(from Anisus, Latin name of the Ens River in the Dinarian Alps), the lowest stratum of the middle formation of the Triassic system. It was classified by the Austrian geologists W. Waagen and C. Diener in 1895. The Anisian stage is typically composed of limestone with ceratites and ammonites (Ceratites trinodosus, Sturia, Ptychites). Deposits of the Anisian stage are widely distributed in the Alps, the Himalayas, the Caucasus, the northeastern USSR, and North America.
B. M. KELLER