372 



PHYSICAL GEOGRAPHY. 



much greater distance from its original site. At not less than three hundred miles from the 

 mouth of the Amazon, Captain Sabine found the sea discoloured by the waters of the 

 river, where they were still running with considerable rapidity ; but the stream does not 

 deposit its load of earthy material off its own estuary, for the great tropical oceanic 

 current westward crosses its course, takes up a part of its burden, bears it towards the 

 Caribbean Sea, and may even strew it over the bed of the Gulf of Mexico. In like 

 manner, the sedimentary matter which the mighty Mississippi discharges, and the rivers 

 of the United States east of the Alleghanies, is taken up by the majestic currents of the 

 gulf stream, and distributed over the floor of the North Atlantic. The whole extent of 

 our own eastern coast is annually deprived of a large mass of material by the tidal current 

 of the German Ocean. It undermines and sweeps away the granite, gneiss, trap rocks, 

 and sandstone of Shetland, and removes the gravel and loam of the cliffs of Holderness, 

 Norfolk, and Suffolk, which are between fifty and two hundred feet in height, and which 

 waste at the rate of from one to six yards annually. It bears away the strata of London 

 clay on the coast of Essex and Sheppy consumes the chalk with its flints for many 

 miles continuously on the shores of Kent and Sussex commits annual ravages on the 

 fresh-water beds, capped by a thick covering of chalk flints in Hampshire, and continually 

 saps the foundations of the Portland limestone. It receives, besides, during the rainy 

 months, large supplies of pebbles, sand, and mud, which numerous streams from the 

 Grampians, Cheviots, and other chains send down to the sea. To what regions is all 

 this matter consigned ? This question is no doubt answered in part by those immense 

 banks which are found along the coasts of England, Holland, and Denmark, and penetrate 

 to the central regions of the German Ocean, equal to about ^ of its whole area, or J of 

 the whole extent of Great Britain. There are thus formations proceeding upon a gigantic 

 scale, elevating and variously shaping the bed of the ocean, the result of the deposition 

 there of the. solid materials abraded from the land by the agency of rivers and sea-currents. 



The Valley of Chamouni after a Flood. 



It is easy to perceive, that should any upheaving cause expose to the gaze of man the 

 bottom of the existing seas, precisely similar phenomena would be exhibited to those 

 which the continents now present. Vast spaces of regular strata would appear, bearing 

 clear marks of having been formed by aqueous deposition, slowly and horizontally, 

 however inclined and fractured by the power of the elevating agent. 



