Castlepook and Derryvree
Ireland was then part of the wider north-west European world of the last glacial cycle. It was not the uniformly ice-smothered island sometimes imagined from later phases of the Ice Age. The great British-Irish Ice Sheet would eventually expand dramatically, reaching its maximum extent on the Atlantic shelf roughly 26,000–24,000 cal BP and then retreating in stages. Around the equivalent of 31,901 BCE, however, evidence from beneath later glacial sediments indicates that at least some Irish regions had remained ice-free during earlier parts of the cycle. This does not mean that conditions were mild. It means that cold, seasonal and periglacial environments could exist beyond, between or before major ice advances.