Derryvree’s Frostbound Pool
The position of the Derryvree beds is itself important. They lie between tills: sediments laid down by glaciers or ice sheets. They show that, before a later advance overrode the district, freshwater conditions existed in at least this part of Fermanagh. The discovery overturns any simple picture of Ireland as continuously entombed beneath ice throughout the whole last glacial period. Instead, the island experienced shifting arrangements of ice, bare ground, periglacial terrain, lakes, marshes and drainage channels. Precisely how much of Ireland was ice-free at any particular moment around 31,844 BCE remains uncertain, because surviving deposits are rare and later ice repeatedly eroded or buried earlier landscapes.