Petworth marble

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Pet´worth mar´ble

1.A kind of shell marble occurring in the Wealden clay at Petworth, in Sussex, England; - called also Sussex marble.
References in periodicals archive ?
53) Widely used since Roman times for interior monuments, including those at Canterbury Cathedral, Petworth marble is "easily weathered by acid rain," which dissolves the matrix and allows the shells to fall out.
For the shells' resemblance to the modern "periwinkle," Petworth marble and the related Purbeck stone are sometimes colloquially called "winklestone.