The fact of shells and other marine substances having been found in a few places, by digging in the prairies, proves nothing, or proves too much, for they are found in equal or greater quantities all over America, in the sides and near the summit of the Alleghany mountains; on the Andes, in South America, and the Alps, in Europe. The resemblance which the soil, in the low prairies, and not in the high, bears to the _alluvial_, can justly be attributed, it is presumed, to the leaves and other vegetables and light materials of which they are composed, having been washed by heavy rains, for ages past, from the higher to the lower places. This will also account for the circumstance of trees growing upon the summits of the hills of steep ascent: being thin and poor, the grass neither grows sufficiently long or thick to kill the timber when fired. They _could not_ have been islands in this fairy lake; because their summits are frequently much _lower_ than high prairie flats a few miles distant. These are facts which will be recollected by those who have ever travelled through a prairie country of any extent. But suppose it to have been proved, that the waters of Lake Erie once overspread the state of Ohio, from its present shore to Chillicothe, (a supposition which I trust has however been shown to be visionary) does it follow that the prairies were occasioned by such overflowing? If the water, by covering the country, prevented the timber from growing, should we not naturally look for the largest timber on the higher grounds which would be first forsaken by the waters, and for small timber on the low grounds, where the water remained longest? If this be true, (and it is unquestionable) we should then look for prairies on the low grounds bordering on Lakes Erie, Huron, and Michigan; and the thickly timbered country would be on the high land, near the sources of the rivers. But the contrary is absolutely the fact: we find heavy timbered land, and no _prairies_, in the low countries north of the lakes, and none south, either in Michigan territory or elsewhere, until we arrive near the sources of the rivers. It is true, that the water standing in ponds will prevent the timber from growing; but the difference is readily observed between prairies, properly so called, and those bogs.