The overthrust was formed during the formation of the Kellerwald in the so-called "Variscan mountain building" about 300 million years ago, when the earth's crust was constricted, folded and shifted against each other.
In the sequence of strata, clay and siliceous shales from the Lower Carboniferous alternate from east to west with Upper Devonian red and banded shales and again Carboniferous clay and siliceous shales (exposed in the quarry). Intercalated are volcanically formed diabases. The clay shales contain fossils such as goniatites and traces of the mussel Posidonia becheri.
Tip
If you want to visit the outcrop, it is best to start at the water treading pool below the quarry. There is sufficient parking space for cars here. On site, information boards inform about the formation and geology of the Koppe.