Baltica data makes it difficult to locate the margin in the Arctic. Ordovician faunas indicate that most of Svalbard, including Bjørnøya, was part of Laurentia, but Franz Josef Land and Kvitøya (an eastern island of the Svalbard archipelago) most likely became part of Baltica in the Timanide Orogeny. The Taymyr Peninsula, in contrast, never was part of Baltica: southern Taymyr was part of Siberia whilst northern Taymyr and the Severnaya Zemlya archipelago were part of the independent Kara Terrane in the early Palaeozoic. The eastern margin, the Uralide orogen, extends from the Arctic Novaya Zemlya archipelago to the Aral Sea. The
Franz Josef Land with streams only forming on the largest islands. The longest river is long and forms on George Land, while there are several streams on Alexandra Land, the longest being . There are about one thousand lakes in the archipelago, the majority of which are located on Alexandra Land and George Land. Most lakes are located in depressions caused by glacial erosion, in addition to a smaller number of lagoon lakes. Their sizes vary from to . Most are only deep, with the deepest measured at . The sea currents surrounding the archipelago touch eastern Svalbard and northern Novaya Zemlya. The