[Fred Nerks]

...in post-glacial times, so it is assumed, in the Subboreal period, which began about 2000 years before the present era and endured to about 800 BC, large parts of the area were added to the sea. The Atlantic Ocean sent its waters along the Scottish and Norwegian shores, and also through the Channel that had been formed only a short while before. Human artifacts and bones of land animals were dredged from the bottom of the North Sea; and along the shores of Scotland and England, as well as the Dogger Bank in the middle of the sea, stumps of trees with their roots still in the ground were found...

Fortyfive miles from the coast, from a depth of thirty-six metres, Norfolk fishermen drew up a spearhead carved from the antler of a deer, embedded in a block of peat. This artifact dates from the Mesolithic or early Neolithic Age and serves as one of many proofs that the area covered by the North Sea was a place of human habitation not many thousands of years ago...

Earth In Upheaval. page 160.

Immanuel Velikovsky.

[SunkenCiv]

H. G. Wells discusses the former unity of Britain with the rest of Europe in his "History of the World". If memory serves. :')