Local Dalradian Limestone
There are several formations of limestone and meta-limestone inter-bedded with the Dalradian schists and psammites of the Sperrin Mountains these include the Alla Glen and Bond’s Glen Limestone within the Claudy Formation and Baranailt Limestone within the Ballykelly Formation.
The Dungiven Limestone Formation outcrops in Banagher Glen South of Dungiven where it used to be quarried and is distinctive with black calcite crystals of up to 1cm.
The Torr Head Limestone in County Antrim also forms part of the Dalradian Limestone in Northern Ireland.
All of these limestones are pale to dark blueish grey in colour and are not often used for building, they do occur on some buildings in Strabane, County Tyrone and Limavady, County Londonderry.