300 reefs.
Maximum 12 m thick, 200 m wide.
Massive biolithite with scattered pockets of calcarernite.
Cerioid and phaceloid rugosans, stromatopores, tabulate corals.
Tabulate corals (Favosites>Halysites, Syringopora) predominate. Stromatoporoids second. Thick micrite encrustations.

High porosity and occasional bitumen showings.