762 



HISTORY OF THE SEA. 



by the sea, and sandy beaches or promontories are built up 

 New rocks also, differing in appearance and constitution 

 from those worn away, are formed. But beside this action of 

 the sea upon the coasts, in constantly changing the configura- 

 tion of the land, modern observation has shown us that ani- 

 mal life is an agent constantly at work within the sea itself, 

 in the formation of new lands. The innumerable minute 

 forms of life with which the sea swarms ; the coral polyps, 

 lhe shells, the sponges, and the animalculae of all kinds, are 

 constantly engaged in consuming the food they find, in repro- 

 ducing themselves, and in dying. From the various matters 

 brought down to the ocean by the rivers of the land, they se- 

 3rete their shells or other coverings ; and as generation after 

 generation they die, these falling to the bottom form immense 

 banks, or plains, which some future action of upheaval will 

 bring above the surface to form the material for new conti 

 nents or islands. 



Thus while the ocean prepares the materials for the future 

 continents in its bosom, it also furnishes the waters which wash 

 away the lands already existing. To the thought of modern 

 science the granite peaks, the snow-clad mountains, immova- 

 ble and eternal as they seem, are constantly disintegrating, 

 and partake, with every thing else in creation, the eternal 

 round of change which is constantly going on. From the sea, 

 by evaporation, rise the vapors which, condensing against the 

 sides of the mountains, form the glaciers ; and these, slowly 

 sliding ^own toward the plains, are such efficient agents in 

 wearing away the mountains, grinding up their solid rocks 

 and preparing the gravel which the mountain streams distrib- 

 ute over the plains. From the sea the atmosphere receives 

 the moisture destined to return in rain from the clouds ; to feed 

 the brooks whose union forms the rivers, destined again to 

 return to the sea the waters it provided, and thus keep up, in a 

 gingle, mighty and endless circulation, the waters of the globe 



