Tabulate and rugose corals and stromatopores.
Narrow zone of reef talus.
Probably plate 301.
Ukhta age.
240 m thick reef, important reservoir. Algal limestones (stromatolitic) and cavernous dolomites.
Porosity up to 30 % (11 % avg.). 200-1150 mD permeability.

From ref. 1981:
Three zones of barrier reefs in area (Semiluka, Sirachoy, Ukhta. All reef periods associated with transgression.