Fermanagh’s Silt Interval
Archived: 9 September 2026
Around 31,868 BCE, Ireland lay in the unstable later Marine Isotope Stage 3, as the British–Irish Ice Sheet expanded unevenly. Derryvree, County Fermanagh, preserves freshwater silts between tills, recording an ice-free, sedge-rich tundra wetland later buried by advancing ice. Castlepook Cave, County Cork, contains a complex fauna including mammoth, giant deer, reindeer, predators and cold-adapted species, indicating productive open landscapes during favourable intervals. Butchery marks on a reindeer femur may represent Ireland’s earliest human activity, but cannot prove settlement or continuity. Changing climate, sea levels and ice margins made access and survival precarious. Evidence supports intermittent opportunity, not permanent occupation.
