The great central plateau—The true Cévennes—The character of the range—The watershed—The Garrigues—The Boutières—Mézenc—The Coiron—The mountains of the Vivarais—The Ardèche—Volcanoes—The Camisard country—Larzac—The Hérault—The Espinouse—The Montagne Noire—Neglect of the Cévennes—Their great interest. The great central plateau of France that serves as the watershed between the Atlantic and the Mediterranean, and severs France proper—the old medieval France—from Languedoc, is due to a mighty upheaval of granite, carrying with it aloft on its back beds of schist, Jura limestone, chalk, coal, and red sandstone. The granite has not everywhere reached the surface, it has not in all parts shaken off the burden that lay on it. The superincumbent beds do not lie in position one above another, like ranges of books on shelves. Many of them over a large tract have been carried away by denudation through the action of water. The plateau under consideration stretches over an area of 3,000 square miles. It dies down towards the north-west, but reaches its highest elevation in the east and in the south. This great upland district had to be crossed before the peoples dwelling north and south of it could be fused into one. The plateau extends through the old provinces of Marche and Limousin, Auvergne, Forez, the Velay, the Vivarais, Rouergue, and the Gévaudan. But it was disturbed, broken up, and overlaid by volcanic eruptions at a comparatively recent date, pouring forth floods of lava and clouds of ash in Auvergne, le Velay, and le Vivarais. In its upheaval, moreover, the granite turned up, snapped, and exposed the superposed beds, and left them as bristling ridges to the east and south. It is this fringe that constitutes the Cévennes. These describe a half-moon, with its convexity towards the basin of the Rhône. Locally, indeed, the name Cévennes is limited to a tangle of schist ridges and deep-cleft ravines, constituting that portion of the arc which is between the Coiron and the limestone plateau of Larzac. But such is not the original limitation. The Romans undoubtedly, looking from the basin of the Rhône on the long purple chain, behind which set the sun in a glow of amber, as they passed up and down between Arles and Vienne—designated that range Cebennæ, and geographers still are disposed to so name the entire series, as constituting an orological entity, although the several portions have received distinguishing appellations. They all belong to the same system, were all in their main lines thrown up at the same time, though not by any means all of the same geological formation; and they are all peopled by the same race, all speaking the Langue d'Oc. [Illustration: THE CYCLOPSES, MOURÈZE]