The Dungeon is a Site of Special Scientific Interest (SSSI) situated 1 mile north-west of Heswall, on the Wirral Peninsula, England. The site was notified in 1988 due to its geological features which show the Tarporley Siltstone Formation of the Mercia Mudstone Group. References Natural England citation sheet External links Metropolitan Borough of Wirral: The Dungeon (SSSI) Sites of Special Scientific Interest in Merseyside Sites of Special Scientific Interest notified in 1987