UPSC NDA II 2014 General Ability Paper

A cirque is an amphitheatre-like valley head, formed at the head of a valley glacier by erosion. Yardang is a keel-shaped crest or ridge of rock, formed by the action of the wind usually parallel to the prevailing winddirection. Barkhan is a crescent-shaped shifting sanddune convex on the windward side and steeper and concave on the leeward. It is an erosional feature of wind.Drumlin is a long, narrow or oval, smoothlyrounded hill of unstratified glacial drift. Drumlins are generally found in broad lowland regions, with their long axes roughly parallel to the path of glacial flow.