About ten kilometers far away from Basel and 30 km from Freiburg the “Isteiner block” is a big hill near to the eastern Rhine bank. It consists of approximately 160 million years old jurassic limestone (Oxfordien). Although the Isteiner lime was formed by organisms, he contains only a few isolated fossils. Only a few jasper (flint) is to be found within the range of the quarry Kapf. Jasper (flint) develops from silicic acid, which is deposited e.g.in the flint nodules by silica bearing algae in the sediment. Close by of Istein, in Kleinkems, is a flint mine of mesolithic age, in which in Germany the digging for flint could be proven for the first time.