From what we have seen of the wide waste and decay everywhere in progress on the solid lands of our planet, it becomes no difficult matter to perceive what a number of agencies must be at work in the formation of a river channel. Let the reader take his stand in some wooded ravine, where the shelving rocks on either side are hung all over with verdure, and a tiny streamlet murmurs on beneath with a flow so quiet and gentle as scarcely to shake the long pendant willow branches that dip into its surface, while the polished pebbles that strew its bed lie unmoved by the rippling current that glides over them. If in the midst of such a scene the question were to arise in his mind, How came this deep, narrow ravine into existence? what answer would in all likelihood be the first to suggest itself? His eye would scan the precipitous walls of the dell, with their rocks cleft through to a depth of perchance fifty feet. It would require no great scrutiny to assure him that the beds on the one side formed the onward prolongations of those on the other, and that consequently there must have been a time ere yet the ravine existed, when these beds stretched along unbroken. Satisfied with these results, his first impulse might be to bethink him of some primeval earthquake, when the solid land rocked to and fro like a tempested sea, and broke up into great rents and yawning chasms. Into one of these clefts he might suppose the little streamlet had eventually found its way, moistening the bare and barren rocks, until at length their surface put on a livery of moss, or lichen, or liver-wort, and the birch, the alder, and the willow, found a nestling-place in their crevices. Such a view of the origin of the woody dell would be certainly a very natural one, and in some instances might be sufficiently correct, but in the present case it will not explain the phenomena. If the reader will kindly permit me to visit the locality in his company, perhaps we may be able to light upon the true explanation, and see a few appearances worthy our attention.