Lake Geneva is divided into three parts because of its different forms of formation (sedimentation, tectonic folding, glacial erosion): According to the Swiss Federal Office of Topography, swisstopo, "Lac de Genève" designates that part of the "Petit Lac", which lies within the cantonal borders of Geneva (excluding the cantonal exclave Céligny), so about from Versoix–Hermance to the Rhône outflow in Geneva. The Chablais Alps border is its southern shore, the western Bernese Alps lie over its eastern side. The high summits of Grand Combin and Mont Blanc are visible from some places. Compagnie Générale de Navigation sur le lac Léman (CGN) operates
Geology of the Alps and high peaks in the Pennine Alps and Hohe Tauern . The formation of the Mediterranean Sea is a more recent development and does not mark the northern extent of terranes originating within the African plate. The Alps form a northward convex arc around their southeastern foreland basin, the Po river basin (to be precise the south is in fact their hinterland). Quaternary and Neogene sediments in this basin lie discordant over the southernmost thrust units. In the northeast, southward dipping and internally thrusted Cenozoic foreland deposits (flysch and molasse) are found. This Bavarian and Swiss foreland basin is called