Parna is an Australian term used in the United States for dunes made of clay and silt, which are commonly found in the Great Basin. The related term lunette refers to a crescent-shaped parna, which often forms on the downwind perimeter of rainwater, or playa, lakes in the Texas panhandle. These formations are created by the motion of the wind, but unlike sand dunes, they are a textured mass of material and, though fragile, give the appearance of solidity.

Susan Brind Morrow