A Lower Silurian (Llandoverian) halysitid fauna from the Berge Limestone Formation, Norderön, Jämtland, central Sweden

Halysitid corals from the Llandoverian (Early Silurian) Berge Limestone Formation in Jämtland, central Sweden, are described. The investigation of the halysitid corals was done on material derived from the Norderön Island in Lake Storsjön, central Sweden. The Berge Limestone is rich in fossils, especially tabulate corals, and species described and discussed are Catenipora distans (Eichwald), Catenipora cf. maxima (Fischer-Benzon), Catenipora sp.1, Catenipora sp.2, Halysites cf. junior (Klaamann). The fauna and lithology indicate a muddy/silty environment between fairweather wave base and storm wave base, within the photic zone. The bottom was fine-grained and firm enough for e.g. corals to attach directly to the substratum. The Berge Limestone Fm is correlated with the Rytteråker Fm in the Oslo region (Norway). Problems with taxonomic procedures concerning halysitids are briefly discussed.