Caves, arches, stacks and stumps
Caves, arches, stacks and stumps are erosional features that are commonly found on a A high area of land that extends out into the sea..
- Cracks are formed in the headland through the erosional processes of hydraulic action and abrasion.
- As the waves continue to grind away at the crack, it begins to open up to form a cave.
- The cave becomes larger and eventually breaks through the headland to form an arch.
- The base of the arch continually becomes wider through further erosion, until its roof becomes too heavy and collapses into the sea. This leaves a stack (an isolated column of rock). An example of a Welsh stack can be found at Stack Rocks, Pembrokeshire.
- The stack is undercut at the base until it collapses to form a stump.
The Green Bridge of Wales in Pembrokeshire is a fantastic example of an arch