 At the height of the last ice age, around 20,000 BC, Britain was connected to mainland Europe by a large expanse of land known as Doggerland in the southern North Sea Basin.At this time, the Thames' course did not continue to Doggerland but flowed southwards from the eastern Essex coast where it met the waters of the proto-Rhine, -Meuse and -Scheldt flowing from what are now the Netherlands and Belgium.These rivers formed a single river – the Channel River ("Fleuve Manche") – that passed through the Dover Strait and drained into the Atlantic Ocean in the western English Channel.