Maguirebridge’s Moss-Rich Silt
“31,900 BCE” is a useful modern label, not a year that can be recovered from Ireland’s prehistoric record. No Irish calendar, written account, ruler, settlement sequence or human life can be assigned to that precise point. In radiocarbon and ice-sheet research, dates are normally expressed as ranges of calibrated years before present (cal BP, where “present” is AD 1950), often with sizeable uncertainty. In that convention, 31,900 BCE is roughly 33,850 years before present. It falls within Marine Isotope Stage 3 (MIS 3), a long and climatically unstable part of the last glacial cycle, and just before the great expansion of the British–Irish Ice Sheet that culminated several millennia later.