Bernese Alps
The Rhône valley separates them from the Chablais Alps in the west and from the Pennine Alps in the south; the upper Rhône valley separates them from the Lepontine Alps to the southeast; the Grimsel Pass and the Aare valley separates them from the Uri Alps in the east, and from the Emmental Alps in the north; their northwestern edge is not well defined, describing a line roughly from Lake Geneva to Lake Thun. The Bernese Alps are drained by the river Aare and its tributary the Saane in the north, the Rhône in the south, and the Reuss in the east.
The Bernese Alps are amongst the three highest major subranges of the Alps, together with the Pennine Alps and the Mont Blanc massif.
Geography
One of the most prominent Alpine ranges, the Bernese Alps extend from the gorge of Saint-Maurice, through which the Rhône finds its way to Lake Geneva, to the Grimsel Pass or, depending on the definition, to the river Reuss (thus including the Uri Alps). The principal ridge, a chain that runs 100 kilometres (62 mi) from west (Dent de Morcles) to east (Sidelhorn), whose highest peak is the Finsteraarhorn, forms the watershed between the cantons of Bern and Valais. Except for the westernmost part, it is also the watershed between the Rhine (North Sea) and the Rhône (Mediterranean Sea). This chain is not centered inside the range but lies close (10 to 15 km) to the Rhône on the south. This makes a large difference between the south, where the lateral short valleys descend abruptly into the deep trench forming the valley of the Rhône and the north, where the Bernese Alps extends through a great part of the canton of Bern (Bernese Oberland), throwing out branches to the west into the adjoining cantons of Vaud and Fribourg. There the mountains progressively become lower and disappear into the hilly Swiss Plateau. The Bernese Alps have a large influence on the climate of Switzerland: while their north side is very exposed to weather, their south side is protected from it. As a consequence, agriculture consists essentially of dairy farming and cattle breeding on the northern foothills, while on the sunnier southern foothills (Rhone Valley) it also consists of vineyards.
Gemmi Pass is the most central of the major passes through the main chain. It also marks the separation between two distinct sections of the Bernese Alps: the chain west of Gemmi Pass, consisting mainly of foothills with a few large glacier-covered mountains (notably Dent de Morcles, Grand Muveran, Diablerets, Wildhorn and Wildstrubel) around 3,000 metres (9,800 ft), and the chain east of Gemmi Pass, consisting mainly of summits around 4,000 metres (13,000 ft) on several subranges, with large valley glaciers between them. The latter section, contrary to the former, has very few foothills and is the most glaciated part of the Alps.
A characteristic in the orography of the Bernese Alps is, that whereas the western portion of that chain consists of a single series of summits with comparatively short projecting buttresses, the higher group presents a series of longitudinal ridges parallel to the axis of the main chain, and separated from each other by deep valleys that form the channels of great glaciers. Thus the Tschingel Glacier and the Kander Glacier, separate the portion of the main range lying between the Gemmi Pass and the Mittaghorn from the equally high parallel range of the Doldenhorn and Blümlisalp on its northern side. To the south, the same portion of the main range is divided from the still higher parallel range whose summits are the Aletschhorn and the Bietschhorn by the Lötschental and the Lötschenlücke. To this again succeeds the deep trench through which the lower part of the Aletsch Glacier flows down to the Rhône, enclosed by the minor ridge that culminates at the Eggishorn.
It is in the central and eastern portions of the range only that crystalline rocks make their appearance; the western part is composed almost exclusively of sedimentary deposits, and the secondary ridges extending through Bern and the adjoining cantons are formed of jurassic, cretaceous, or eocene strata.