The 'marble' is properly classified as a biomicrudite, as it consists of large clasts (the snail shells) in a fine-grained limestone mud matrix.
The outcrops lie within the Purbeck Monocline, with the beds dipping moderately steeply to the north.
During the Romano-British period, Purbeck Marble was used for inscriptions, architectural mouldings and veneers, mortars and pestles, and other articles.
[5] Purbeck Marble was also quarried in medieval times and can be seen in virtually all the cathedrals of the south of England, in columns and slab panels and flooring.
For example, it is used in Exeter, Ely, Norwich, Chichester, Salisbury, Lincoln, Llandaff, Southwark and Canterbury Cathedrals, and in Westminster Abbey.