Limestone wave-cut platform. This Langport blue lias formation was laid down in shallow seas 183-204 million years ago in the Jurassic and Triassic periods. After the deposits were formed stresses created the joints (fine cracks) in the limestone which have been widened by erosion. Alternate layers of soft mudstone shale and harder limestone are in horizontal beds which the sea has scoured away leaving a cliff and a flattish wave cut platform of limestone, the harder rock. Photographed at Lilstock beach, Somerset, UK.