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 sand-banks 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 Sherringham, Sir Charles 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! "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 gradual, it excites only local attention." On the same coast, the ancient villages of Shipden, Wimpwell, and Eccles have disappeared, several manors and large portions of neighbouring parishes having gradually been swallowed up; nor has there been any intermission, from time immemorial, in the ravages of the sea along a line of coast twenty miles in length in which these places stood. Dunwich, once the most considerable sea-port on the coast of Suffolk, is now but a small village with about one hundred inhabitants. From the time of Edward the Confessor, the ocean has devoured, piece after piece, a monastery, seven churches, the high road, the town-hall, the gaol, and many other buildings. In the sixteenth century not one-fourth of the ancient town was left standing, yet, the inhabitants retreating inland, the name has been preserved,-- "Stat magni nominis umbra,"-- as has been the case with many other ports, when their ancient site has been blotted out. The Isle of Sheppey is subject to such rapid decay, that the church at Minster, now near the coast, is said to have been in the middle of the island fifty years ago, and it has been conjectured that at the present rate of destruction, the whole isle will be annihilated before the end of the century.