Sign inSHR, 1912
Handfast Point and the Old Harry Rocks shown in this photograph feature in many geography textbooks as an example of the stages of erosion of a headland.
This chalk headland, which formed with bands of flint about 66 million years ago, is being slowly eroded. The sea gradually works along the joints and bedding planes, where softer chalk meets harder bedrock, and enlarges them leaving behind stacks, wave-cut caves and notches in the base of the cliffs (sub-aerial weathering also plays a part in this process).
Old Harry, a sea stack, is slowly being removed by these coastal erosion processes and sub-aerial weathering. Another stump – called Old Harry’s wife – disappeared in 1509.
Student focus
- Why has the cliff been eroded at these specific points and not others? Which area is most prone to erosion and why?
- On a recent image of Old Harry Rocks, identify further changes. If none are visible, what does it tell you about the nature of this coast?
- These kinds of cliffs, caves and stacks often attract tourists – see slide 2. Use Digimap to identify where other named features are located around the British coastline and the BGS Geology of Britain Viewer find out what type of rock they are made of.
Current OS Explorer sheet: OL15