The vast areas of swamps appeared a lot later as far as I know.
There could have been tribes each of a couple of hundred people in number wandering around these areas, areas that were not completely soaked with water, but areas that were still covered with forests and meadows and hills (as they discovered very recently by a study/mapping of the bottom of the North Sea).
Dutch and British trawlers have dragged up many stone tools from the bottom of the North Sea in their fishing nets, so maybe the area was not densely populated, but there were many more people living and hunting there than previously thought.
the ones who survived the raising of the north sea, did so by simple walking away.
Edited by danielost, 13 May 2010 - 08:02 PM.