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flows, and that the propelling force of its waters is not now, and 

 never could have been, adequate to the transport of the boulders 

 which lie scattered on the sides and summits of the chains of hills 

 through which it has found a passage: that much of the waterworn 

 gravel, drifted through the breaches opened in the sinuous line of 

 its channel, is composed of rocks not found within the limits of its 

 basin ; and that the form of the country is often the very reverse 

 of that which would have been produced by mere fluviatile erosion, 

 however long continued. Similar facts are supplied by nearly all 

 the greater valleys of England ; and on the whole they point to 

 one conclusion, that fluviatile erosion, as a mere solitary agent, 

 has produced but small effects in modifying the prominent features 

 of our island : at the same time they leave untouched all the facts 

 of an opposite kind, supported by direct evidence, whether de- 

 rived from the volcanic districts of Central France, or from any 

 other physical region on the surface of the earth. 



The power of mountain torrents in transporting heavy masses of 

 stone is strikingly illustrated in a short paper by Mr. Culley. He 

 states that a small rivulet, descending from the Cheviot Hills along 

 a moderate declivity, carried down, during a single flood, many 

 thousand tons of gravel into the plains below; and that several 

 blocks, from one-half to three-quarters of a ton weight each, were 

 propelled two miles in the direction of the stream. Facts, similar 

 in kind, but on a scale incomparably greater, must be in the recol- 

 lection of every one who has seen the Alpine torrents descending 

 into the plains of the north of Italy. 



When mountain chains abut in the sea, the laws of degradation 

 are not suspended. At each successive flood, fragments of rock 

 are drifted in the direction of the descending torrents, and rolled 

 beneath the waters. This kind of action is indeed casual and in- 

 terrupted ; but it is aided by another action which is liable to no 

 intermission — the beating of the surf and the grinding of the tidal 

 currents on all the projecting parts of a steep and rocky shore. 

 Under such conditions, I doubt not that there are now forming at 

 the bottom of the sea, and at depths perhaps inaccessible, alter- 

 nating masses of silt, and sand, and gravel, which, if ever lifted 

 above the waters, may rival in magnitude some of the conglomerates 

 of our older formations. 



Our last Paper, on the excavating power of rivers, was from the 

 pen of Mr. Scrope. He contends that diluvial torrents would only 

 form trough-shaped channels prolonged in the direction of the 

 principal rush of water ; but would never produce curves in which 

 the excavating force worked in a direction opposed to that of the 

 general current. He describes part of the course of the Moselle 

 and of the Meuse, where the rivers wind through hard transition 

 rocks, in long sinuous channels, varying in depth from 500 to 1000 

 feet. In one of the great flexures of the Moselle, the river, after 

 passing over no less than 17 miles, returns to within 500 yards of 

 the point from which it started. These phenomena are regarded 

 by the Author as sure indications of slow fluviatile erosion. For he 



