The Atlantic Ocean
The most conspicuous topographical feature of the Atlantic is the mid-ocean ridge, a huge submerged mountain range surpassing is area the Alps an Himalayas combined.It runs down the middle of the ocean from Iceland in the north to a small island one thousand eight hundred meters off the coast of Antarctica in the south.The crest of the ridge marks the approximate middle of the Atlantic,and,with the exception of isolated areas near Iceland and near the Azores,the ocean floor at the crest has a mean depth of two thousand five hundred meters.The floor deepens gradually and systematically with increasing distance from the crest,reaching a maximum depth of between five thousand and six thousand meters before rising abruptly at the continental shelves.