This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 Excerpt: ...to the sea. But even the outlet-stream of the lake, although usually more peaceable than the watercourse above, accomplishes its special geological labour, and is also employed in the task of doing away with the lacustrine basin. The water, impelled by its own weight, constantly wears away the layers which form the ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 Excerpt: ...to the sea. But even the outlet-stream of the lake, although usually more peaceable than the watercourse above, accomplishes its special geological labour, and is also employed in the task of doing away with the lacustrine basin. The water, impelled by its own weight, constantly wears away the layers which form the lower margin of the lake. The edge of this margin being gradually destroyed by the liquid mass, sinks by slow degrees, and the average level of the water in the lake sinks also in the same proportion. Thus, at the two extremities of the basin the river is carrying on two kinds of work, contrary in appearance, but which Fig. 122.--Filling Up Of A Lake-easin. Alluvium. have both an equivalent result in reducing the area of the lake which the river crosses. Up above, it gradually elevates its bed, and gains on the lake by filling it up with alluvium; down below, it lowers the brink, and, by this constantly increasing waste-gate, gradually drains out the water. The two stream-beds, the upper and the lower, will ultimately meet in the middle of the lake, and the latter will cease to exist. This is the double phenomenon which has been going on for ages in the Lake of Geneva. This crescent-shaped sheet of water certainly once extended as high up the stream as the place where the town of Bex now stands, 111 miles from the end of the lake; it also extended down the stream in narrow basins as far as Ecluse, 9 J miles from the outlet of the Rhone. It must, however, be understood that the outlets of lacustrine reservoirs are not the only places where the rapids and cataracts of a river crumble away the rocks so as to lower the up-stream and elevate the down-stream beds. However hard may be the strata which form the bed of a rapid, the eddying waters ultimate...
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