Abstract

The Russian platform and the western slope of the Urals in the Devonian period had a similar history of development and, in general, similar directions of tectonic movements. However, there were some important differences in development of certain areas, which caused a considerable variation in the sediments and organic remains.

The study of Devonian deposits has made possible detailed local stratigraphic subdivision. These local subdivisions, in turn, have been coordinated to the maximum extent possible for the purpose of establishing stratigraphic and bio-stratigraphic divisions applicable to the platform and the Urals.

Detailed study of Devonian deposits and the principal faunal and floral groups, has made such correlations possible. Series, stages and substages are generally readily correctable throughout the region, while smaller subdivisions are generally limited to one or a few subareas.