Tidal Wave

Dune, or Sand Dune, a hill or ridge of sand deposited by the wind. Dunes form in areas where the wind blows most frequently in one direction at… See more » Valley, an elongated depression between bluffs, hills, or mountains. Small valleys surrounded by hills are often called hollows, glens, dales, or… See more » , the branch of knowledge that deals with the earth, its life, and its resources. The name comes from Greek and Latin words meaning “earth… See more »