BIRM-166 and Crag Cave
Archived: 17 September 2026
31,380 BCE is not a recoverable Irish historical year but a broad Late Pleistocene MIS 3 horizon. At Derryvree, County Fermanagh, organic deposits between glacial tills, including BIRM-166, indicate an ice-free interval with cold, open freshwater tundra environments, though radiocarbon calibration prevents precise dating. Crag Cave, Kerry, records milder episodes allowing calcite growth. Castlepook Cave, Cork, preserves diverse Ice Age fauna, demonstrating varied cold-climate ecosystems. A reportedly butchered reindeer bone may signal early human visitation, but remains disputed and cannot establish settlement or continuity. Subsequent expansion of the British–Irish Ice Sheet transformed and obscured this fragile environmental record in Ireland.