The whole of this mountain district maybe regarded as a triangular plateau rising gradually from the northwest, and tilted up at its south-eastern angle. It is composed for the most part of granite, overlapped by strata belonging to the Jurassic-system; and in many places, especially in Auvergne, the granitic rocks have been burst through by volcanoes, long since extinct, which rise like enormous protuberances from the higher parts of the platform. Towards the southern border of the district, the limestone strata overlapping the granite assume a remarkable development, exhibiting a series of flat-topped hills bounded by perpendicular cliffs some six or eight hundred feet high. "These plateaux," says Mr. Scrope, in his interesting account of the geology of Central France, "are called 'causses' in the provincial dialect, and they have a singularly dreary and desert aspect from the monotony of their form and their barren and rocky character. The valleys which separate them are rarely of considerable width. Winding, narrow, and all but impassable cliff-like glens predominate, giving to the Cevennes that peculiarly intricate character which enabled its Protestant inhabitants, in the beginning of the last century, to offer so stubborn and gallant a resistance to the atrocious persecutions of Louis XIV." Such being the character of this mountain district--rocky, elevated, and sterile--the people inhabiting it, though exceedingly industrious, are for the most very poor. Sheep-farming is the principal occupation of the people of the hill country; and in the summer season, when the lower districts are parched with drought, tens of thousands of sheep may be seen covering the roads leading to the Upper Cevennes, whither they are driven for pasture. There is a comparatively small breadth of arable land in the district. The mountains in many places contain only soil enough to grow juniper-bushes. There is very little verdure to relieve the eye--few turf-clad slopes or earth-covered ledges to repay the tillage of the farmer. Even the mountains of lower elevation are for the most part stony deserts. Chestnut-trees, it is true, grow luxuriantly in the sheltered places, and occasionally scanty crops of rye on the lower mountain-sides. Mulberry-trees also thrive in the valleys, their leaves being used for the feeding of silkworms, the rearing of which forms one of the principal industries of the district.