Nature reports (The megaflood that made Britain an island) that a team from Imperial College London have found strong evidence at the bottom of the English Channel that a major flood separated the British Isles from continental Europe.
Their survey reveals several distinctive features typical of large-scale flood flows, the team reports in Nature today. The straight shape of the wide underwater valley, a floor grooved and gouged as if by flowing water and tumbling rock, and streamlined 'islands' of raised sea-floor between deeper channels ...
They attribute this to an isolated incident: the breaking of a chalk ridge that dammed a huge lake to the North and East of Calais.
It would seem just as likely that this was just one part of the global catastrophe described in Genesis 6-8.