In the extreme north the French boundary includes a small part of the Anglo-Belgian basin. Coastal sand dunes protect the reclaimed marshes of French Flanders from invasion by the sea. The Alsace Plain
East of the Paris Basin is the Alsace Plain, bordered by the Vosges on the west, the Saône basin on the southwest, the Jura Mountains on the south, the Rhine River on the east, and Germany on the north. The terrace and foothills bordering the Rhine are covered with soil-enriching limon. Alluvial fans, which are laid down by tributaries emerging from the Vosges, and much of the floodplain of the Rhine and its major tributary, the Ill River, are forested. The Sundgau region of the Alsace Plain, which lies between the Jura and the Ill River above Mulhouse, is another great alluvial fan overlaying impermeable clays, which hold up numerous lakes. The Rhine River and its tributaries continue to deposit thick sediments on the floodplain. The river is canalized, to the considerable detriment of the water table on both sides. The Loire plains
Toward the southwest the Paris Basin opens on a group of plains that follow the Loire valley. The hills of this area, such as the limestone plateaus of the Touraine region and the crystalline plateaus of the Anjou and Vendée areas, are cut by the broad valleys of the Loire and its tributaries. The middle Loire valley, which varies in width from about 3 to 6 miles (about 5 to 10 km), is famous for its châteaus and its scenic beauty. The Aquitaine Basin
The Loire countryside links with the Aquitaine Basin of southwestern France through the gap known as the Gate of Poitou. The Aquitaine Basin is much smaller than the Paris Basin, and, while it is bounded in the south by the Pyrenees, in the northeast it runs into the low foothills of the Massif Central. The slopes of both the Pyrenees and the Massif Central decline toward the central valley of the Garonne River. The Aquitaine Basin lacks the clearly marked concentric relief of the Paris Basin. In the north it has limestone and marl plateaus cut by the fertile river valleys emerging from the Massif Central. The southern low plateaus were mostly filled by a mass of rather ill-defined Paleogene and Neogene sands and gravel called the molasse, stripped off the rising Pyrenees. The foot of the central Pyrenees is marked by a remarkable series of confluent alluvial fans forming the Lannemezan Plateau. The Landes, an area lying between the Garonne and Adour rivers to the west, has a surface that consists of fine sand underlain by impermeable iron pan, or bedrock. The area, once covered by heath and marshes, is now reclaimed and planted with maritime pine. South of the wide, deep Gironde estuary, the Bay of Biscay coast is lined by enormous sand dunes, behind which are shallow lagoons. The younger mountains and adjacent plains Pyrenees, Jura, and Alps
The Pyrenees, whose foothills shelter the picturesque Basque countryside, constitute the most ancient of the more recently formed mountains in France. They stretch for more than 280 miles (450 km), making a natural barrier between France and Spain. Their formation, which began in the Mesozoic Era (about 250 to 65 million years ago), continued in the Paleogene and Neogene periods and perhaps even in the beginning of the Quaternary Period (i.e., from about 2.6 million years ago). The central and highest part of the barrier is composed of a series of parallel chains with only a few, difficult-to-reach passes that have sheer drops at each end. A section of the mountain chain centring on Mont Perdu (Spanish: Monte Perdido) was named a UNESCO World Heritage site in 1997.
The Jura Mountains, extending into Switzerland, are composed of folded limestone. The northeastern part of the Jura, which has the most pronounced folding, is in Switzerland. The highest point, however, is Mount Neige (5,636 feet [1,718 metres]), in France.
The French Alps are only a part of the great chain that extends across Europe, but they include its highest point, Mont Blanc (15,771 feet [4,807 metres]). These majestic mountains were formed in a series of foldings during Paleogene and Neogene times. They include the two greatest regions of permanent snow and glaciers in Europe. The northern Alps are relatively easy to cross because of the numerous valleys created by the movement of glaciers. The relief of the southern Alps is much less orderly, and the valleys, which were not affected by glaciation, form narrow and winding gorges. Like the Pyrenees, the Alps form a natural barrier, dropping sharply down to the Po River plain in Italy. The southern plains
Between these young mountains and the ancient Massif Central is a series of plains, including those of the Saône and the Rhône rivers, which extend southward to the great triangular delta of the Rhône on the Mediterranean coast. Its seaward face, the Camargue region, comprises a series of lakes, marshes, and sand spits and includes one of Europe’s important wetland nature reserves. West of the Rhône delta the Languedoc coastal plain is broad and rather featureless; behind its sand-spit coast are several formerly mosquito-ridden lagoons, now part of a resort complex. At the southwestern end the foothills of the Pyrenees reach to the rocky coast of the Roussillon region. East of the Rhône delta the lowlands are more fragmentary; in the Côte d’Azur region the Alpine foothills and the ancient Maures and Esterel massifs reach to the Mediterranean, forming the coves, capes, and harbours of the country’s most famous tourist and retirement area, the French Riviera. Corsica is also highly regarded for its natural scenery. A number of the island’s peaks reach over 6,500 feet, and parts of it are under wild forest or covered with undergrowth called maquis.
The Mediterranean-washed pebble beach at Nice on the French Riviera.© Nedra Westwater/Black Star
Drainage
The river systems of France are determined by a major divide in the far eastern part of the country, running from the southern end of the Vosges down the eastern and southeastern edge of the Massif Central to the Noire Mountains, the southwestern promontory of the massif. This divide is broken by occasional cols (depressions) and lowland corridors, notably the Langres Plateau, across the Jurassic outer rim of the Paris Basin. Along the divide originate most of the rivers of the larger, western part of the country, including the Seine and the Loire. Other major rivers include the Garonne, originating in the Pyrenees, and the Rhône and the Rhine, originating in the Alps. The Seine system
Paris,
FranceThe Seine River
flows past
the
Île Saint-Louis
in
Paris,
France.Dana Hyde/Photo Researchers
Island in the Seine River near Les Andelys, France.© Pecold/FotoliaThe main river of the Paris Basin, the Seine, 485 miles (780 km) in length, is joined upstream on the left bank by its tributary the Yonne, on the right bank south of Paris by the Marne, and north of the city by the Oise. While the Seine has a regular flow throughout the year, there may be flooding in the spring and, occasionally more severely, during the customary fall-winter peak of lowland rivers. Efforts have been made to reduce flooding on the Seine and its tributaries by the building of reservoirs. A number of islands dot the Seine along its meandering, generally westward course across the central Paris Basin and through the capital city itself. One of these, the Île de la Cité, forms the very heart of the city of Paris. Eventually the river enters the English Channel at Le Havre.