A gunflint-type microbiota from the Duck Creek dolomite, western Australia.

Two billion year old black chert lenses from the Duck Creek formation, northwestern Western Australia, contain abundant organically preserved microorganisms which are morphologically similar to fossils of approximately the same age from the Gunflint formation, Ontario. Entities include: a relatively small (5-15mum) coccoid taxon morphologically comparable to Huroniospora Barghoorn, a larger coccoid form comparable to an apparently planktonic alga from the Gunflint, Gunflintia Baghoorn, and Eoastrion Barghoorn (Metallogenium Perfil'ev). Gunflint-type assemblages had a wide geographic distribution in middle Precambrian times, and these assemblages may eventually prove useful as biostratigraphic indices.