Figure No. 4- Formation of Headlands and Bays

8.3.3. Cave, Arch and Stack

The processes of erosion by waves particularly hydraulic power and corrosion, convert any vertical line of weakness in rocks into caves. However, the rock needs to be relatively hard or resistant otherwise it will collapse before the cave is formed.

If the headland is subjected to erosion from two sides, the caves developing on either sides of the headland join to form a natural arch or sea arch. With time, continued erosion causes the arch to collapse, leaving an isolated vertical column of the rock, known as a stack, in front of

the cliff. In due course of time, the stack also gets eroded by the action of waves and it ends up in the form of a stump.

Figure No. 5-Coastal Erosional Features