Page:A book of the Cevennes (-1907-).djvu/19



HE 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