PORTLAND ROACH (LARGE CUT SAMPLE) - Isle of Portland, Dorset

150 million years old (Late Jurassic)

Isle of Portland, Dorset

A cut sample of Portland stone showing cavities left by Jurassic fossil shells.

Portland stone is a world famous white limestone quarried on the Isle of Portland. The stone is an oolite that was first used by the Romans, but its most well-known use was by Christopher Wren for St. Paul’s Cathedral. There are 35 named quarries on the Isle of Portland, but only a few are still being worked.

The freestone beds are subdivided into the Base Bed, Whit Bed and Roach. The Roach Bed is the most distinctive as it has cavities that were created by the leaching out of fossil shells such as the gastropod Aptyxiella portlandica (known as the ‘Portland Screw’).