Barony Glen Sandstone
The sandstone used as building stone in this area (often referred to as ‘Dungiven Sandstone’ in historical literature) is of the Carboniferous Sandstone and Conglomerate Formation (Roe Valley Group) which was formed around 350 million years ago. It was used widely in the 19th Century, through this region and is recorded as being used on many buildings in Derry City including the Guild Hall.
The Roe Valley Group (Barony Glen Formation and Inishcarn Formation) crops out on the West side of White Mountain and Mullaghmore and along the South side of Lough Foyle. A range of large quarries were once operational in and around Altmover Glen, just outside Dungiven and these are now all disused and overgrown. Both Barony Glen and Inishcarn Formations also crop out in the Draperstown area and the sandstone was known to be quarried at the Forge Bridge Quarry near Draperstown.
The Barony Glen Sandstone used as building stone in this area is very variable although sandstone from the quarries near Dungiven and those near Draperstown are sometimes distinguishable. The stone has a vast range of colours buff, white, yellow to pink. Individual blocks can be uniform in colour and texture or exhibit a variety of hues and bedding. Individual pebbles and beds of coarser material are often visible in blocks.
The sandstone from this area performs well as a building stone in rural areas. Stone faces generally show granular disintegration, differential weathering along bedding planes and occasional pitting of stone surfaces