France: North Coast of France

Introduction

The north coast of France faces the English Channel (La Manche) and has a sequence of geological outcrops that is partly similar to those of the south coast of England. The Straits of Dover originated as a valley cut through the Chalk of the North Downs and the Calais district (Artois) by the combined Rhine and Thames rivers, which flowed westward. It has been widened during phases of marine submergence by the recession of the bordering Chalk cliffs as the result of wave erosion, and perhaps during low sea level phases of the Pleistocene by periglacial action. West of Cap Blanc Nez, the Chalk gives place to underlying formations across an anticline on the coast to Boulogne and Le Treport, matching the Weald between Folkestone and Eastbourne, and to the west, between Ault and Sainte Adresse, near Le Havre, the Chalk returns to the coast forming cliffs like those of the South Downs. There is no equivalent of the Hampshire Basin syncline, however, and the Baie de La Seine is...