To Dublin Bay; the Boyne, fed from the central plain and discharging into Drogheda Bay; from the mountains of county Down, the Lagan, to Belfast Lough, and the Bann, draining the great Lough Neagh to the northern sea; the Foyle, a collection of streams from the mountains of Tyrone and Donegal, flowing north to Lough Foyle.
The great difference in character, however, between the Silurian strata at Pomeroy in county Tyrone and the adjacent metamorphic series makes it highly probable that the latter masses are truly Archean.
The axis along which they have been elevated runs north-east and south-west, and on either flank a series of " green rocks " appears, consisting of altered amygdaloidal andesitic lavas, intrusive dolerites, coarse gabbros and diorites, and at Beagh-beg and Creggan in central Tyrone ancient rhyolitic tuffs.
In the districts of the Old and New Red Sandstone, which include the greater part of Cork and portions of Kerry, Waterford, Tyrone, Fermanagh, Monaghan, Mayo and Tipperary, the soil in the hollows is generally remarkably fertile.
Peter and Mark (Khoda Mustapha Jamissi at Aivan Serai), St Theodosia (Gul Jamissi), St Theodore Tyrone (Kilisse Jamissi).