In this small quarry in the Dungiven Limestone Formation of the ancient Dalradian Supergroup, a bed of altered limestone about 4 m thick can be seen sandwiched between metamorphosed mudstones. It is the mineralization of this limestone by hot brine solutions circulating through the rock that provides the main interest. Pyrite (iron sulphide), chalcopyrite (copper iron sulphide), and galena (lead sulphide) occur in a 10 cm layer aligned with the bedding of the limestone. Veins of calcite up to 5 mm thick are also found, mostly in the joints of the limestone. Cubes of pyrite also occur within the limestone. Nothing is known of the age of the mineralization.
