The Atlantic Ridge

In the Atlantic is found the biggest undersea mountain range in the world, called the Atlantic Ridge.

It begins near Iceland, and runs through the middle of the ocean as far south as the very tip of Africa. Then it turns east toward the Indian Ocean. Near the equator it is cut by a deep canyon, a "mountain pass," known as the Romanche Trench. Most parts of the ridge rise 5,000 to 10,000 feet above the sea bottom, and another mile or more of water covers most of the peaks. Some peaks rise out of the water, and these are islands. (Most sea islands are actually the peaks of underwater mountains.) Pico Island, in the Azores, is the highest point, rising 17,000 feet above the ocean floor, with 8,000 feet of its land above the water.

The shape, or contour, of the floor of the Atlantic has been very well charted. The laying of the first transatlantic cables, between 1850 and 1865, revealed many facts, including the existence of the Atlantic Ridge. With the discovery of echo-sounding and the deepsea camera, the story of the underseas landscape could be completed.

The deepest waters of the Atlantic (such ocean spots are called deeps, or trenches) are the Milwaukee Depth, near the Bahamas, found by the U . S . S . Milwaukee in 1939, which drops to 30,246 feet, and the Dolphin Deep, near Puerto Rico, which is 27,972 feet deep. Smaller seas of the Atlantic are Hudson and Baffin Bays, the Caribbean Sea, and the Gulf of Mexico, in the west; the North Sea, Baltic Sea, Bay of Biscay. Mediterranean Sea, and Gulf of Guinea, in the east.