330 m thick in total
Gzelian to Sakmarian reef development.
Thickest of all northern Russian Asselian reefs.
Abundant Tubiphytes and bryozoans. Others are ?phylloid algae.
Palaeoaplysina limited to one bed. Radial-fibrous spherical crustification cement around Tubiphytes with bryozoans inside, peloid and block cement between spheroids. First as Gzhelian-Asselian considered.