Volga Stage
Volga Stage
upper stage of the Jurassic System, named after the Volga River. It was established by S. N. Nikitin in 1881. In standard crosssections of the Volga Region this stage is made up of gray clays and marls, combustible shales, glauconitic sandstones, and sandstones with phosphorites. It is characterized by a complex of ammonites (Craspedites, Zaraiskites, Virgatites). The Volga stage is subdivided into two substages and seven zones. In the geosynclinal region of the Tethys the corresponding deposits are often referred to as the Tithonian Stage.