HO COAST CHANGES. 



limestone will project ; whereas if rocks much harder than lime- 

 stone are adjacent to the limestone, the latter will be worn away, 

 leaving the harder prominent. 



England is a country particularly favourable for a study of 

 this kind, both on account of its most varied rocks and on 

 account of its great length of seabord. Along the coast we 

 notice a very irregular outline ; and probably there is no other 

 part of the world which shows such a variety of rocks and such 

 a length of seabord for a comparatively small area. What are 

 the processes which cut the land back in the irregular form 

 which the coast presents ? The popular belief is that the sea 

 is cutting away the cliffs and wearing back the land. That is 

 poetry, not prose ; not the real fact. The sea really does little in 

 this way, except where the rocks are very hard and the sea 

 washes right up to them, and there it does undercut them. But 

 that is not so with soft rocks. On the majority of our cliffs 

 there are slips, and the cliffs- are worn away mostly not at the 

 bottom, but at the top. 



The two most familiar outlines of a cliff are what Ruskin has 

 described as the " wall above slope " and the " slope above wall." 

 The cliff is not worn away so much by the sea (except where 

 caves are hollowed out in the hard rock) as by the continuous 

 action of rain, frost, and sun, those changes in the weather that 

 cause alternate expansion and contraction, and thus lead to the 

 cracking of the rocks. The work of the sea is usually the work 

 of a carrier. The softer beds slip and fall down the slopes, and 

 the sea washes the material away as it is brought within its reach. 

 When the support of the upper beds is washed away there is 

 again a fall, and generally during heavy gales the lower talus is 

 swept away. 



Some coasts go very slowly. For example, on the Cornish 

 coast an old map shows nearly the same outline as at present ; 

 but if we come to our Dorset coast and compare the same old 

 map with the new six-inch ordnance map we can see that there is 

 hardly a place where some appreciable fraction of an inch of 

 the old map is not gone. It is important that these changes 



