During the Tertiary period arms of the sea spread into France—in the Paris basin from the north, in the basins of the Loire and the Garonne from the west, and in the Rhône area from the south. The changes, however, were too numerous and complex to be dealt with here.

In France, as in Great Britain, volcanic eruptions occurred during several of the Palaeozoic periods, but during the Mesozoic era the country was free from outbursts, except in the regions of the Alps and Pyrenees. In Tertiary times the Central Plateau was the theatre of great volcanic activity from the Miocene to the Pleistocene periods, and many of the volcanoes remain as nearly perfect cones to the present day. The rocks are mainly basalts and andesites, together with trachytes and phonolites, and some of the basaltic flows are of enormous extent.

On the geology of France see the classic Explication de la carte géologique de la France (Paris, vol. i. 1841, vol. ii. 1848), by Dufrénoy and Élie de Beaumont; a more modern account, with full references, is given by A. de Lapparent, Traité de géologie (Paris, 1906).

(J. A. H.)

Population.

The French nation is formed of many different elements. Iberian influence in the south-west, Ligurian on the shores of the Mediterranean, Germanic immigrations from east of the Rhine and Scandinavian immigrations in the north-west have tended to produce ethnographical diversities which ease of intercommunication and other modern conditions have failed to obliterate. The so-called Celtic type, exemplified by individuals of rather less than average height, brown-haired and brachycephalic, is the fundamental element in the nation and peoples the region between the Seine and the Garonne; in southern France a different type, dolichocephalic, short and with black hair and eyes, predominates. The tall, fair and blue-eyed individuals who are found to the north-east of the Seine and in Normandy appear to be nearer in race to the Scandinavian and Germanic invaders; a tall and darker type with long faces and aquiline noses occurs in some parts of Franche-Comté and Champagne, the Vosges and the Perche. From the Celts has been derived the gay, brilliant and adventurous temperament easily moved to extremes of enthusiasm and depression, which combined with logical and organizing faculties of a high order, the heritage from the Latin domination, and with the industry, frugality and love of the soil natural in an agricultural people go to make up the national character. The Bretons, who most nearly represent the Celts, and the Basques, who inhabit parts of the western versant of the Pyrenees, have preserved their distinctive languages and customs, and are ethnically the most interesting sections of the nation; the Flemings of French Flanders where Flemish is still spoken are also racially distinct. The immigration of Belgians into the northern departments and of Italians into those of the south-east exercise a constant modifying influence on the local populations.

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During the 19th century the population of France increased to a less extent than that of any other country (except Ireland) for which definite data exist, and during the last twenty years of that period it was little more than stationary. The following table exhibits the rate of increase as indicated by the censuses from 1876 to 1906.