Magnesian Limestone

Our first day in England we visited Hilton Castle in Sunderland and received a private tour, as my wife and brother in law are direct descendants of the Baron Hilton who built the castle.  Our tour guides were the former mayor of Sunderland and her husband.  Having an interest in construction I was curious about the stonework, in particular the type of stone that had been used to build the castle.  It was yellowish and mottled, almost as if with fossil impressions, which it was not.  The mortar joints were relatively large and some blocks had what appeared to be chisel marks on them.  Later I found out that this stone is called Magnesian limestone and occurs in a band from the area on the mouth of the river Wear to Nottingham in north-central England.  It is used in thousands of buildings in the area, including the oldest like Saint Peter’s church built in the Anglo Saxon period and the most complex like Durham cathedral built in the Norman period.

Not only was it the major component in many buildings, the coastline between the two rivers, the Tyne and the Wear, is made of it in cliffs about 50 feet high.  At the water’s edge are concretions called cannoball limestone and algae covered rocks also made of the same stone.