The diagrams below depict a four-stage process in sequential erosion of the mountain range – Durdle Door in the city of Dorset, in the UK.
To begin, the destruction of the rock initiates with the weakest parts continuously remaining under the water. To be precise, vigorous waves cause the erosion that sufficiently affects the sloping rocky platform. As a result, the cave turns into an arch gradually expending in its diameter, forming a giant hole in the middle of the mountain range.
Following this, due to powerful water strikes touching the formed hole, it ultimately disappears and separates into an individual stack next to the headland. As it can be seen, the edge of the hill retreats after the separation of the eroded part, while the top of the stack commences to slightly crumble as it becomes converted into stumps at the surface of the water.
Overall, this is apparent that there is a natural tendency of water eroding the lower platform. Moreover, the process is likely to be constant, as there is an another arch following by the collapsed one.