Marble that isn't Marble

B and I had a day in Norwich today.  We completed a section of the River Walk and had a leisurely lunch in the beautiful Plantation Garden, which was a true oasis of calm hidden away from the traffic and bustle of the city.  While we were there we visited the huge Roman Catholic cathedral. It was constructed between 1882 and 1910 to designs by George Gilbert Scott Jr. as a parish church dedicated to John the Baptist, on the site of the Norwich City Gaol. The funds for its construction were provided by Henry Fitzalan-Howard, 5th Duke of Norfolk, as a gesture of thanksgiving for his first marriage to Lady Flora Abney-Hastings.  The outside of the cathedral is very difficult to photograph as it's rather hemmed in by other buildings so that's why I've chosen an interior shot.

The extra is a close-up of the beautiful Frosterley marble columns which feature throughout the cathedral.  Apparently it's not really marble but a polished limestone from the banks of the Wear River in County Durham.   It has white fossils running throughout produced from a tropical seabed some 325 million years ago.