A sand dune that forms as a ridge parallel to the wind direction.

A long narrow sand dune that has its long dimension oriented parallel to the direction of the wind.

One of a series of long, narrow dunes lying parallel both to each other and to the prevailing wind direction. Longi-tudinal dunes range from 60 meters to 100 kilometers in length and from 3 to 50 meters in height.

An elongate sand dune oriented in the direction of the prevailing wind.

A dune formed when there is abundant sand and a strong, steady wind, and whose axis lies parallel to the wind direction.