Castlepook’s Narrow Window
Archived: 20 September 2026
Around 33,000 calendar years before present, Ireland experienced increasingly severe, unstable conditions as the British-Irish Ice Sheet expanded towards its later maximum. Low sea levels allowed intermittent ecological connections, though routes remained uncertain. Derryvree, County Fermanagh, preserves freshwater evidence of treeless tundra wetlands supporting plants and insects. Castlepook Cave, County Cork, contains a disturbed assemblage including reindeer, mammoth, giant deer, hyaena, lemmings and Arctic fox, demonstrating repeated cold-adapted faunas. A possibly cut-marked reindeer femur may indicate brief Upper Palaeolithic human activity, but lacks secure context. No settlements, tools, institutions or continuous occupation can be established; erosion and glaciation obscured evidence.