The former quarry at Steinschab gives visitors a good insight into the rock formation of the Upper Devonian (around 380 million years ago), which was uplifted by the formation of the Rhenish Slate Mountains and tilted by folding. Fine-grained sandstones are exposed, forming 30 - 40 cm thick rock banks. This sequence of layers is also known as Nehden sandstone. Thin clay shales are sometimes intercalated between the beds. The sandstones show structures on the layer surfaces that were formed during deposition. Wave-shaped ripple marks are particularly recognizable. They are caused by the effect of flowing water on the layer boundary of a sandy sediment. Occasionally, however, fossil plant remains can also be found on the layer surfaces.
Age of the rocks: Nehden sandstone: Nehden stage, Upper Devonian (380 million years before today)