Derryvree’s Silt Lens
Ireland was neither the familiar green island of later history nor necessarily a single unbroken white ice sheet. The climate was severe, seasonal and changeable. Ice had repeatedly advanced and retreated in the wider region, while local landscapes could differ greatly according to altitude, exposure, drainage and proximity to ice margins. The much more extensive Last Glacial Maximum lay ahead, conventionally placed broadly between about 27,000 and 20,000 years ago, although the growth and behaviour of Irish and British ice sectors remain subjects of active reconstruction.