Lithostratigraphic units of the Helvetic Palaeogene: review, new definition, new classification

The Palaeogene lithostratigraphic units of the Swiss Helvetic Alps have been revised and in parts newly defined in order to harmonise the existing nomenclature. The resulting new classification scheme of the Helvetic Palaeogene includes (1) the basal Siderolithic Group, (2) the entire nummulite succession of Euthal Formation, Burgen Formation, Klimsenhorn Formation, Wildstrubel Formation, Niederhorn Formation, and Sanetsch Formation, (3) the Stad Formation, (4) the Muot-da-Rubi Formation, (5) the North Helvetic Flysch Group, as well as (6) South Helvetic and Ultrahelvetic (to ?North Penninic) flysch formations. The new classification further aims at simplifying the often very confusing nomenclature and the multitude of local names.