Birm-166’s Permafrost Ledger
Archived: 14 September 2026
Abstract
31,762 BCE is not a knowable Irish year but a broad Late Pleistocene horizon. Derryvree, County Fermanagh, dated through Birm-166, preserves freshwater silts, plants and small animals from roughly 36,900–31,700 years ago, indicating cold, open tundra and periglacial conditions before the ice sheet's maximum expansion. Castlepook Cave, County Cork, contains mixed remains of mammoth, reindeer, giant deer, bears, hyenas and other fauna, proving episodic animal access. A cut-marked reindeer femur may indicate human butchery, but neither permanent settlement nor associated tools are established. No polities, farming, trade or recoverable culture are evidenced; later ice obscured much of this fragile record.