On the Occurrence of Famennian Ammonoids in the Northern Caucasus.-

S. V. Nikolaeva and B. I. Bogoslovsky

Abstract---The Upper Famennian of the Greater Range of the Northern Caucasus contains an ammonoid assemblage of the uppermost Devonian ammonoid Kalloclymenia-Wocklumeria Genozone. The presence of characteristic species of the genera Kosmoclymenia, Cymaclymenia, Cyrtoclymenia, Synwocklumeria, Kalloclymenia, and Mimimitoceras allows the dating of the these beds to the uppermost Famennian (lower half of the Kalloclymenia-Wocklumeria Genozone and sphaeroides Zone. The occurrence of Kosmoclymenia (Muessenbiaergia) in association with Synwocklumeria is unusual because in other areas species of K. (Muessenbiaergia) became extinct prior to the appearance of Synwocklumeria. The generic composition of the assemblage studied is similar to the synchronous assemblages of Germany, Morocco, Poland, and the Orenburg Region of Russia, whereas the species composition is highly endemic. The new species Cyrtoclymenia patera, K. (Muessenbiaergia) marukhensis, K. (Muessenbiaergia) caucasica, and Cymaclymenia quieta are described.