Colonial cyanobacteria of the genus ostiana (microcystis) from the upper vendian of Arkhangelsk region

The study of organic films from Zimnie Gory Beds, Ust'-Pinega Formation (Upper Vendian) permits to identify numerous colonial coccoid cyanobacteria ofgenus Ostiana Hermann (0. microcystis and 0. aphanotece sp. nov.). Spheroid acritarchs of genus Leiospheridia Eis. (L. tenuissima and L. ternata) are occasionally found together with the colonial microfossils. Pyritized organic films with filamentous Leiotrichoides tipicus were found in some layers ofUst'-Pinega formation.