Puddingstone

Puddingstone is a kind of sedimentary rock. It is formed when pebbles, perhaps from a shingle beach, are cemented together by silica coming out of solution.

The rock which forms is extremely hard and resistant to wear. It is used for grindstones and building. The pebbles are usually made of flint, and both they and the matrix are made of silica. These types of stones are also a source of million-year-old fossils.