Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/154



occupies a great part of the baronies of Ardes, Castlereagh, and the two Iveaghs in the north of the county of Down, whence they extend through Armagh and Monaghan into Cavan. The accompanying map (Pl. 8.) will convey a sufficiently accurate idea of their extent. Their characters do not differ from those which they exhibit in other countries already frequently described.

The greywacke slate is worked extensively for rooting slate at Ballyalwood in the center of the peninsula of Ardes: a variety however, still better adapted to this purpose, remains yet neglected at Cairn Garva, on the west-south-west of Conbigg hill.

At Cultra, on the north-east of Belfast lough, Binty slate and drawing slate occur as subordinate formations in the greywacke.

Lead and copper ores have been found in this formation at Conbigg hill, between Newtown Ards, and Bangor, and I believe at some other places. A mine was formerly worked at Conbigg, but is now abandoned.