Deposits of the Zechstein Sea from the Jurassic period, and later the Weser, as well as quantities of glacial sediment and fossilized vegetation from the Cretaceous period left many natural resources in the Deister-Süntel valley. Today, Wealden sandstones of the best quality are found here along with fossilized marine animals and coal beds. Gypsum, rock salt, gravel and sand occur, as well as salt and sulphur springs and glacial erratics. The wet and swampy landscape that persisted well into the 19th century is now fertile terrain covered with loess soils.