118 THE WONDERS OF GEOLOGY. Lect. 1. 



60. Mutations in the relative level of land and 

 sea. — Of the reality of these changes in the relative level of 

 the land and of the Northern Ocean, there cannot exist a 

 doubt ; but the mind is so accustomed to associate the idea 

 of stability with the land, and of mutability with the sea, 

 that it may be necessary to offer a few additional remarks 

 on these highly interesting facts. As it is the property of 

 all fluids to find their own level, it is obvious that if the 

 level of the sea be elevated or depressed in any one part, 

 that elevation or depression must influence the whole 

 surface of the ocean, and the level therefore cannot be 

 affected by local causes. But movements of the land may 

 take place, and the effect extend over whole countries, as 

 in South America, — or along lines of coast, as in Sussex, 

 — or be confined to a single island, — or even to the area of 

 a temple, as at Puzzuoli.* 



But while the land is rising in the more northern 

 latitudes, it appears to be sinking on the shores of the 

 Mediterranean. Breislak mentions t that numerous re- 

 mains of buildings are to be seen in the Gulf of Baise ; ten 

 columns of granite, at the foot of Monte Nuovo, are nearly 

 covered by the sea, as are the ruins of a palace built by 

 Tiberius in the island of Caprea. Thus while the level of 

 the sea is becoming lower in the north, from the elevation 

 of the land, it is rising in the Mediterranean, from the 

 sinking of its coasts. Now, as all the parts of the ocean 

 communicate, the water cannot permanently rise in one part 

 and sink in another, but must rise and fall equally to main- 

 tain its level ; we must therefore consider it as demon- 

 strated, that these changes are solely dependent on the 

 elevation and depression of the land. If we bear in mind 

 the insignificance of the masses affected by these operations, 



* See Playfairs admirable commentary on this geological problem, 

 " Illustrations;' p. 433. 

 f Playfair. 



