The Maguiresbridge Freshwater Clock
Archived: 16 September 2026
Thirty-one thousand five hundred and eighty-three BCE is a label within Marine Isotope Stage 3, not a recoverable Irish year. At Derryvree, Maguiresbridge, freshwater silts between glacial tills, radiocarbon dated to 36,900–31,700 calibrated BP, show that north-central Ireland intermittently supported cold tundra wetlands, vegetation and animals before ice advance. Comparable deposits demonstrate fluctuating climates. Castlepook Cave preserves remains of mammoth, reindeer, giant deer, predators and cold-adapted fauna, although its mixed deposits cannot represent one moment. A marked reindeer femur may indicate early human butchery, but lacks context. Evidence confirms a dynamic glacial-edge landscape, not permanent settlement or a land bridge.