In pre-literate contexts, diverse knowledge was accumulated, processed and communicated orally. Recent research demonstrates that observations of memorable events were transferred in this way for sometimes thousands of years. Much of this information was eventually written down to reach literate audiences, which commonly judge such 'myths and legends' to be cultural inventions rather than ancient memories. This study examines 15 'submergence stories' from northwest European coasts and argues that they plausibly represent memories of postglacial sealevel rise which, in this region, was spatially and temporally variable owing to the interaction of sea-level rise with global isostatic adjustment. This study combines culture history and knowledge of earth rheology to argue that memories of the effects of postglacial land submergence in northwest Europe have endured for 5000-15,000 years. This requires a longevity of memory, orally communicated, that will surprise many. It also points to the likelihood that oral cultures in other parts of the world may have preserved observations of memorable events in a similar form that scientists today might benefit from trying to understand better.