Burton Bradstock

The cliffs here are made up of alternating layers of red sandstone and petrified mud. The sandstone is eroded much more quickly, partly by the sea, partly by water seeping down from the hinterland. The mudstone lasts much longer, with the result that these "shelves" reach out under the beach where the sandstone has eroded away. As the supporting sandstone is removed, the shelves collapse and are eventually broken up by wave action.