It is also about thirty miles below the falls that the range of high land, called the knobs, intersects the river. This is the ridge that crosses the lower part of Indiana, and part of Kentucky, which the late M. Volney noticed under the name of the Silver Creek hills; and by him supposed to have once formed a dam, that retained a lake in the valley of the Ohio, extending from the ridge just mentioned, to the place where Pittsburg now stands. That philosopher attempted to show that the higher bottom lands, which are above the level of the present inundations, were deposited in the bottom of the lake; and that, on the water’s making a gap in the barrier, the lake was drained, and the Ohio withdrawn into its present lower and less capacious bed. That the knobs once formed a dam I am forced to admit, from having seen marks on a high level on the limestone rocks in the gap, which {258} clearly indicate the action of a cataract: but I am, notwithstanding, led to agree with Dr. Drake’s hypothesis, which explains the formation of the higher bottom land, as being the alluvion of the Ohio at a time when that river was much larger than at present. The facts relating to this subject that have come within the reach of my own observation, may perhaps be inserted in a well-known scientific journal. In the meantime, it may be sufficient to say, it is now ascertained, that the waters of Erie, and other great lakes, formerly flowed southward into the valley of the Ohio; and that a cataract, more tremendous than the falls of Niagara, raged among the rocks of Silver Creek hills. In the neighbourhood of Salt River and Green River, in Kentucky, there are extensive tracks of barren wastes. Small hazel bushes from two to three feet in height abound in these; and the quantity of nuts produced exceeds any thing of the kind which I have ever seen. The soil of these wastes seems to be very similar to that of the adjoining woods; and on account of the trees diminishing gradually in size, from the forest toward the waste, it is sometimes impossible to discover a line where the one stops and the other begins. This, together with the fact told by an old settler, that some small saplings which stood on his farm twenty years ago, are now become tall trees, leads me to adopt the opinion entertained by some, that the wastes or barrens owe their characteristic form to the Indians, who set fire to dried grass and other vegetables with the design of facilitating their hunting.