BIRM-166 Organic Horizon
Archived: 27 September 2026
Thirty thousand five hundred and seventy-five BCE is a modern label within a broad calibrated range, not a recoverable prehistoric year. At Derryvree, County Fermanagh, the BIRM-166 organic horizon records a cold, freshwater wetland formed during an ice-free interval between glacial advances in Marine Isotope Stage 3. Plant, insect and animal evidence indicates open, treeless periglacial conditions. Cave faunas in southern Ireland show that large mammals and predators occurred regionally, though not necessarily together or contemporaneously. No secure evidence confirms human settlement, agriculture, trade, religion or political organisation. Later glaciation destroyed or altered much evidence, making cautious reconstruction essential there.