While the west part of the Vosges is flat sedimentary land (well suited for mineral waters), the east is dominated by the Vosges Mountain range (including the Ballons des Vosges Regional Nature Reserve) of which the Grand Ballon at 1424m is the highest peak. The Monts Faucilles traverse the south of the department in a broad curve declining on the north into elevated plateaus, on the south encircling the upper basin of the River Saône. This chain, dividing the basins of the Rhône and the Rhine, forms part of the European watershed between the basins of the Mediterranean and Atlantic.