Erosion

Erosion, gradual wearing away of the land by natural forces. The main agents of erosion are weathering, running water, ice, winds, waves, and ocean currents. Natural erosion is an extremely slow process. For example, an average of 1 ft (0.3 m) of land is worn away from the surface of the United States every 900 years. But this rate is accelerated if the natural vegetation that covers and protects the surface is stripped away. Natural erosion is a continuous process, beginning as new land masses are uplifted and continuing until they are worn down.