Riphean deposits in the Biryusa Structure-Facial Zone is represented by the Karagass Group consist of the Tagul and Ipsit Formations. Stromatolites and microphitolites are common in the Prisayan region. Upper Riphean complex of Stromatolites and microphitolites is determinate in Biryusa Structure-Facial Zone. Each is compared with same of association in the stratotype section of Patom’s Zone.
