- utes to the same fiery cause. That the prairies have
been {303} lakes of water he much doubts. General Evans, a gentleman with whom I, this day, held an interesting conversation on the subject, and who has explored the prairie country generally, thinks that as they are contiguous to the immense lakes of Michigan, &c. without being intercepted by any hills of magnitude, they must have been formed by the receding of the lakes of which they once constituted a part, and to this day, in the sand, traces of surf and driving water are still evident on and round about the gentle hills and skirts of the prairies. This idea is opposed by some, because, of the prairie rivers, some are found running north into the lakes, and others south into the Ohio and the Mississipi. The soil and sand, however, of the prairies, are such as are found on the lake shores, and shew, upon and below the surface, the operations of water.
For the general purposes of agriculture, the intelligent General considers the best prairie soil to be deeper and more lasting than the woodland, though at present more uncertain. It wants more rain, and frequently fails in droughty seasons. Cultivation, he conceives, will render it less porous and more retentive of moisture: time is necessary for rotting the tough, wiry grass-roots; its richness and durability are proved by its having been constantly in cultivation at Vincennes, during the last 200 years. The best prairies known in this country, abounding with healthy situations, and {304} fine running never-failing springs, sufficient for mill-streams, he saw from 70 to 100 miles above Birkbeck's, on the banks of the Wabash, up to its head waters, beyond Fort Harrison,[97]
