CHAPTER V. CONTINENTAL SANDSTONES. France. The principal sources of sandstones fit for building in France are the Devonian, Triassic (gres bigarre), the Jurassic, containing the gres de Lux embourg, and the Tertiary series of the Paris basin, which yields the gres de Fontainebleau. In the Vosges there are the sandstones of the Permian and Trias in a position of almost relative conformity. 1 Quarries. The most important quarries are those of Villery, and those on the borders of the canal of Languedoc, by which large blocks are carried to Toulouse and other towns. The stone belongs to the class known as psammite, formed of siliceous grains in an argillaceous cement, often with flakes of mica. The town of Carcassonne is entirely built of sandstone from the quarries of Villery. 2 The sandstone of Fontainebleau, often called gres blanc, or gres commun, is chiefly found at the town of that name, at Longjumeau and Pontoise. The quarries of Busagni, near Pontoise, furnish a stone in 1 M. A. D’Orbigny, ‘Cours elt*mentaire, &c.’ ii, 392. 2 Chateau, i. 184.