptisia,[175] loaded with papilionaceous flowers, nearly as large as those of the garden pea.
From this prairie, and more particularly from a hill which partly traverses it, the mountains of the Pottoe appeared quite distinct, the Sugar-loaf on the east, and
