Page:Early Man in Britain and His Place in the Tertiary Period.djvu/179

] From these lines of reasoning it may be concluded that Britain stood at least 600 feet above its present level, and that the rivers of our eastern coast, the Thames, Medway, Humber, Tyne, and others, joined the Rhine, the Weser, and the Elbe, to form a river flowing through the valley of the German Ocean, as represented in the map. In like manner, the rivers of the south of England, and of the north of France, formed a great river flowing past the Channel Islands due west into the Atlantic, and the Severn united with the rivers of the south of Ireland; while those to the east of Ireland joined the Dee, Mersey, Kibble, and Lune, as well as those of western Scotland, ultimately reaching the Atlantic to the west of the Hebrides. The watershed between the valleys of the British Channel and hethe [sic] North Sea is represented by a ridge passing due south from Folkestone to Dieppe, and that between the drainage area of the Severn and its tributaries on the one hand, and of the Irish Channel on the other, by a ridge from Holyhead westward to Dublin.

This tract of low undulating land which surrounded Britain and Ireland on every side consisted not merely of rich hill, valley, and plain, but also of marsh land studded with lakes, like the meres of Norfolk, now indicated by the deeper soundings. These lakes were very numerous to the south of the Isle of Wight, and off the coast of Norfolk and Suffolk.