The vastest mountain system in Europe; form the boundary between France, Germany, and Switzerland on the N. and W., and Italy on the S., their peaks mostly covered with perpetual snow, the highest being Mont Blanc, within the frontiers of France. According to height, they have been distributed into Fore, Middle, and High: the Fore rising to the limit of trees; the Middle, to the line of perpetual snow; and the High, above the snow-line. In respect of range or extent, they have been distributed into Western, Middle, and Eastern: the Western, including the Maritime, the Cottian, the Dauphiné, and the Graian, extend from the Mediterranean to Mont Blanc; the Middle, including the Pennine and Bernese, extend from Mont Blanc to the Brenner Pass; and the Eastern, including the Dolomite, the Julian, and the Dinaric, extend from the Brenner and Hungarian plain to the Danube. These giant masses occupy an area of 90,000 sq. m., and extend from the 44th to the 48th parallel of latitude.