Barsten

The Barsten is a glacial erratic boulder near Glücksburg on the Flensburg Fjord, listed as a protected cultural monument. The block is predominantly fine-grained and reddish — a type of rock known as aplite — and so thickly encrusted with lichens that the underlying igneous fabric is almost invisible to the casual eye; only closer inspection reveals the parallel jointing of its finer-grained sections. Carried south by Scandinavian glaciers during the last Ice Age, it now rests quietly in the North German lowlands, a modest but geologically revealing remnant of glacial prehistory.