The Oberrhätkalk is very difficult to find on the gravel banks of the Lech, because it is Weatherstone lime very similar is. It is formed by marine sediments between the Earth Ages Triassic and Jurassic emerged. At this time, the living conditions in the sea improved so that large coral reefs were formed.

These coral deposits gave rise to the Oberrhätkalk, which is very popular with climbers due to its low stratification and strength.