In the words of Svante Björck the Ancylus Lake "is perhaps the most enigmatic (and discussed) of the many Baltic stages". The lake's outlet and elevation relative to sea-level was for long time surrounded by controversy. It is now known that the lake was above sea level, included Lake Vänern, and drained westward through three outlets at Göta Älv, Uddevalla and Otteid. As result of the continued isostatic uplift of Sweden, the outlets in central Sweden were severed. In turn this resulted in the lake tipping over a till substrate at what is now the Great Belt in Denmark. Being located no less than 10 m above sea level the lake began thus to drain to the sea by the so-called Dana River between 9000 and 8900 years B.P. The forming of Dana River is thought to have caused a dramatic erosion of sediments, peatlands and forests along its way. This led initially to a relatively rapid fall in the lake level over hundreds of years to then continue at a lower pace. Another consequence of the lowering of the lake and isostatic uplift was that a north-south land bridge formed between Lake Vänern and the Ancylus Lake effectively making Lake Vänern a separate basin.