Pas de Calais
South Foreland marks the south-western limit of St Margaret's Bay (named after the village of St Margaret's at Cliffe). It is the geological counterpart of Cap Blanc Nez ( cape white nose), at the northern extremity of the Boulonnais in the French "département" of Pas-de-Calais. The two are the landward ends of the fiercely cleft Strait of Dover land bridge and their chalk geological stratum dictates the route of the Channel Tunnel. Geologists have theorised that much of the erosion was river erosion from the extended Rhine and numerous southern North Sea channels discharging through the Strait of Dover.