to summit is at Sogndal. Several rivers pour fresh water into the fjord with an annual "spring" flood in June. The mouth of the fjord is surrounded by many islands including Sula, Losna, and Hiserøyna. The Sognefjord cuts through a northwestern gneiss area with a south-west to north-east structure, and penetrates the Caledonian fold through in the inner part. There is no clear relation between the east–west direction of the main fjord and the fold patterns of the bedrock, while some of tributary fjords in the parts corresponds to fold pattern. The volume of the whole Sognefjorden including its various branches is about , while the total volume of rock eroded by glaciers from the entire Sognefjord system and adjacent valleys is about . Branches There are many smaller fjords which branch off the main fjord. Sognesjøen (mouth), Lifjorden, Høyangsfjord, Arnafjord, Esefjord, Fjærlandsfjord, Sogndalsfjord, Aurlandsfjord, Nærøyfjord (a World Heritage Site), Lærdalsfjord, Årdalsfjord, Lustrafjord (innermost), Lustrafjorden The innermost arm of the Sognefjorden is called the Lustrafjord, in the municipality of Luster. At its end is the village of Skjolden, which is an access point to Jotunheimen National Park. In earlier times, transport between Bergen and the Scandinavian inland was by boat between Bergen and Skjolden and from there on a simple road over the highlands (today Norwegian County Road 55), or by boat to Lærdal and through the mountain pass to Valdres (now European route E16). Origin and geology The valley of Sognefjord is one of various valleys of western Norway that certainly predates the Quaternary glaciations. It existed already as part of the ancient Paleic surface but had at the time much gentler slopes. The fjords of western Norway formed in connection to the east-ward tilting of much of Norway during the Cenozoic uplift of the Scandinavian Mountains. This uplift, that occurred long before the Quaternary glaciations, enabled rivers to incise deeply the Paleic relief. An estimate of 7610 km3 of rock has been eroded from the Sognefjord drainage basin since the Paleic surface formed. The fluvial and glacial erosion that made the fjords has followed structural weaknesses in the crust. During the last glaciation the ice reached a maximum thickness of nearly 3000 meters in the Sognefjord area. Confluence of tributary fjords led excavation of the deepest fjord basin. Until about 30 km from the very coast the Sognefjord glacier was apparently constricted to its narrow channel of homogeneous