Akchagyl Strata

(named for the Akchagyl natural landmark on the Krasnovodsk Peninsula), a Pliocene subdivision in the Caspian basin. These strata were distinguished by the Russian geologist N. I. Andrusov in 1896. They consist of marine limestones, marls, clays, and sands, with a characteristic complex of Pelecypoda (Avimactra subcaspia, A. karabugasica, and others). Many investigators regard these strata as a stage of the Neocene system.