For many years, the stratigraphic scheme of the Permian deposits of the Urals has been based on the scheme of D.M. Rauser-Chernousova [1940]. It was developed in accordance with the distribution of individual foraminifera complexes along the section. Many of the horizons identified by D. M. Rauser-Chernousova retained their name and were adopted in the Unified Scheme of Permian sediments of the Urals in 1962, and their sections are considered stratotypic.