Walnut

This leaf belongs to an extinct walnut species and is a rare find among the leaf fossils discovered in the Bohlinger Schlucht. Its leaves are similar in appearance to those of the common walnut, a now widely dispersed species. The walnut tree grew in the immediate vicinity of a lake, oxbow lake or floodplain. Its leaves fell into the water and were quickly covered by chalk-rich mud. As a result, the leaves were not destroyed but instead have lasted for 13.5 million years! Carbon was the only original residual chemical element in the leaf, which is why the leaf fossil is literally black as coal.