Oswald Bertram
Summer holiday, Lulworth, Dorset, England
This beach is famous to geologists because it is a good example of how different rock types erode. The arch is made of hard limestones so it is eroding very slowly. But the soft coloured clays in the middle of the picture are cut out very quickly by the waves, making the curved shape of the beach. And the chalk you see in the foreground forms hard wall at the back of the beach, which stops it from expanding too quickly, although there can be spectacular rock falls.
Here's more detail for anyone who is interested:
Summer holiday, Lulworth, Dorset, England
This beach is famous to geologists because it is a good example of how different rock types erode. The arch is made of hard limestones so it is eroding very slowly. But the soft coloured clays in the middle of the picture are cut out very quickly by the waves, making the curved shape of the beach. And the chalk you see in the foreground forms hard wall at the back of the beach, which stops it from expanding too quickly, although there can be spectacular rock falls.
Here's more detail for anyone who is interested: