POPULAR GEOLOGY. 5 



single night. But there is another mysterious force ■which has never yet 

 been tlioroughly explained, which has acted a more important part in 

 upheaving continents, and keeping the equilibrium between land and sea, 

 than all the volcanoes and earthquakes that ever existed. We see the 

 effect, but cannot explain the cause; we only know that it is in some 

 manner connected with internal heat. ' The coasts of Norway afford an 

 interesting example of this silent force, which is known to be upheaving 

 that country and a great part of Sweden at the rate of four feet in a 

 century. South America and other parts of the world exhibit the same 

 phenomenon. The raised sea beaches of Scotland owe their origin to this 

 same force. In fact, the whole of Great Britain has been raised in this 

 manner out of the sea. While one part of a country is slowly rising from 

 beneath the waves, another part may be graduallj^ sinking below them, and 

 receiving an accession of strata. Thus, while one part of Sweden is 

 rising, another part is known to be sinking. Our own Yorkshu-e coast is 

 an example of these opposite movements. Many hamlets and villages along 

 the coast of Holderness have been destroyed within the memory of living 

 men, by the remorseless waves; and it has been calculated that more than 

 tAvo miles of coast have been thus destroyed by the sea during the last 

 1900 years; while, on the other hand, the neighbourhood of Hull has 

 received an increase of land called Sunk Island, and the area is con- 

 tinually being enlarged. How beautifully has Tennyson described the 

 strange mutations of land and sea — 



" There rolls the deep, where grew the tree. 

 Oh ! earth, what changes hast thou seen ! 

 1 here where the long street roars, hath been 

 1 he stillness of the central sea. 



The hills are shadows, and they flow 

 From form to form, and nothing stands ; 

 They melt like mists, the solid lands, 

 Like clouds they shape themselves and go " 



It might have been supposed before Geology was known, that the 

 various rocks which compose the crust of the earth were jumbled together 

 in a confused way, sandstone here, clay or shale there, limestone in one 

 place, and slate rock or granite in another, or all mixed together, as the 

 case might be — dropped down, as some learned men in olden times asserted, 

 by the tail of a comet. But Geology teaches us otherwise ; it shews us 



