Prof. John Le Patourel, in "The Building of Castle Cornet" said that in 1566, iron and hammers were taken to "Creavissham", and the island quarried for the castle. The quarry has been used since then, but this has made the island much smaller, and less visible. As a result, a fifteen-foot () marker was built on the top. Crevichon may have provided the granite for the steps of St. Paul's Cathedral in London.