WATER AS A MECHANIC AL AGENT. 



219 



The cliffs of iSTorfolk and Suffolk, England, afford an example of seashore 

 encroachment that has long been nnder observation as the country is one 

 of houses and cultivated fields. Lyell states that in 1805, when an inn at 

 Sherringham was built, it was 50 yards from the sea, and it was computed 

 that it would require 70 years for the sea to reach the spot — the mean 

 loss of land having been calculated, from former experience, to be somewhat 

 less than one yard annually. But it was not considered that the slope of 

 the ground was from the sea. Between the years 1824 and 1829, 17 yards 

 were swept away, bringing the waters to the foot of the garden ; and in 1829 



190. 



Rock detached by wave-action, Otter Creek, Mount Desert, Me. Shaler, '89. 



there was depth enough for a frigate, 20 feet, at a spot where a cliff of 50 

 feet stood 48 years before. Farther to the south, the ancient villages of 

 Shipden, Wimpwell, and Eccles have disappeared. This encroachment of 

 the sea has been going on from time immemorial. 



3. Limit of wave-denudation ; Planation. — Besides battering and degrad- 



