France possesses all the geo logical formations in a greater or less degree of development. The mountains generally have a nucleus of granite, which accordingly forms a prevailing rock in the Alps, on the east fron tier, and their branches south to the shores of the Mediterranean, in the Pyrenees, the Ceven nes and the elevated plateau of Langres. In the Vosges it is more sparingly developed, its place being often occupied by porphyry; and in the Jura, where limestone occurs in such enormous masses as to have given its name to a peculiar formation. The other crystalline rocks, consisting chiefly of trachytes and basalts, have received a magnificent development in Auvergne, where whole mountains are com posed of them, and where the effects of remote volcanic agency are still presented to the eye in extinct craters and lava streams. The gran ite is overlaid by primitive stratified rocks of gneiss, and of micaceous and argillaceous slates, succeeded, particularly in the Pyrenees, by mountain limestone. The secondary forma tion, commencing with this limestone and con tinued in ascending series up to the chalk, al ways possesses peculiar interest, because within it valuable mines of lead and iron, and all the workable means of coal, are included. It is largely developed in many parts of France, and furnishes a considerable number of coal and mineral fields. The Tertiary formation, includ ing all the limestones, sands and clays, above the chalk, occurs continuously in two great divisions, and partially in a number of isolated spots, and covers a vast extent of surface. The larger continuous division is in the south west, where it commences at the foot of the Pyrenees, and occupies a very large portion of the basins of the Garonne and of the Adour. The lesser but better known division takes the name of the Paris Basin, and has been made familiar to the scientific world by the labors of Cuvier and other distinguished naturalists.
Rivers and Lakes.— The great rivers of France are the Seine, Garonne, Loire, Char ente, Adour, Meuse and the Rhone. In the basin of the Garonne are its affluents, the Ariege, Tarn, Lot and Dordogne on the right bank, and the Gers on the left bank. To the north of the basin of the Garonne is that of the Loire and its tributaries, the Nievre and the Maine on the right bank, and the Allier, Loiret, Cher, Indre, Vienne and Sevre Nantaise on the left. To this basin also belong the sec ondary basins of the Vilaine and the Blavet. In the basin of the Seine are its tributaries, the Aude, Marne and Oise on the right bank, and the Yonne, Loing, Eure and Rille on the left bank. The. secondary basins are that of the Somme in the north and those of the Orne and Oise in the south. In the basin of the Meuse are its tributaries, the Sambre on its left bank, to which is added the secondary basin of the Escaut or Schelde. The basin of the Rhone occupies the whole of the territory of France which lies to the southeast of the great watershed. The tributaries of the Rhone are the Ain, the Sa6ne, the Ardeche and the Gard upon the right bank and the Isere, Drome and Durance on the left. The secondary basins
are those of the Var, Argens and Arc on the east and those of the Tet, Aude and Herault on the west. France has in all more than 212 navigable streams, with a total navigation of 5,700 miles. The lakes are few in number, and individually limited in extent. The largest, Grand-Lieu, in the department of Loire Inferieure, covers an area of only 27 square miles, and is altogether devoid of interest. The next largest, Saint Point, in the Jura, does not cover three square miles. Others of still less dimensions become more interesting from their localities in the lofty regions of the Pyrenees, or in the deep hollows of ancient craters in Auvergne.
Climate.— The climate of France greatly diversified, and cannot be described accurately without dividing it into different regions. With a very limited exception, it lies wholly within the more moderate portion of the temperate zone. France may be divided into four climatic regions according to the different vegetable products which different districts are able to mature. Within the first, and warmest, the olive is successfully cultivated. It forms the southeast part of France, and is chiefly con fined to the departments which border on the Mediterranean. The second region is character ized by the general cultivation of maize or Indian corn. The third region reaches north to the extreme limit of the profitable culture of the vine, and may be considered as deter mined by a line stretching between the mouth of the Loire and the town of Mezieres, in the department of Ardennes. All the country be yond this line is included in the fourth region. In the northwest the prevalence of winds from that direction often produces a superfluity of moisture, which manifests itself in mists or in frequent and heavy showers of rain. At the opposite extremity, the southeast, a contrary effect is produced, and a sultry, stifling wind wrinkles up the skin and not infrequently spreads fever in its most malignant form. But it is only to a few exceptional districts that these remarks apply. After allowing for them, more than four-fifths of the surface remains, under an atmosphere remarkable, more espe in its central districts, for salubrity, serenity and brightness.
Fauna and Flora.— The fauna of France does not differ materially from that of central, southern and western Europe, the only differ ence being that more cattle and sheep are found in the north of France, while the stock of horses is rather deficient. Owing to the lack of extensive forest-lands or mountain masses, the range of wild animals is growing smaller. The wolf and wild boar have not yet been extirpated; for the most part they are artificially protected for sport, especially the wolf of Brittany. In the south the silkworm is extensively reared, as also are bees producing the famous Narbonne honey. Fish is taken around the coasts in great abundance, including the tunny, sardines and herrings.