The giant masonry of Nature, which has so long interposed a barrier against the draining of Lake Erie into Ontario at a rush, and the consequent overwhelming of all the dwellers upon the latter and the St. Lawrence by a deluge, is evidently wearing away; I can perceive a decided change since I first stood here, seven years ago. The main or British fall is receding near the middle, and thus exchanging its original (or recent) form of a horseshoe for that of an irregular wedge. By this process the beauty and grandeur of the cataract are sensibly diminished. I understand that the recession here, under the pressure of so vast a body of water, has been so rapid as essentially to diminish the amount of water flowing on the American side of Goat Island, even within twenty years. Five hundred will probably suffice to dry this channel altogether; five thousand may or may not suffice to bring on the great convulsion which will destroy the falls entirely, change Lake Erie into a sandy valley divided by a rapid river, leave one half the Erie Canal without water, and change the whole face of Nature from Detroit to the Ocean, And why from Detroit only? It _may_ be that a barrier of rock equally firm prevents the immediate occurrence of a similar convulsion at the mouths of the Huron and Michigan, and thus the cataract will but be transferred to a point much nearer the Superior; yet I should deem it quite as likely that the final submersion of Niagara, if instantaneous, as it very probably will be, when the rocky barrier has been sapped and broken down so nearly through as no longer to afford adequate resistance to the intense pressure of Lake Erie, will be the signal for a convulsion so mighty as to change the whole topography of Central North America. Since I wrote the foregoing, I have slept to the music of the great cataract, my window looking out on the foaming and hurrying waters of the American current, just before it is precipitated over the ledge. It has rained through a good part of the night, though the roar of the waters drowned completely the noise of the storm, and the morning is wet and forbidding, while a heavy fog or cloud detracts much from the grandeur of the scene. My morning walk along the American shore has been less satisfactory than any previous observation, the water suspended in vapor somewhat shrouding the spectacle, while that falling or fallen detracts likewise from the comfort of all but web-footed travellers. No matter—I did not meditate any precise description of the Fall, and shall not attempt it. The readers of your Magazine, I presume, are mainly of the class who have either been here or intend to see for themselves at a fitting season. And beside, description avails very little in such a case. It is only by its comparisons and assimilations of the unknown with the known that description enlightens—and what has the world to compare with Niagara?