Local Conglomerate

Drumarg Conglomerate from Armagh is the only example of conglomerate quarried for building stone in Northern Ireland. Most conglomerate occurs as random isolated quoins or blocks built with the local sandstones.

In County Antrim, Cushendall Conglomerate with clasts of welded tuff, schist and quartzite, is interbedded with sandstones and mudstones of the Devonian Cross Slieve Formation and used for building.

Pebble-rich beds also occur within the Fermanagh Carboniferous Sandstones (quartz pebbles or large greywacke clasts in the Topped Mountain Sandstone) and the Barony Glen Sandstone (with large rounded quartz pebbles).