NIAGARA RIVER AND FALLS (Iroquois Jorakare, thundering water). The Niagara River flows from Lake Erie to Lake Ontario, and is the outlet for the whole drainage of lakes Su perior, 'Huron. Michigan. Saint Clair, and Erie. The surface of Erie. where the river begins, is 326 feet higher than the level of Ontario, where it ends. The water is clear and pure. The river is 33 miles long, its general direction is from south to north, and it forms the boundary be tween New York State and the Canadian Prov ince of Ontario. The volume of water which en ters Niagara is 280,000 cubic feet a second. In its upper course it is very wide (below Grand Island from 21..;; to 3 miles) ; just above Niagara Falls it is less than a mile in width, and below the falls it rushes headlong through a deep and narrow gorge to the cliff at Lewiston. where it emerges on the plain of Lake Ontario. and is again a broad and peaceful river.
As it emerges from Lake Erie and enters the plain, it is crossed by a low ridge of rock, in passing which the river is swift and troubled for about two miles. Then it is smooth again, flows slowly over the plateau, has an average depth of 25 feet, and its surface is interspersed with many small islands. For nearly three-fourths of its length it cannot he said to have a valley, for it flows upon the surface of the plateau, and its fall from the lake to the rapids above the cataract is only 20 feet. Then a sudden and complete change in its aspect occurs. It is dropped by the short rapids beginning a little above Goat Island 52 feet, which is the prelude to the fall over the majestic cataract, where it plunges 160 feet down into the plain, a total descent of 212 feet from the head of the rapids. At the foot of the American Falls there is no great depth of water. massive and broken rock in the bed having prevented the deep excavation that would otherwise occur; but the enormous mass of water, 20 feet deep at the centre and about nine-tenths of the whole volume, which thunders over the Canadian or Horseshoe Falls, has excavated a basin extending from shore to shore for 11:, miles below the falls that is fully as deep as the height of the falls. The effect
of this deep basin or reservoir is to retard and smooth the waters so far that rowboats cross the river and the little steamer Maid of the Mist is able to approach the cataract. The basin is succeeded by the narrow gorge which continues to Lewiston, its width rarely equaling one-fourth of a mile, and its depth to the bottom of the river varying from 200 to 501) feet. Its walls are so steep that they can he climbed only at a few places, and they reveal the geologic struc ture of the plateau—the bedded rocks of lime stone, shale, and sandstone lying almost hori zontally. The fall of the river in the gorge, seven miles long, is about 100 feet. The confined waters pour tumultuously along at an estimated speed of 30 miles an hour, and the terrific onrush and battle of the waters make a spectacle that is equal to that of the falls themselves. About midway in the gorge the channel makes an abrupt, short turn to the left, and here the onslaught of the torrent has worn out a vast circular basin forming the celebrated Whirlpool. From the Whirlpool the channel is broader and less steep. The plateau ends abruptly at Lewis ton, and its edge, where it. steeply descends to the littoral plain of Ontario, is marked by a long escarpment parallel with the shores of the lake, known to geologists as the Niagara Escarpment, which rises to about 250 feet above the level of Ontario. The last seven miles of the journey is over the littoral plain with a fall of only about three feet.
The position of Niagara Falls marks the pres ent extension of the work of the river in cutting this great gorge. It is not known by what chan nel or channels Lake Erie may have discharged its waters in pre-glacial times; but geologists have proved that the Niagara River began its existence during the final retreat of the great ice sheet ; in other words, most students of glacial geology agree that the history of the river covers only a small part of the period since the beginning of the age of lee.