Portland Admiralty Roach

File:PortlandRoach.jpg

Portland Admiralty Roach from a quarry face on the Isle of Portland, Dorset.

Portland Admiralty Roach is a kind of stone from the Isle of Portland used to construct "The Cobb", the well-known seawall at Lyme Regis in Dorset. The stone is rich in fossils (known as shells to local masons) often consisting of almost fifty percent fossilized remains with an average size of approximately 350 mm. The stone, which is still quarried by Albion Stone, has a maximum bed height of 2 metres. The stone is renowned for being highly frost resistant and being able to withstand the chemical effects of seawater.

See also

• List of stone
• List of types of limestone