Mesolithic people under the sea

At www.dredgingtoday.com/2011/11/08/the-netherlands-archaeologists-find-hab… … during construction of new deep water port facilities in Rotterdam Dutch archaeologists have found Mesolithic remains – at a depth of 20m. During the early Holocene, before 6000BC, what is now Rotterdam was situated on the river bank of the Rhine and Maas. The southern North Sea was largely dry land – probably a bit marshy and with the occasional body of water but an environment that would have suited humans that lived by hunting fowl, fish and animals. Something dramatic happened to end this state of affairs.