Middle-Upper Ordovician trilobites and stratigraphy along the Kyrkbäcken rivulet in the Röstånga area, southern Sweden

Abstract: Middle-Upper Ordovician strata are well exposed along the Kyrkbäcken rivulet in the Röstånga area of Scania. The investigated sequence dips about 40° towards the south, and comprises about 26 m of strata. It consists largely of siliceous limestones, mudstones, shales, and bentonites. The section is generally richly fossiliferous and has yielded bivalves, brachiopods, cephalopods, gastropods, graptolites, ostracodes, and trilobites. Eighteen trilobite species have been identified. The stratigraphical subdivision is based on the succession of trilobites and on lithological characters. The lower part of the section contains a great number of bentonites and it represents the Sularp Shale. It is overlain by the Skagen Limestone. Black, bituminous limestones containing, e. g, Tretaspis ceriodes, are designated as the Mossen Fm. The middle and upper part of the section is represented by shales of the Jerrestad Fm. It has yielded a diverse trilobite fauna containing, amongst others, Amphitryon radians, Opsimasaphus jaanussoni, Liocnemis recurvus, Lonchodomas portlocki, Panderia megalophthalma, and Raphiophorus tenellus.