Issue: 7 , Volume: 34 , Уear of publication: 2026

A more detailed re-examination of the reference section of the Campanian Stage in the Trans-Urals, on the Severnaya Sos'va River near the village of Ust'-Manya, has provided new data on the succession and allowed its biostratigraphy to be refined based on ammonites, belemnites, palynomorphs, dinocysts, radiolarians, diatoms, and silicof lagellates. Based on the dinocyst assemblage (Local zone Chlamydophorella spp.- Cepadinium subtile), it was established that the base of the section is dated Albian rather than Campanian. The sedimentology of the section was studied, and ichnofossils representing the Cruziana ichnofacies were described. It is shown that for the subdivision of the Campanian deposits, it is most convenient to use the ammonite scale of the Western Interior Seaway of North America. In the Lower Campanian, the Scaphites hippocrepis and Baculites laevis zones were identified, correlated with the Scaphites hippocrepis III and Baculites sp. (smooth) + Baculites sp. (weak f lank ribs) zones, respectively. In the Middle Campanian, a sequence of stratigraphic subspecies Baculites obtusus sosvaensis-Baculites obtusus ustmaniensis-Baculites obtusus obtusus was established, which is close to the Baculites obtusus (early form)-Baculites obtusus (late form) sequence of the Western Interior Seaway. New ammonite taxa are described. In the Campanian, Dinocysts local zone Chatangiella manumii-Isabelidinium spp. and a Lower Campanian radiolarian assemblage with Prunobrachium crassum were identified, consistent with the two-fold division of the Campanian Stage according to the European scale. The correlation of the Campanian subdivisions of the European and North American scales is discussed based on the obtained data.