Derryvree’s Buried Lakebed
Even with those cautions, Derryvree is exceptionally important. It shows that north-central Ireland was ice-free during a part of MIS 3 before the main expansion of the last Irish ice sheet. Plant and animal traces in the silts point to an open, treeless or almost treeless tundra landscape under periglacial conditions. Mosses and sparse herbaceous pollen survived where later ice would bury the old ground beneath till. The evidence does not provide a picturesque, complete view of the countryside: pollen was poorly preserved, and the proportions of plants in a deposit do not translate simply into a map. Yet it firmly rules out a wooded, temperate Ireland.