On Stratigraphy and Flora of Cretaceous Deposits in the Chulym-Yenisei Region, Western Siberia

The stratigraphic positions and substantiation of ages of the Serta, Chulym, Antibes, and Sym paleofloras are considered. It is shown that these paleofloras most likely did not replace each other during the evolution, but rather existed simultaneously on the geological time scale. The Kiya, Simonovo, and Sym formations do not have distinct stratigraphic boundaries, expressed mapping features, or reliable paleontological evidence for age substantiation. They should be considered as a united stratigraphic unit.