waters of an aqueduct, and to the great hazard and terror of the people in the valleys, every spring. M. de Prony, who has recently been employed by government, to examine the present condition of this river, and if possible to suggest some method of security against a catastrophe which every year threatens the lives and property of so many inhabitants, ascertained that the bed of the Po is now higher than the roofs of the houses, in the city of Ferrara, near which it runs. The magnitude of these barriers, already so immense, it is found necessary to increase every year, to prevent an inundation.-Lyell and Cuvier. When we consider that the smallest stream breaking through or running over this embankment, would, if not discovered within a few seconds, destroy in spite of all human power, many cities, towns, and villages, with all their inhabitants, we may in some degree conceive of the constant anxiety which those must feel who reside within the danger. Falls of Niagara. This is the most magnificent waterfall in the world. It is situated between lake Erie above, and lake Ontario below, the cataract being formed by the passage of the water, from one lake to the other. The distance between the nearest shores of these lakes is about thirty-seven miles, and the height of Erie above Ontario is, according to Mr. Featherstonhaugh, 322 feet. On flowing out of the upper lake, the river is almost on a level with its banks, so that if it should rise perpendicularly eight or ten feet, it would lay under water the adjacent flat couutry of Upper Canada on the west, and part of the State of New-York on the east. The river where it issues, is about twenty-five feet deep, and three quarters of a mile wide. Its descent is fifty feet in half a mile. Goat Island at the very verge of the cataract divides the water into two parts. The stream on the American side is 1,072 feet wide; and the curvature of the great Horse-shoe fall is 2,376 feet wide, making the width of the whole at the falls, 3,448 feet. Although the aggregate descent from Erie to Ontario is 322 feet, the perpendicular fall at the cataract is less than one half this distance. The following particulars are from Mr. Featherstonhaugh's journal. Fall from Erie to the rapids above the Cataract of Niagara, Fall of the rapids to the edge of the Cata ract, Fall of the Horse-shoe Cataract, There is no doubt but the Falls of Niagara at some remote period, were at Queenstown, which is about seven miles below there present situation. The breadth of the gorge or excavation made by the waters, is, on approaching the falls, about 1200 feet, but is much narrower towards Queenstown. The kind of rock through which it passes consists of limestone and shale, the latter a dark colored shelly formation, 80 feet thick, lying under the limestone. The limestone is 70 feet thick, above which is the ordinary soil of the country. The limestone is hard and lies in horrizontal strata at the edge of the falls; but the shale is soft, and is acted upon with much greater facility than the limestone, so that the latter rock often overhangs the former perhaps 40 feet at the edge of the precipice. The blasts of wind charged with spray, which rise out of the pool into which this enormous cascade is projected, strike against the shale beds, so that their disintegration is constant; and the superincumbent projecting limestone being left without a foundation, falls from time to time in immense rocky masses. When these enormous fragments fall, a shock is felt, often at considerable distances, accompanied by a noise resembling a distant clap of thunder. The waters which expand at the falls, where they are divided by the island, are contracted again after their union, into a stream averaging not more than 500 feet broad. In the narrow channel, immediately below this immense rush of waters, a boat may pass across the stream with safety. The pool into which the cataract is precipitated being 170 feet deep, the descending water sinks down and forms an under current, while a superficial eddy carries the upper stratum back towards the main fall.-See Mr. Bakewell, Jr., on the Falls of Niagara, London Magazine, 1830. There is no doubt but the falls of Niagara were once at Queenstown, as above stated, and have gradually cut their way through the rock to their present situation. Mr. Lyell who refers all the changes which have taken place on the earth's surface "to causes now in operation," states that the recession of the falls have been at the rate of fifty yards in forty years, and therefore a little more than three feet on an average in each year. "If the ratio of recession," says he, "had never exceeded fifty yards in forty years, it must have required nearly ten thousand years for the excavation of the whole ravine; but no probable conjecture can be offered as to the quantity of time consumed in such an operation, because the retrograde movement may have been much more rapid, when the whole current was confined within a space not exceeding a fourth, or a fifth part of that which the falls now occupy. Should the erosive action not be accelerated in future, it will take upwards of thirty thousand years for the falls to reach lake Erie, (twenty-five miles distant) to which they seem destined to arrive in the course of time, unless some earthquake changes the relative levels of the districts. The table land extending from lake Erie, consists uniformly of the same geological formations as are now exposed at the falls. The upper stratum is an ancient alluvial sand varying in thickness from 10 to 140 feet; below which is a bed of hard limestone about 90 feet in thickness, stretching nearly in a horizontal direction over the whole country, and forming the bed of the river above the falls, as do the inferior shales below. The lower shale is nearly of the same thickness of the limestone." "Should lake Erie remain in its present state until the period when the ravine recedes to its shores, the sudden escape of that great body of water would cause a tremendous deluge, for the ravine would be more than sufficient [in depth we suppose,] to drain the whole lake, of which the average depth was found, during the late surveys to be ten or twelve fathoms."-Lyell's Geology, vol. i. page 179-182. Such is the tenor of Mr. Lyell's reasoning, when attempting to "explain the former changes of the earth's surface by reference to causes now in operation;" and thus to deny the Mosaic history of the creation, and of the deluge. Although he owns that no probable conjecture can be afforded, with respect to the time which has elapsed since the falls of Niagara were at Queenstown, still, it is obvious that the impression intended to be left on the mind of the reader is, that it was about 10,000 years ago; that is about 4000 years before the creation of the world according to Moses, these falls were at Queenstown. And at some future period, say 30,000 years hence, there will be a great flood in America, just as there have happened great floods at different periods according to what he calls the “uuiformity of the order of nature." Now let us see, in the first place, whether the data stated by the author, can possibly warrant the supposition that the falls of Niagara have been 10,000 years, or even half that time in passing from Queenstown to their present location, Mr. Lyell, who quotes Capt. Basil Hall for his authority, makes the falls 800 yards wide at the verge of the precipice; viz. the American fall 200 yards, and the Horseshoe fall 600 yards wide. The channel below the falls towards Queenstown, according to the same authority, is 160 yards wide. Mr. Featherstonhaugh, (Monthly American Journal, No. 1,) we have already seen, makes all these widths more considerable. But we will take Mr. Lyell's own account. The old channel being 160 yards wide, is exactly one fifth the width of the present falls. Now supposing the retrograde movement of the cataract had been in proportion to its width, then according to Mr. Lyell's estimate it could have been only 2000 years in travelling from Queenstown to its present place; for 160 being a fifth of 800, and allowing the present movement to be at the rate of seven miles in 10,000 years, then, being only a fifth as wide, anciently as now, there is reason to believe that it moved at least five times as fast. But reasoning from the data before us, the time must have been even less than 2000 years, for it is plain that a given quantity of water, say a yard in breadth, would perform the work of excavation more than five times as rapidly as it would if spread over five yards in breadth. It is however but fair to state that the falls at Queenstown were not so high as they are at present, and therefore, estimating the quantity of water the same as at present, the movement must have been slower than now. For, we know that the denudating, or excavating power of water, bears not only a proportion to its depth and rapidity, but also to the height from which it falls, so that cataracts of little elevation produce no perceptible effects for centuries, while, if the same quantity of water were precipitated from a height of several hundred feet, the whole precipice would gradually retrograde up the stream. Allowing, therefore, that the falls moved only at half the rate above estimated, this would fix the time at 4000 years since they were at Queenstown. Now, without giving any opinion as to the real epoch, when this cataract was at Queenstown, for there are no grounds on which such an opinion ought to be formed; still we must be permitted to say that according to the data Mr. Lyell has given us, it is quite plain that the cataract of Niagara could not have been more than 3 or 4000 years in moving from Queenstown to its present place, instead of 10,000 years, which impression, if any, he con veys. American Deluge. With respect to the deluge which Mr. Lyell predicts will happen about 30,000 years hence in North America, we will state the grounds on which his profoundly scientific vision presages a catastrophe so awful to this devoted country. **** 19 "It was," says he, "contrary to analogy to suppose that nature had been at any former epoch, parsimonious of time, and prodigal of violence, to imagine that one district was not at rest while another was convulsed-that the disturbing forces were not kept under subjection, so as never to carry simultaneous desolation over the whole earth, or even over one great region. "In speculating on catastrophes by water we may certainly expect great floods in future, and we therefore presume that they have happened again, and again in past times. The existence of enormous seas of fresh water, such as the North American lakes, the largest of which is elevated more than 600 feet above the level of the ocean, and is in part 1200 feet deep, is alone sufficient to assure us, that the time will come, however distant, when a deluge will lay waste a considerable part of the American continent. No hypothetical agency is required to cause the sudden escape of |