The Maguiresbridge Drumlin Fen
The strongest evidence for conditions in or near this period comes from Derryvree, beside Maguiresbridge in County Fermanagh. Road works in 1969 cut through a drumlin and revealed organic freshwater silts and fine sands trapped between two thick tills: deposits left by ice before and after the wetland existed. Organic material from the layer produced the conventional radiocarbon result Birm-166, 30,500 years BP, with a large uncertainty of +1,170/−1,030 years. Later work has expressed the possible calibrated age span broadly as c. 36,900–31,700 cal BP. The modern label 30,838 BCE falls within that range, but it is not possible to say that the Derryvree sediments accumulated in that particular calendar year.