Yardang is a sharp irregular ridge of compact sand lying in the direction of the prevailing wind in exposed desert regions, formed by the wind erosion of adjacent material that is less resistant.
Barchan is a crescent - shaped shafting sand dunes, loess is an unstratified brown barry deposited by wind while self dunes are sand dunes in the form of a long narrow ridge
Yardang as to do with erosional land forms.