The Ring of Gullion, an igneous, intrusive, granitic rock, dominates the south-east portion of this map.  What is perhaps more remarkable is the Newry Granite [white] that has intruded into the centre of the Ring!

The North of Co Armagh, bordering Lough Neagh, is dominated by estuarine clay [tan].  This owes its origin to successive Ice Ages, but mainly the most recent.  The melted glacier that dominated the landscape there left the Lough when it melted and created the overflow drainage channel that now constitutes the route of the Newry Canal. 

All other rock types here are sedimentary [the only metamorphic rocks in North Ireland are the schists of the Sperrins and Donegal gneisses] and were created over hundreds of millions of years, when this land was south of the equator and much of it submerged beneath equatorial oceans.  The terms Ordovician [green] Tertiary [blue] Silurian [lime] etc. refer to periods of Earth History. 

Apologies for the roughness of the drawn map:  I only had children's crayons to work with!!

---