The diagrams Illustrate the process of erosion of a headland. It can clearly be seen that there are four main stages from the erosion of the lower part of the headland to the retreating of it.
To begin with, the vulnerable areas, especially the lower part of the headland, are eroded. It starts from a small hole to a bigger one. Eventually, it becomes a cave. Then, within the period, it becomes an arch. Durdle Door in Dorset is an example of this phenomenon.
Following this, water in a form of wave attack might occur on the coastal area, beating the roof of the arch. Then, it separated the cave from the main headland. Interestingly, a small part from an arch is called stack. As a result, the headland is retreating. The stack will continue to reduce in size, becoming a stump. At this time, the stump’s height is lower than water level. The whole process is a natural occurrence.