DESTRUCTIVE EFFECTS OF WAVES. 29 



«till fartLer from 30 to 120 feet. A block nine feet two inches 

 by six feet and a half, and four feet thick, was hurried up the 

 acclivity to a distance of 150 feet." 



The great storm of 1824, which carried away part of the 

 breakwater at Plymouth, lifted huge masses of rock, from two 

 to five tonsin weight, from the bottom of the weatherside and 

 rolled them fairly to the top of the pile. One block of lime- 

 stone weighing seven tons was washed round the western ex- 

 tremity of the breakwater, and swept to a distance of 150 feet. 

 In 1807, during the erection of the Bell Rock lighthouse, six 

 large blocks of granite which had been landed on the reef were 

 removed by the force of the sea and thrown over a rising 

 lodge to the distance of twelve or fifteen paces, and an anchor 

 weighing about twenty-two hundredweight was cast upon the 

 surface of the rock. 



With such examples before our eyes, we cannot wonder that 

 in the course of centuries all shores exposed to the full shock 

 of the waves, lashing against them with every returning tide, 

 should gradually be wasted and worn away. One kind of stone 

 stands the brunt of the elements longer than another, but 

 ■ultimately even the hardest rock must yield to the rage of the 

 billows, which when provoked by wintry gales, batter against 

 them with all the force of artillery. 



Thus all along our coasts we find innumerable instances of 

 their destructive power. Tynemouth Castle now overhangs the 

 sea, although formerly separated from it by a strip of land, and 

 in the old maps of Yorkshire we find spots, now sandbanks in 

 the sea, marked as the ancient sites of the towns and villages 

 of Auburn, Hartburn, and Hyde. The cliffs of Norfolk and 

 Suffolk are subject to incessant and rapid decay. At Sherring- 

 haro Sir Gharles Lyell ascertained, in 1829, some facts which 

 throw light on the rate at which the sea gains upon the land. 

 There was then a depth of twenty feet (sufficient to float a 

 frigate) at one point in the harbour of that port, where only 

 forty-eight years ago there stood a cliff fifty feet high with 

 houses upon it 1 " If once in half a century," remarks the great 

 geologist, « an equal amount of change were produced suddenly 

 by the momentary shock of an earthquake, history would be 

 filled with records of such wonderful revolutions of the earth's 

 surface ; but if the conversion of high land into deep sea be 



