MOST of the threatened North Wall at Glastonbury Abbey was built using rock rich in fossils from the Jurassic era.
The North Wall is one of three key areas in need of urgent conservation work and the focus of the Rescue our Ruins appeal launched by Glastonbury Abbey.
The appeal goal is to raise £500,000 to secure the ruins for future generations by funding conservation work and enhance the visitor experience to the abbey in The North Wall, The Lady Chapel, Crypt and Galilee and The Abbot’s Kitchen.
John Allan, the Abbey’s archaeological advisor, said: “Most of the North Wall is built of courses of a very rough local stone named ‘Tor burr’, the hard sandstone which forms the top of Glastonbury Tor.
“This rock is rich in fossils of the Jurassic era, especially belemnites (the internal skeletons of sea creatures similar to modern squid) and ammonites (similar to the modern nautilus).
“The use of this stone points to the antiquity of the wall, since Tor Burr was much used at the abbey in the Saxon and Norman periods but later fell out of favour; as the quality of masoncraft improved in the later Middle Ages the abbey and other local builders seem to have given up using this poor local rock, using instead higher-quality building stone brought from further afield.
“The soft brown mortar also points to a Norman date; later medieval masons produced much higher-quality lime mortars, and these usually appear brilliant white even today.”
The wall dates to the 12thcentury and is the oldest standing part of the abbey.
Mr Allan said: “Monasteries were usually enclosed with precinct walls, commonly 10 feet (about 3m) high. This wall, however, is far taller than would be needed simply to enclose the abbey; over most of its length it stands 5m high and would originally have risen to 6m (19 feet).”
He said closer inspection has revealed architectural features which indicate it was once a massive building, possibly a guest hall. Some of the blocks used above head height were quarried at the abbey’s manor of Doulting – 12 miles away.
Mr Allan added: “This wall, therefore, is an extraordinary survivor; it is probably the oldest standing part of the abbey ruins, predating the Lady Chapel and church, which were built after the great fire of 1186. Its great length leaves no doubt that it was once a mighty building. What was it?
“Perhaps the most likely interpretation is that this was a guest hall, designed to accommodate the throngs of visitors to the medieval abbey in a long open dormitory. Further more detailed inspection will no doubt reveal other features.”
Alan Thomas, the Abbey’s consultant architect, says: “Due to its exposed location and relatively weak construction, the wall has decayed significantly and the rubble surfaces and wall-head require careful conservation, stabilisation and additional protection to retain safety and to minimise further loss of fragile detail.”
Janet Bell, acting director and curator, said staff had been delighted by the response to the appeal to date.
She said: “The Abbey is close to the hearts of many in Glastonbury and further afield and the support we are receiving is encouraging.”