France is geographically remarkable for its possession of great natural and historical highways between the Mediterranean and the Atlantic Ocean. The one, following the depression between the central plateau and the eastern mountains by way of the valleys of the Rhône and Saône, traverses the Côte d’Or hills and so gains the valley of the Seine; the other, skirting the southern base of the Cévennes, reaches the ocean by way of the Garonne valley. Another natural highway, traversing the lowlands to the west of the central plateau, unites the Seine basin with that of the Garonne.
Physiography.—A line drawn from Bayonne through Agen, Poitiers, Troyes, Reims and Valenciennes divides the country roughly into two dissimilar physical regions—to the west and north-west a country of plains and low plateaus; in the centre, east and south-east a country of mountains and high plateaus with a minimum elevation of 650 ft. To the west of this line the only highlands of importance are the granitic plateaus of Brittany and the hills of Normandy and Perche, which, uniting with the plateau of Beauce, separate the basins of the Seine and Loire. The highest elevations of these ranges do not exceed 1400 ft. The configuration of the region east of the dividing line is widely different. Its most striking feature is the mountainous and eruptive area known as the Massif Central, which covers south-central France. The central point of this huge tract is formed by the mountains of Auvergne comprising the group of Cantal, where the Plomb du Cantal attains 6096 ft., and that of Mont Dore, containing the Puy de Sancy (6188 ft.), the culminating point of the Massif, and to the north the lesser elevations of the Monts Dôme. On the west the downward slope is gradual by way of lofty plateaus to the heights of Limousin and Marche and the table-land of Quercy, thence to the plains of Poitou, Angoumois and Guienne. On the east only river valleys divide the Auvergne mountains from those of Forez and Margeride, western spurs of the Cévennes. On the south the Aubrac mountains and the barren plateaus known as the Causses intervene between them and the Cévennes. The main range of the Cévennes (highest point Mont Lozère, 5584 ft.) sweeps in a wide curve from the granitic table-land of Morvan in the north along the right banks of the Saône and Rhône to the Montagne Noire in the south, where it is separated from the Pyrenean system by the river Aude. On the south-western border of France the Pyrenees include several peaks over 10,000 ft. within French territory; the highest elevation therein, the Vignemale, in the centre of the range, reaches 10,820 ft. On the north their most noteworthy offshoots are, in the centre, the plateau of Lannemezan from which rivers radiate fanwise to join the Adour and Garonne; and in the east the Corbière. On the south-eastern frontier the French Alps, which include Mont Blanc (15,800 ft.), and, more to the south, other summits over 11,000 ft. in height, cover Savoy and most of Dauphiné and Provence, that is to say, nearly the whole of France to the south and east of the Rhône. North of that river the parallel chains of the Jura form an arc of a circle with its convexity towards the north-west. In the southern and most elevated portion of the range there are several summits exceeding 5500 ft. Separated from the Jura by the defile of Belfort (Trouée de Belfort) the Vosges extend northward parallel to the course of the Rhine. Their culminating points in French territory, the Ballon d’Alsace and the Höhneck in the southern portion of the chain, reach 4100 ft. and 4480 ft. The Vosges are buttressed on the west by the Faucilles, which curve southwards to meet the plateau of Langres, and by the plateaus of Haute-Marne, united to the Ardennes on the north-eastern frontier by the wooded highlands of Argonne.
Seaboard.—The shore of the Mediterranean encircling the Gulf of the Lion (Golfe du Lion)[2] from Cape Cerbera to Martigues is low-lying and unbroken, and characterized chiefly by lagoons separated from the sea by sand-dunes. The coast, constantly encroaching on the sea by reason of the alluvium washed down by the rivers of the Pyrenees and Cévennes, is without important harbours saving that of Cette, itself continually invaded by the sand. East of Martigues the coast is rocky and of greater altitude, and is broken by projecting capes (Couronne, Croisette, Sicié, the peninsula of Giens and Cape Antibes), and by deep gulfs forming secure roadsteads such as those of Marseilles, which has the chief port in France, Toulon, with its great naval harbour, and Hyères, to which may be added the Gulf of St Tropez.
Along the Atlantic coast from the mouth of the Adour to the estuary of the Gironde there stretches a monotonous line of sand-dunes bordered by lagoons on the land side, but towards the sea harbourless and unbroken save for the Bay of Arcachon. To the north as far as the rocky point of St Gildas, sheltering the mouth of the Loire, the shore, often occupied by salt marshes (marshes of Poitou and Brittany), is low-lying and hollowed by deep bays sheltered by large islands, those of Oléron and Ré lying opposite the ports of Rochefort and La Rochelle, while Noirmoutier closes the Bay of Bourgneuf.
Beyond the Loire estuary, on the north shore of which is the port of St Nazaire, the peninsula of Brittany projects into the ocean and here begins the most rugged, wild and broken portion of the French seaboard; the chief of innumerable indentations are, on the south the Gulf of Morbihan, which opens into a bay protected to the west by the narrow peninsula of Quiberon, the Bay of Lorient with the port of Lorient, and the Bay of Concarneau; on the west the dangerous Bay of Audierne and the Bay of Douarnenez separated from the spacious roadstead of Brest, with its important naval port, by the peninsula of Crozon, and forming with it a great indentation sheltered by Cape St Mathieu on the north and by Cape Raz on the south; on the north, opening into the English Channel, the Morlaix roads, the Bay of St Brieuc, the estuary of the Rance, with the port of St Malo and the Bay of St Michel. Numerous small archipelagoes and islands, of which the chief are Belle Île, Groix and Ushant, fringe the Breton coast. North of the Bay of St Michel the peninsula of Cotentin, terminating in the promontories of Hague and Barfleur, juts north into the English Channel and closes the bay of the Seine on the west. Cherbourg, its chief harbour, lies on the northern shore between the two promontories. The great port of Le Havre stands at the mouth of the Seine estuary, which opens into the bay of the Seine on the east. North of that point a line of high cliffs, in which occur the ports of Fécamp and Dieppe, stretches nearly to the sandy estuary of the Somme. North of that river the coast is low-lying and bordered by sand-dunes, to which succeed on the Strait of Dover the cliffs in the neighbourhood of the port of Boulogne and the marshes and sand-dunes of Flanders, with the ports of Calais and Dunkirk, the latter the principal French port on the North Sea.
To the maritime ports mentioned above must be added the river ports of Bayonne (on the Adour), Bordeaux (on the Garonne), Nantes (on the Loire), Rouen (on the Seine). On the whole, however, France is inadequately provided with natural harbours; her long tract of coast washed by the Atlantic and the Bay of Biscay has scarcely three or four good seaports, and those on the southern shore of the Channel form a striking contrast to the spacious maritime inlets on the English side.
Rivers.—The greater part of the surface of France is divided between four principal and several secondary basins.
The basin of the Rhône, with an area (in France) of about 35,000 sq. m., covers eastern France from the Mediterranean to the Vosges, from the Cévennes and the Plateau de Langres to the crests of the Jura and the Alps. Alone among French rivers, the Rhône, itself Alpine in character in its upper course, is partly fed by Alpine rivers (the Arve, the Isère and the Durance) which have their floods in spring at the melting of the snow, and are maintained by glacier-water in summer. The Rhône, the source of which is in Mont St Gothard, in Switzerland, enters France by the narrow defile of L’Écluse, and has a somewhat meandering course, first flowing south, then north-west, and then west as far as Lyons, whence it runs straight south till it reaches the Mediterranean, into which it discharges itself by two principal branches, which form the delta or island of the Camargue. The Ain, the Saône (which rises in the Faucilles and in the lower part of its course skirting the regions of Bresse and Dombes, receives the Doubs and joins the Rhône at Lyons), the Ardèche and the Gard are the affluents on the right; on the left it is joined by the Arve, the Isère, the Drôme and the Durance. The small independent river, the Var, drains that portion of the Alps which fringes the Mediterranean.
The basin of the Garonne occupies south-western France with the exception of the tracts covered by the secondary basins of the Adour, the Aude, the Hérault, the Orb and other smaller rivers, and the low-lying plain of the Landes, which is watered by numerous coast rivers, notably by the Leyre. Its area is nearly 33,000 sq. m., and extends from the Pyrenees to the uplands of Saintonge, Périgord and Limousin. The Garonne rises in the valley of Aran (Spanish Pyrenees), enters France near Bagnères-de-Luchon, has first a north-west course, then bends to the north-east, and soon resumes its first direction. Joining the Atlantic between Royan and the Pointe de Grave, opposite the tower of Cordouan. In the lower part of its course, from the Bec-d’Ambez, where it receives the Dordogne, it becomes considerably wider, and takes the name of Gironde. The principal affluents are the Ariège, the Tarn with the Aveyron and the Agout, the Lot and the Dordogne, which descends from Mont Dore-les-Bains, and joins the Garonne at Bec-d’Ambez, to form the Gironde. All these affluents are on the right, and with the exception of the Ariège, which descends from the eastern Pyrenees, rise in the mountains of Auvergne and the southern Cévennes, their sources often lying close to those of the rivers of the Loire and Rhône basins. The Neste, a Pyrenean torrent, and the Save, the Gers and the Baïse, rising on the plateau of Lannemezan, are the principal left-hand tributaries of the Garonne. North of the basin of the Garonne an area of over 3800 sq. m. is watered by the secondary system of the Charente, which descends from Chéronnac (Haute-Vienne), traverses Angoulême and falls into the Atlantic near Rochefort. Farther to the north a number of small rivers, the chief of which is the Sèvre Niortaise, drain the coast region to the south of the plateau of Gâtine.