A coral fauna in or below the zone of Nemagraptus pertenuis at Cliefden Caves is the oldest so far discovered in Australia. The genera represented are T'etradium, Billingsaria, Nyctopora, Coccoseris and Propora. For these last two genera the Cliefden Caves Limestone is the earliest known appearance.Another fauna, from the Bowan Park and Regan's Creek Limestones, contains ? Lichenaria, ?Coccoseris, Palcwoporites, Propora, Heliolites and Eofletcheria, with dasycladacean alge. This may be either late Middle or Upper Ordovician, or because of the presence of Palwoporites, possibly Lower Silurian.Calapoecia (first Australian record) occurs in Portion 41, Parish Boree Cabonne, near Cudal. The species is very similar to a Black River-Trenton-Richmond one from Canada.Plasmoporella, Plasmopora and Propora occur in the Cargo Creek Limestone, which may be Upper Ordovician or Lower Silurian, and the Canomodine limestone, though recrystallised, appears to have a similar fauna.