High and steep waves crash into the foot of the cliff, focusing their erosive capabilities into a small area.
A wave cut notch is created by undercutting the cliff:
Rock debris collects at the foot of the cliff and forms a terrace which is eventually moved into deeper water by backswash or along the beach by longshore drift.
The cliffs continue to retreat leaving behind a gently sloping (less than 5 degrees) wave cut platform.
This means that the waves break further out to sea and have to travel across more platform before reaching the cliff line.
This leads to a greater dissipation of wave energy which reduces the rate of erosion of the headland which slows the growth of the wave cut platform.