This means you have to have hunter-gatherers hanging around the Mediterranean at about 9600 BC to observe events, and they have to be rowing out in canoes (if not Atlantean helicopters) in order to be familiar with the alleged drowned island, and then pass on the history through thousands of years of verbal tradition to the pre-dynastic ancient Egyptians, who can (much later) tell the Greeks. It's possible, but an alternative explanation is no.