Coastal land forms

The waves crash against the hard rock, eroding it with Hydraulic action, atrittion and Corrasion over time.

This causes Cracks and joints to form in the cliff face

The repeated erosion widens these cracks

which leads to......................

When the tide continues to erode the cracks in the cliff face, they are widened, eventually forming a cave. 

The tide will continue to erode and deepen the cave untill.......

An arch is formed! This is when the tide erodes the back of the cave completly.

The supports or pillars either side of the arch are eroded by the sea untill they become too weak to support the top of the arch, this means it collapses into the sea.

This leaves a...............

Stack! A stack stands alone, away from the headlands, like the Needles in the Isle of Wight.

The stack's base is continually eroded until it collapses leaving a..........

A stump is a broken/fallen stack and can be covered by the sea at high tide.

Arch:

Durdle's door, Dorset

Stack and stump:

Old Harry and Old Harry's wife, Dorset