34 Denudation. 



sandstones cumber the sides of the hills and the bottoms 

 of the valleys in wild confusion (fig. 66, p. 329). In 

 Switzerland the relics of old landslips are often seen on 

 a magnificent scale ; and some of these, such as those of 

 the Eossberg, and St. Nicholas in the valley of Zermatt, 

 have taken place in the memory of living men. 



The constant atmospheric disintegration of cliffs, 

 and the beating of the waves on the shore, often aided 

 by landslips, is another mode by which watery action 

 denudes and cuts back rocks. This has been already 

 mentioned. Caverns, bays, and other indentations of 

 the coast, needle-shaped rocks standing out in the sea 

 from the main mass of a cliff, are all caused or aided 

 by the long-continued wasting power of the sea, which 

 first helps to destroy the land and then spreads the 

 ruins in new strata over its bottom. 



It requires a long process of geological education to 

 enable anyone thoroughly to realise the conception of 

 the vast amount of old denudations ; but when we con- 

 sider that, over and over again, strata thousands of 

 square miles in extent, and thousands of feet in thick- 

 ness, have been formed by the waste of older rocks, 

 equal in extent and bulk to the strata formed by their 

 waste, we begin to get an idea of the greatness of this 

 power. The mind is then more likely to realise the 

 vast amount of matter that has been swept away from 

 the surface of any country, in times comparatively 

 quite recent, before it has assumed its present form. 

 Without much forestalling the subject of a subsequent 

 chapter, I may now state that a notable example on a 

 grand scale may be seen, in the coal-fields of South 

 Wales, of Bristol, and of the Forest of Dean. These 

 three coal-fields were once united, but those of South 

 Wales and Dean Forest are now about twenty-five miles 



