i6S PHYSIOGRAPHY. [chap. 



bring to bear upon the coast. Every wave carries, as it 

 were, a number of stone hammers, with which it bruises and 

 batters the cliffs ; and, as this action is persistently repeated 

 by wave after wave, the hardest rock is at length forced to 

 yield. 



Almost any part of our coast-line will serve to show the 

 destructive effects of the sea. It is true, the action is much 

 less marked in some directions than in others ; while, at 

 certain points, the sea may be engaged, not in destroying, 

 but in actually forming land, by deposition of sedimentary 

 matter resulting from the destruction of the shore elsewhere. 

 As a rule, however, abundant evidence of marine waste may 

 be seen on any visit to the seaside. Bays and coves may 

 be hollowed out in one part of the coast, and a headland 

 may be worn away in another : here, caves are being ex- 

 cavated in the base of a cliff; there, tunnels are drilled 

 through some projecting rock; while, in many places, wall- 

 like masses are partially detached from the cliffs so as to 

 stand out as buttresses, or are even completely isolated in 

 the form of "needles," "stacks," and "skerries." A good 

 example of marine denudation is furnished by the well- 

 known Needles off the Isle of Wight (Fig. 43). A ridge of 

 chalk runs across the island from east to west, and it is 

 evident that the outstanding wedge-shaped masses were 

 once connected with this main body, though now completely 

 surrounded by the sea. The headlands of chalk have been 

 beaten about by the waves until a passage has been forced 

 at a weak point, here and there ; and pillars of chalk have 

 thus been separated from the mainland. 



Where cliffs are formed partly of hard, and partly of soft, 

 rocks, the latter will naturally be more easily attacked by 

 the waves. The fantastic forms which sea-cliffs assume may 

 often be explained on this principle ; the harder beds, or 



