Celtic Shelf Horizons
Archived: 9 September 2026
Around 31,869 BCE, Ireland was a cold Late Pleistocene landscape, not a precisely datable historical moment. Before the Last Glacial Maximum, parts of the island remained ice-free, supporting open tundra wetlands, sedges, grasses, mosses and shallow freshwater habitats. Derryvree and Greenagho deposits in Fermanagh demonstrate these conditions, while cave evidence records climatic fluctuations and diverse fauna including mammoth, reindeer, giant deer, predators and smaller cold-adapted animals. Castlepook Cave suggests wider ecological links with north-west Europe, but its disturbed deposits limit precision. Human visits remain possible, yet no secure contemporary settlement exists. Expanding ice later reshaped and obscured much earlier evidence.