FRANCE economic development of France has at all times been greatly influenced by the fact that it lies between the Atlantic and the Mediterranean, with easy access to both, and with good routes connecting the one with the other. The physical features of the country are comparatively simple. The Central Massif, around which the remainder of France has grown up, consists of a plateau of Archaean rock, overlain in places by Carboniferous deposits and volcanic outpourings ; it rises gently towards the south and east where the Cevennes form a steep escarpment. There are, besides, the three peripheral masses of Brittany, known as the Armorican, the Ardennes, and the Vosges, all of which consist in the main of primary rocks. The Alps in the east and the Pyrenees in the south are mountains folded during Tertiary times. Lastly, the lowland regions of Aquitaine, the basin of Paris, and the Rhone depression are areas of sedimentation filled up in part by rocks of Secondary age, and in part by debris from the surrounding uplands brought down during the Tertiary period.
The physical character of these different parts of France, and their relative position to one another and to the Atlantic and the Mediterranean, give to the country a somewhat varied climate, each region having its own peculiarities. In the Central Massif, which rises from a height of 1,500 to 2,000 feet in the north-west to over 5,500 feet in Mont Lozere in the Cevennes, the winter is long and cold with northerly winds, while the average temperature in summer does not exceed The rainfall is heavy, and in the more exposed districts the mean annual precipitation is over 60 inches. The Armorican region has, as a result of its proximity to the ocean, a temperate climate, and its summers are cool, while its winters are mild. The rainfall, which is greatest in autumn and winter, is not so _heavy as on the Central Massif, but the atmosphere generally contains a considerable amount of moisture. In the Gironde these
conditions are modified by a more southerly position, and at Bordeaux the July mean is nearly 70°F. In the sub-Pyrenean region there is a heavy rainfall and a temperature gradually decreasing with altitude.
The climate of the Mediterranean coast is very different from that of other parts of France. As a result of its southerly position and exposure, and the proximity of the sea from which the winds then blow, the winters are warm ; on the other hand the summers are hot, as the prevailing winds blow from the land during that part of the year. At Nice the range of temperature is from 46° F. in January to 75° F. in July. The summers are dry and the rain falls during the autumn and winter months. In the Rhone valley the temperature is much reduced by the cold wind, known as the mistral, caused by the dense air which lies over the Central Massif slipping down into the warm lowlands of the Rhone and the Mediterranean. The rainfall is heavier than along the coast, and amounts to between 30 and 40 inches. The Jura and the French Alps have, like the Central Massif, a greater precipitation than the Rhone valley, and, of course, a lower temperature.
Eastern France, from the Ardennes to the Vosges, lies furthest from the influence of the sea, and the range between summer and winter temperature is considerable. Owing to the presence of the mountains the rainfall is high, being between 35 and 40 inches. In the Paris basin the climate is somewhat more extreme than in Brittany. January isotherms range from 35° F. in the east to 39° F. in the west, and July isotherms from 64° F. in the north to nearly 70° F. in the south. The low rainfall, less than 30 inches over nearly the whole region, is partly due to the absence of mountains.
As each of the various upland and lowland regions of France has its distinctive physical and climatic characteristics, they form the best basis for the division of the country into natural regions.