The Recession of the Niagara Gorge

Abstract

BEFORE the survey of 1842, the only data for estimating the rate of recession of the Niagara Gorge were the observations of the people of the neighbourhood. Mr. Bakewell, in 1829, “was informed by Mr. Forsyth, the proprietor of the Pavilion Hotel on the Canada side, that during his residence of forty years the Falls had receded forty yards” (American Journal of Science, May 1857, p. 85). It is well-known that Sir Chas. Lyell, at the time of his visit to the Falls, came to the conclusion that the rate of recession was not over one foot a year. He based his estimate upon the statement of his guide, that between 1815 and 1841 the American Fall had receded forty feet. Modern investigators, basing their calculations on the surveys of 1842, 1875, and 1883, estimate the recession of the Canadian Fall at from three to five feet per year, and the age of the gorge from seven to ten thousand years (see Mr. Wesson's article in NATURE, vol. xxxii. p. 229; and Prof. Wright's “Ice Age in North America,” p. 452 seq.). A recent American publication, “The Journal of William Maclay,” a member of the Senate in the first Congress, 1789–91, brings to light the result of local observation of the recession of the Falls for the thirty years previous to the beginning of Forsyth's observations, which have generally been cited as the earliest. The passage in Maclay's journal reads:— “February 1st [1790].…. Mr. Ellicott's accounts of Niagara Falls are amazing indeed. I communicated to him my scheme of an attempt to account for the age of the world, or at least to fix the period when the water began to cut the ledge of rock over which it falls. The distance from the present pitch to where the Falls originally were, is now seven miles. For this space a tremendous channel is cut in a solid limestone rock, in all parts one hundred and fifty feet deep, but near two hundred and fifty at the mouth, or part where the attrition began. People who have known the place since Sir William Johnson took possession of it, about thirty years ago, give out that there is an attrition of twenty feet in that time. Now, if 20 feet = 30 years = 7 miles, or 36,960 feet; answer, 55,440 years” In view of the fact that since 1842 the rate of recession has varied widely, this earlier testimony, so far as it can he relied upon, is especially interesting. It is possible that the observation related to the American Falls, as did that of Sir Chas. Lyell's guide; but there is nothing to indicate it, except that this is about the present rate of recession of the American Fall as calculated by Mr. Wesson. The intelligent attitude and fertile scientific suggestion of Senator Maclay are very remarkable in 1790. It will be remembered that Hutton's “Theory of the Earth” was not published separately till 1795. Maclay seems to have anticipated men of science by many years in proposing to use the recession of the gorge as a scale for measuring geological time. Perhaps even more noteworthy is the unconcern with which he sets down his conclusion that the gorge was over 55,000 years old, at a time when geology was still confined by the narrow and seemingly impassable limits of traditional Biblical chronology. Maclay's informant, Ellicott, was a Government surveyor, and, according to the account of his life in Appleton's “Cyclopædia of American Biography,” “he was selected by Washington in 1789 to survey the land lying between Pennsylvania and Lake Erie, and during that year he made the first accurate measurement of the Niagara river from lake to lake, with the height of the falls and the descent of the rapids.” This early survey seems entirely unknown to geologists, who all refer to Hall's of 1842 as the first. Ellicott was a man of considerable attainments, a professor in West Point from 1808 to 1820, and the correspondent of Europem learned societies. He left some published writings, and works still in manuscript. Cannot the data of this survey of a century ago be found? If it proved a careful one, it would double the period of scientific observation of the recession of the gorge, and increase the certainty of any generalization. The map of Evershed's survey of 1883 was published in Science, vol. v. p. 398. In NATURE, vol. xxxii. p. 244, Mr. Garbett quotes some interesting observations from the Gentleman's Magazine, January 1751, from Kalm's description of the Falls as seen shortly before. Mr. Garbett tries to identify an island that Kalm mentions as intersecting the Falls as Luna Islet. This would give a definite point for calculation. It seems to me that an attempt to test Mr. Garbett's conjecture by the Evershed map must show that it is untenable. If I have understood him, and correctly measured in accordance with his suggestions, the recession of the Canadian Falls will have been about half a mile in the 133 years, or about twenty feet a year. Notwithstanding Kalm's small dimensions, I think he meant Goat Island, for he says the island lies parallel with the river, and Luna Islet prolonged would lie almost at right angles to the river at its lower end.