CAVEMASTER DEMO PARTY
This is a large nodule of flint that formed around a lump of chalk which has since worn away. The result is a natural stone bowl (perhaps 20 inches across). It is probably too large to carry around.
Pot Stones are found mainly in parts of north-west Europe: Norfolk (United Kingdom), Ireland, Denmark, Basque Country and Germany. In Ireland a Pot Stone is called a Paramoudra.