2 THE OCEAN. 



This is not simply a myth, it is a fact. The study of the strata of 

 the earth — rocks, sand, clay, chalk, conglomerates, proves that the 

 materials of the continental masses have in great part been deposited 

 at the bottom of the sea ; and have assumed their form and character 

 there. Many rocks, especially the granites of Scandinavia, which 

 were formerly believed to have emerged in a plastic state from the 

 interior of the earth, are perhaps in reality ancient sedimentary strata 

 slowly transformed by mechanical and chemical action, which operate 

 incessantly in the great laboratory of the globe. Even on the sides 

 and summits of the highest mountains, now raised thousands of feet 

 above the level of the ocean, may sometimes be found traces of the 

 action of the sea in ancient times. Under our very eyes the immense 

 work of creation, commenced by the seas in the earliest epoch, 

 is carried on without relaxation ; with such energy, in fact, that even, 

 during this short life, man may witness important changes along 

 their shores. If the waves undermine and slowly destroy a penin- 

 sula here, elsewhere they spread out sandy beaches and form islets. 

 New rocks, differing in arrangement and appearance, succeed the 

 ancient rocks demolished b}^ the waves. Thus the promontories of 

 granite are disintegrated by the action of the waters, which carry 

 away its various constituents, quartz, felspar, and mica, building 

 them up into new rocks. In the same way the clay resulting from 

 the slow decomposition of the porphyritic or granitic felspar is 

 transformed into slate, which becomes sooner or later as hard as the 

 ancient schists. But the dashing waves and the flowing rivers are 

 not the only agents occupied in the formation of new rocks in the 

 bosom of the sea. There is another ever active agent engaged 

 beneath its waters. This agent is animal life. Shells, corals, and 

 innumerable animalcula) with calcareous or silicious coverings, in- 

 habiting the ocean, are incessantly engaged in consuming and re- 

 producing. They absorb and digest matter which the rivers bring 

 down to the sea, and secrete substances which form their skeletons 

 and cases : as, generation after generation, these swarms perish, their 

 remains are spread out over the bottom of the sea or heaped up on 

 the strand ; and at last form immense banks and submarine plateaux 

 which by some subsequent elevation will be brought to light. 



Owing to this ceaseless renewal of the rocks, the ocean is constantly 

 creating a world differing from the old one in the appearance and the 

 disposition of its beds. Thus, to the geologist, the invisible depths 

 of the sea should not be of less importance than the exposed surface 

 of the continents. The ground which to-day bears us and our cities, 



