THE LAND
France is composed of a number of
distinctive natural units, many of which have a complicated geologic history and form a
pattern of great variety. The country's landscapes vary from flat, almost featureless
plains to Mont Blanc, which spreads across the border of France and Italy, rising to
15,771 feet (4,807 meters) in the glorious French Alps.
Northern France, particularly the
region of Ile-de-France and its margins, is dominated by the Paris Basin. This vast
surface, which appears very flat in many places, has been compared to a series of saucers
of decreasing size stacked one inside the other. There are gently sloping surfaces toward
the interior, and steep slopes on the outer edges. Paris is in the center of the basin,
and the outward-facing ridges, composed primarily of resistant limestone, have
historically provided strong defensive lines to the east. The ridges form rugged chalk
cliffs along the English Channel to the west. To the north, the Paris Basin blends into
the plains of Flanders and northwestern Europe. The Ardennes and Vosges mountains to the
northeast and east are part of a zone extending beyond the Rhine River through central
Germany.
To the west, much older rocks,
mainly granites and schists, form the Massif Armoricain of Brittany and the Cotentin
Peninsula of Normandy. In the southwest, the Paris Basin is connected by a low threshold,
called the Gate of Poitou, to the other large lowland region in France, the Aquitaine
Basin. Along the Bay of Biscay, Aquitaine has many areas of sandy soil and some of
France's flattest surfaces. The south-central part of France is dominated by a large area
of uplands, mostly of volcanic origin, known as the Massif Central and including the
regions of Limousin and Auvergne. This area is dotted with peaks rising from 4,000 to
6,000 feet (1,200 to 1,800 meters), which impede communications and economic activity.