With an uprise of 600 feet a vast plain would unite Britain to Denmark, Holland, and Belgium, and would present two platforms,[56] of which the more southerly would stretch from what are now the Straits of Dover northward to the northern edge of the Dogger Bank, where a steep declivity, doubtless a prolongation of the Jurassic and Cretaceous escarpments of Yorkshire, descends to the northern or lower platform. This submarine escarpment is trenched towards the west by a magnificent valley through which the united waters of the Rhine and Thames would flow, between the Dogger Bank and the Yorkshire cliffs. Another gap further east would allow the combined Elbe and Weser to escape into the northern plain. Possibly all these rivers would unite on that plain, but, in any case, they would fall into a noble fjord which would then be revealed following the trend of the southern coast line of Norway. Altogether an area more than thrice that of Britain would be added to Europe. By a total rise of 1800 feet, Britain would be united to the Faroe Islands and Iceland; while the Arctic and Atlantic Oceans would be separated. GEOLOGICAL CHARACTERISTICS OF BRITAIN. From its position on the oceanic border of a continent, Britain has been exposed to a great variety of geological change. In such a position marine erosion and deposit are most active. A slight upheaval or depression, which would have no sensible effect in the interior of a continent, makes all the difference between land and water on the coast-line. Moreover, there appears to be a tendency to special disturbance along the edge of an ocean. America affords the most marked proofs of this tendency, but in the structure of Scandinavia and its prolongation into Scotland and Ireland there appear to be traces of similar ancient ridging up of the oceanic border of Europe. There is a remarkable convergence of geological formations in Britain, each carrying with it its characteristic scenery. The rugged crystalline rocks of Norway reappear in the Scottish Highlands; the fertile chalk, with its smooth downs and gentle escarpment, stretches across to us from the north of France; the great plain of North Germany, strewn with the debris of the northern hills, extends into our eastern lowlands; even the volcanic plateaux of Iceland and Faroe are prolonged into the Inner Hebrides and the north of Ireland.