Bilstein-Höhlen

Bilstein-Höhle: location: R 2588220, H 5650425; passage length: 10.5 m, height difference: 4 m. Bilsteiner Zwergenlabyrinth: location: R 2588190, H 5650325; passage length: 30.5 m, height difference: 3 m.

The road cutting between Oberbrombach and Bilstein shows excellently the transition from the upper Hobräck beds through the Grenzkalk to the Mühlenberg beds. The outcrop also shows the facies change of the former limestone reefs. At the bottom are fine sandstones with clayey-silty lenses and layers as well as sedimentary structures. These are unconformably overlain by an alternating sequence of biostromal reef limestones with marl and claystone layers. The limestones are partly fossil-bearing. Several normal faults dipping 55° to the north are also exposed. Above the Grenzkalk, the Mühlenberg beds are exposed along the path above the road and in two old quarries. Here there are calcareous rock layers with crinoid debris, shell and brachiopod layers, which can locally thicken into smaller limestone lenses. These then often also contain stromatoporoids and corals. On the bedding planes of the sandstones there are plant fragments, trace fossils, ripple marks and slump bodies. In the large quarry at the northern end of the profile, the succession of the upper Hobräck beds and their sedimentary structures can be studied particularly well on a high rock face. The geotope also includes 2 caves, the Bilstein Höhle and the Bilsteiner Zwergenlabyrinth.