Doggerland

Before the first glacial period of the current Pleistocene-Holocene Ice Age the Rhine river flowed northwards through the North Sea bed at a time when the North Sea was dry. It is thought that a Cenozoic silt deposit in East Anglia is the bed of an old course of the Rhine. The Weald was twice as long as it is now and stretched across the present Strait of Dover; the modern Boulonnais is a remnant of its east end.

With glaciation, when Scandinavian and Scottish ice first met and formed a giant ice dam, a large proglacial lake then formed behind it, which received the river drainage and ice melt from much of northern Europe and Baltic drainage through the Baltic River System. The impounded water eventually overflowed over the Weald into the English Channel and cut a deep gap which sea erosion later widened gradually into the Strait of Dover.

During the most recent glaciation, the Devensian glaciation which occurred around 10,000 years ago, the North Sea and almost all of the British Isles were covered with glacial ice and the sea level was about 120 metres (390 ft) lower than it is today. Much of the North Sea and English Channel was an expanse of low-lying tundra, extending around 12,000BC as far as the modern northern point of Scotland.[4]

Evidence including the contours of the present seabed shows that after the first main Ice Age the watershed between North Sea drainage and English Channel drainage extended east from East Anglia then southeast to the Hook of Holland, not across the Strait of Dover, and that the Thames, Meuse, Scheldt and Rhine rivers joined and flowed along the English Channel dry bed as a wide slow river which at times flowed far before reaching the Atlantic Ocean.[4][3] At about 8,000BC, the north-facing coastal area, now called Doggerland, had a coastline of lagoons, marshes, mudflats, and beaches. It may have been the richest hunting, fowling and fishing ground in Europe available to the Mesolithic culture of the time.[3][5]