Costal features

Coastlines do not always stay the same shape. As the sea pounds against the shore it gradually wears down the rock to form features such as caves and arches.
• if there is a crack in a cliff, seawater will get into it and gradually hollow out a cave.
• sometimes waves pound both sides of a headland and wear away an arch in the middle.
• Eventually arches collapse, leaving isolated rocks called stacks.
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• sometimes waves enlarge a cave so much that a crack appears in the roof. In rough weather water sprays out of the crack, called a blowholes.
In the ocean the water move away from the equator and cold water flowing in from polar regions to take its place.
• The world's largest current is the west wind drift, which flows between American and Antarctica.