Appearance; It is a pillar structure of irregular surface with a minimum shape commonly found in deserts e.g Sahara desert.
Formation; Alternate beds of horizontal layers of hard and soft rock lying at right angle to the direction of the prevailing wind. It is a sand blasting caused by wind erosion.

Appearance: It is an isolated rocky out crop, with steep sides and round or flat top commonly found in semi arid or arid regions. It may rise up to a height of over 500 metres.
Formation; It is formed from an extensive old plateau. It is shaped by weathering and removal of weathered materials by water and wind