134 NATURAL HISTORY OF 



Sands; and the disappearance of the island was a natural con- 

 sequence of the tides acting upon its low shores, from the time 

 the Straits of Dover were opened, and the calamity an imme- 

 diate result of neglecting to defend the banks by artificial 

 means. The same force which swept away the town of Win- 

 chelsea, in the reign of Edward I., had long before destroyed 

 the Portus Iccius on the opposite coast, and commenced the 

 gradual denudation of the rocky basis of the Channel Islands, 

 where a tax is still levied and applied to arrest the further 

 encroachments of the sea. 



If tradition could be trusted, the present channel within the 

 Isle of Wight, was, in earlier ages, sufficiently shallow to be 

 forded at very low tides, where now line of battle ships pass in 

 safety; but this result is applicable to the whole British Chan- 

 nel, while Poole harbor is filled up by the deposits of slack 

 water. There is a marked character in the long succession of 

 landslips and "founders" in the vicinity of Lyme Kegis and 

 Azminster, resulting indeed from percolation to certain under- 

 lying strata, but, most assuredly, in connection with a progres- 

 sive erosion of the floor of the channel.* On the coasts of 

 Devon and Cornwall, numerous marks of ancient sea beaches, 

 hove up far beyond the present levels, indicate similar press- 

 ures and slidings of superincumbent strata, forcing the beach 

 to rise up in the same manner as occurred near Axminster. 

 St. Michael's Mount, however, is now almost severed from 

 Cornwall; and the invasion of the sea is still attested by the 

 remains of forest trees, sunk beneath the waters. 



Beyond the Land's End, the Scilly Islands, now forming a 

 cluster of rocks, were almost wholly united when first they 

 became historically known, under the name of Cassiterides. 

 In the Irish Channel, submersions, perhaps even greater than 



*If similar events in other countries were carefully recorded, they 

 would be found surprisingly numerous. Balbi, and Mr. G. Roberts, in 

 his account of the Dowland and Bindon landslip of 1339, enumerate a great 

 variety of them. 



