Blackriverian
Tabulate corals (Labyrinthites) very dominant. 
60-95 % of rock volume.
Some stromatopores and bryozoans.
Diversity updated
Maximum thickness 15 m (rare), width below 12 m.
Tyrpanites borings.
Lourdes Limestone of the Long Point Group. Black Duck Member
Several reefs in area point-count data provided by Pruss et al. (2023)