Fossil-bearing slates are exposed in the Kranbuche outcrop near Züschen. They are among the oldest rocks in the so-called Züschen Saddle and can be dated to the Lower Devonian period (around 390 million years ago). The fossils are brachiopods (arthropods), mussels and trilobites (three-lobed crustaceans). Snails are less common. Corals and numerous stalk limbs of crinoids are also found. As their genus has a relatively limited lifespan within the Earth's history, it was possible to prove the relative age of the find layer as younger Lower Devonian with the help of these key fossils.
The rocks and fossils from the Kranbuche outcrop are presented in an exhibition in the Borgs Scheune local history museum.
Age of the rocks: Spherosiderite slate: Emsian stage, Lower Devonian (approx. 390 million years before present)