Maia Stage

(named after the Maia River, a tributary of the Aldan), uppermost stage of the Middle Cambrian. The name was proposed by the Soviet geologist F. G. Gurari in 1955. The paleontological substantiation for the stage was given by N. V. Pokrovskaia and N. E. Chernysheva. The type section of the Maia stage is represented by limestones and marls. The stage is characterized by a succession of trilobite species of the families Paradoxididae, Dorypygidae, Agnostidae, and Corynexochidae and the appearance of representatives of the families Anomacaridae, Liostrocidae, Arcrocephalitidae, and others. Deposits of the Maia stage are found on the Siberian Platform, in Kazakhstan, and in the Altai-Saian region.