Outer Belfast Lough ASSI

The site is important for the Ordovician seris of spilitic lavas, black shales and greywackes. The Carboniferous series of the Holywood group are also of significance and the Permian rocks are the best exposed series of rocks of this age in Ireland.

The habitat range includes open mud flats, boulder and rock shore, extensive mussel beds and a narrow shoreline strip of semi-natural vegetation including small, isolated pockets of beach-head saltmarsh.
Associated terrestial habitats are represented in a few places. Notable plants include spring squill and Ray's knotgrass.

Birds from Inner Belfast Lough ASSI regularly use Outer Belfast Lough for feeding, and the populations of the two areas are closely linked. However, in its own right, the area supports important numbers of great crested grebe and nationally important wintering populations of oystercatcher, ringed plover, redshank and turnstone.