New Data on the Distribution of Benthic Foraminifera and Microcrinoids from the Turonian–Coniacian (Upper Cretaceous) of the Volga Region

The detailed biostratigraphy of the Upper Cretaceous of the Volga region is based mainly on the study of the assemblage of benthic foraminifera. This is confirmed by the results of integrated regional studies of Turonian–Coniacian deposits. Biostratigraphic correlations are supplemented by data on radiolarians and microfossils (echinoderms, crinoids, bryozoans, calcareous sponges, and articulated brachiopods), which were identified from microfaunal samples. The identified microcrinoid assemblages increase the accuracy of both the dating of the age of deposits and their regional correlations.