Mammoth Cave’s Marked Femur
The best Irish environmental sequence relevant to this period was found at Derryvree, near Maguiresbridge in County Fermanagh. Road works in 1969 cut through a drumlin and exposed organic freshwater silts and fine sands lying between two separate sheets of till, the unsorted material deposited by glacier ice. The order of layers is direct evidence: ice had occupied the site; an interval followed in which freshwater and wet ground developed; later glacial action sealed the deposit beneath another till.