Posidonia Shale
The Posidonia Shale (German: Posidonienschiefer, also called Schistes Bitumineux in Luxembourg), is an Early Jurassic (Toarcian) geological formation in Germany, northern Switzerland, northwestern Austria, southern Luxembourg and the Netherlands. Posidonia Shale got its name from the fossils of the oyster-related bivalve "Posidonia bronni" that are commonly found throughout the formation.