The Book of the Ocean

by Ernest Ingersoll

The moment it had shores to beat upon, that moment the ocean began to knock them to pieces under its pounding surf, and to grind the fragments so small that they could be drifted away, reassorted, and deposited wherever the water was sufficiently quiet to let them fall. The original rocks—chiefly granite—held the different forms of lime, magnesia, etc., to make the limestones; the silica to make the gritty sandstones; the alumina to make the clays; and so on. The sea not only was the agent to eat this old, rich crust to pieces and respread it into strata, but to sort out for us the materials to a considerable extent, laying down beds of limestone by themselves, and sandstone, shales, marl, etc., by themselves. It is probable, says Professor Shaler, that layers of rock twenty miles in thickness have thus been laid down on the gradually settling ocean floor, much of which has been raised again to form continental lands.

Hitherto we have spoken of the waters that surround the continents as if they formed one mass, as, practically, they do; but for convenience sake we may designate certain areas by separate names, which ought now to be defined. Thus the larger, more open spaces are known as oceans, and of these five are recognized, namely, Pacific, Atlantic, Indian, Arctic, and Antarctic. Parts or branches of these, more or less inclosed by land and usually comparatively shallow, are termed seas.

The Pacific Ocean is the largest, it alone covering more space than all the continents combined, having a breadth, east and west, of ten thousand miles (about the length of the Atlantic), and an area of seventy million square miles. The equator divides it into the North and South Pacific. The former is comparatively free from islands, and is inclosed northward by the approaching extremities of Alaska and Siberia; while the latter widens at the south into the boundless Antarctic Ocean. Its basin is a vast depression of fairly uniform depth, studded in the western part by island peaks,—the summits of submerged volcanic mountain-ranges. The name “Pacific,” or “Peaceful,” was given to it by Magalhaens (Magellan), its first navigator, in 1540 [(see Chapter IV)], in his joy at having escaped from the tempestuous experience he had long endured in the South Atlantic. On the whole the Pacific deserves its name as compared with the Atlantic—a fact chiefly due to its great size. The term “South Sea” was formerly much used for it, but English-speaking persons now usually mean by that phrase the island-studded district between Hawaii and Australia.

PERCÉ ROCK, IN THE GULF OF ST. LAWRENCE, SHOWING DESTRUCTION OF SHORE-ROCKS BY WATER.

The Atlantic commemorates in its name the myth of Atlas and his island. Atlas seems to have been originally, among the Greeks, the name of the Peak of Tenerife, of which they had vague information from the earlier Phenician sea-wanderers. Then this was forgotten, and in place of the fact arose a myth of a Titan who stood upon a vast island in or beyond the “Western Sea,” called Atlantis. Legends of wars with its people form a part of the nebulous hero-story of the beginnings of Athens; and it is said to have sunk out of sight long before records began. There have always been those who believed this story founded upon fact, and only a few years ago a book was printed in the United States arguing that the tale was the history of a real land; but not only is there no literary or historical evidence that Atlantis had any firmer foundation than vague memories of the Cape Verd or Canary Islands, but every evidence of the geological condition and history of the eastern shores and bed of the middle Atlantic Ocean shows that no such convulsion as the destruction of this island calls for ever took place there, or that there was ever such a land to be submerged. The Atlantic occupies a long, winding, comparatively narrow trough, that measures about ten thousand miles north and south, from the ice of the Antarctic to the ice of the Arctic ocean, and has only a few islets south of Iceland, the Faroes and the Shetlands, which rise from a plateau stretching from Labrador to Great Britain, the higher points of which were probably above the water within comparatively recent geological times, possibly since man appeared upon the globe. The average depth of the Atlantic south of this ridge is about thirteen thousand feet, but greater depths are found along the African and American coasts, on each side of a long submerged ridge from which rise the isolated islands of Cape Verd, St. Helena, and Tristan da Cunha. The width from Norway to Greenland is only about eight hundred miles, but between Montevideo and Cape Town it is thirty-six hundred miles, and the average width is about three thousand miles. The shape and situation of the Atlantic make it the most stormy of the three great oceans, and it is the one where the phenomena of tides, currents, etc., are most prominently manifested, as we shall see. It is also the most frequented and best known, because it has been necessary to study it for the benefit of commerce.

The Indian Ocean is simply the extension of the vast southern water-zone northward of parallel 40°, south latitude, where, from the Cape of Good Hope to Tasmania, it is six thousand miles in width. At this line the depth suddenly decreases, as though the edge of a submerged Antarctic plateau defined the southerly rim of its basin there. This ocean contains several large and some groups of small islands, but these are mostly near the shore, and connected with the neighboring continent by shallow waters, showing that they rise from a submerged plateau. The average depth of the Indian Ocean is about fourteen thousand feet; its surface-water is warmer and salter than that of any other; and its winds and weather are more regular and peaceful than in either the Atlantic or the North Pacific.

The Arctic Ocean is the well-defined body of water around and probably over the north pole. It is connected with the Pacific only by the narrow and very shallow Bering Strait, and with the Atlantic by comparatively narrow openings. It has been fairly well explored as far north as the parallel of 80°, and found to contain many islands; but it appears that there is great depth of water north of Spitzbergen and northeast of Greenland, making it probable that the trough of the Atlantic reaches to or beyond the pole itself. Most of its area is covered with drifting ice.

The Antarctic Ocean is regarded as the space of water within the Antarctic circle; but this is surrounded by a zone of deep ocean, unbroken almost half-way to the equator, except by the narrow southern part of South America and by New Zealand. It is an area, apparently rather shallow, of ice, fogs, and tempestuous gales, inclosing lands of unknown extent.