Formation of Headland@

Headland is formed when there are alternate layers of more and less resistant rock. 

Formation of Geo

Because of wave refraction, wave energy concentrates on both sides of the headland. Erosion starts along the lines of weakness, e.g. joint or fault line. Hydraulic action and abrasion enlarge joints and produce sea caves. Continuous wave action makes the sea caves become larger and larger. The roof of sea cave will eventually collapse due to weathering and gravity. Geo is formed.