Hornsund is the large southernmost fjord on Spitsbergen and divides Sorkappland to the south from the Wedel Jarlsbergland to the north. The fjord's mouth faces west to the Greenland Sea, and is 12 km wide. The fjord length is 30 km, the mean depth is 90 m, and the maximal depth is 260 m. Hornsund cuts different geological formations, from the Precambrian to the west to the upper Mesozoic to the east, and it is perpendicular to the main regional fractures of Spitsbergen. The coastline of Hornsund is very diversified, with a number of embayments constituting mouth parts of valleys filled up with glaciers of mountain type protruding into the sea. Some of these embayments have appeared as late as the beginning of the last century due to recession of glaciers. The Hornsund area is situated within South Spitsbergen National Park, containing Wedel Jarlsbergland, Torellland and Sorkappland with adjacent waters. Due to the unique and pristine richness of the marine fauna and flora in Hornsund, it was nominated (along with Kongsfjorden) as one of the 12 European Biodiversity Flagship Sites by the 5th Framework Programme of the European Community.