Derryvree’s Ice-Free Silts
Derryvree is important because of its stratigraphy: layers of freshwater silt and organic sediment lay between older and younger tills, the unsorted deposits left directly by glacier ice. This sequence securely shows that, after one episode of glaciation and before another, the locality was free of overriding ice long enough for water, sediment, plants and insects to accumulate. The deposit is therefore a rare Irish witness to an interval of environmental change during the Middle Midlandian, the traditional Irish term for this part of the last glaciation.