Derryvree’s Sedge Marsh
Labelled 31,833 BCE, this period cannot be dated precisely in Ireland and is best understood as a Late Pleistocene interval within Marine Isotope Stage 3. Sediments at Derryvree and Greenagho show that parts of Ireland remained ice-free, supporting open tundra, sedge marshes and seasonal freshwater habitats before later glaciation. Castlepook Cave preserves remains of reindeer, mammoth and other cold-adapted fauna, although they do not represent a single community. A possible stone-tool cut on a reindeer bone suggests brief human activity, but no secure settlement evidence exists. Subsequent ice-sheet expansion reshaped Ireland, preserving Derryvree as a rare pre-glacial environmental record survival.