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Show 180 FALLS OF NIAGARA. . . . bout three quarters of a East*. The river, where It Is~ues, lis ~ lis it is propelled with mile in 'd 1 B fore rcachmg t1c a ' .r. d w1 t 1. e . b. d b ut twenty-five .iect eep, great rapi'd I' ty' b el'n cr a nnle roa 'a o . A . 1 d o ft feet in half a mile. n Is an and having a descent of fi y t divides it into two sheets of f the catarac . . d d at the very verge o 1 d th Horse-shoe Fall, IS SIX hun re water; one of these, cal e de d flfty"eight feet perpendicular; Yards wide, and one hund~e aFn lllsi·s about two hundred yards 11 d th Amencan ~a . ' the other, ca e e d d . ty-four feet in height. The in width , an d one hund. re b an fis ix hundred yards. '1'11 I•S great breadth of the island .Is. a oudt ve lcdcre of hard limestone, in . ecipitate over a o . k sheet of water IS pr 1 . 1 . somewhat greater thiC ness hori.z onta1 strat a, below WliCld IS .a mules away more rap1' dl y, so h 1 1. ch decays an cru . . of soft s a e, w 11 1 £ ms an overhanging mass, proJectmg that the calcareous roc<. ~~e hollow space below. The bl~sts forty feet or more above h. h rise out of the pool mto of wind, charged with sprady' "! Ipcroiected strike against the 1 · ous casca e IS " ' which t liS enorm d. . t tion is constant; and the super-shale beds, so that their .Isml efgra 'thout a foundation, falls from b t 1. stone bemg e t WI incum en· 1m· e cky' masses Wll en these enormous fragmen·t s time to time m ro . d' t nee accompanied by a nmse h 1 . £ lt at some IS a ' descend, as oc <.IS e After the river has passed over like a distant clap of thunder. C t in Hall is immediately and the falls, its character' observes ap af riousiy along the bottom 1 h d It then runs u complete y c ange . 1 trench which has been cut of a deep wall-sided valley, or mge t' a' action of the stream . t 1 trata by the con mue . into the horizon a s The cliffs on both sides are m most during the lap~e of agesd he ravine is only perceived on ap-places perpendicular, an t . . t . . h d f the preCipiCe . d' 'd d proachmg t e e ~eo d the falls, where they are ~vl e The waters which expan ;t . fter their union, mto a by the island, are contrac~eun;;:ln~n~ sixty yards broad. In stream not more than one . l b l this immense rush of the narrow channel, immediate y e ow . th ease The pool, water a boat can pass acr· oss the . stream. W't l ted bei·n O' one hu n· it is s~id, into which the catara~ ~~ precl~~nacr w~ter sinks down dred and seventy feet deep, t e escen o • Ca tain Hall's Travels in North Amen.c a, vo l.i. , p.l79. p t Ibid., PP· 195, 196, 216. FALLS OF NIAGARA. 181 and forms an under-current, while a superficial eddy carnes the upper stratum back towards the main fall*. This is not improbable; and we must also _suppose, that the confluence of two streams, which meet at a considerable angle, tends mutually to neutmlize their forces. The bed of the river below the falls is strewed over with huge fragments which have been hurled down into the abyss. By the continued destruction of the rocks, the falls. have, within the last forty years, receded nearly fifty yards, or, in other words, the ravine has been prolonged to that extent. 'l'hrough this deep chasm the Niagara flows for about seven miles; and then the table-land, which is almost on a level with Lake Erie, suddenly sinks down at a town called Queenstown, and the river emerges from the ravine into a plain which continues to the shores of Lake Ontario;-. There seems good foundation for the general opinion, that the falls were once at Queenstown, and that they have gradually retrograded from that place to their present position, about seven miles distant. If the ratio of recession 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 exceedinO' a fourt~ or fif~h of that which the faHs now occupy. Should the eros1ve action not be accelerated in future, it will require upwards of thirty thousand years for the falls to reach Lake E6e (twenty-five miles distant), to which they seem destined to arrive i~ the course of time, unless some earthquake chan?es the relative levels of the district. The table-land, extendmg fr?m Lake Erie, consists uniformly of the same geological formatiOns as are now exposed to view at the falls. The upper stratum is an ancient alluvial sand, varying in thickness from ten to one hundred and forty feet ; below wl1ich is a bed • See Mr. Bakewell, jun., on Falls of Niagara. Loudon's Magazine No. 12 March, 1830. ' ' +.The Memoir of Mr. Bakewell, jun. above referred to, contains two very illustrative sketches of tho physical geography of the country between Lakes Erie and Ontario, including the falls. |