Abstract:
Based on stratigraphic distribution of ammonite genera in common for the Volgian and Tithonian stages, a new correlation scheme of the lower-middle Volgian with the Tithonian is proposed. The lower Volgian Substage corresponds to the lower Tithonian Substage coupled with the middle Tithonian semiforme Zone at least. The panderi Zone is correlative with the interval from the middle Tithonian fallauxi Zone to the upper part of the upper Tithonian microcanthum Zone. The absence of ammonite genera in common hinders the direct correlation between higher levels of the Volgian and Tithonian stages. Peculiarities in Boreal-Tethyan migrations of ammonites during the early-middle Volgian are discussed. Lingulaticeras blaschkei, a species very important for correlation of the panderi Zone with the Mediterranean zonation is described and figures of some other ammonite species, such as Sutneria asema and S. cf. eugyra, are given for the first time.
