The microorganisms that evolved during the Archean era had extraordinary impacts on this planet. If not for them, Earth would not have developed the oxygen-rich atmosphere needed to support the evolution of multicellular organisms. However, our direct observations of life from that time come from only fifteen known fossiliferous Archean rock formations, and the exploration of these formations is not complete. As a result, study of these formations can yield new insights into the communities of microfossils that lived in the Archean era and previously unobserved microfossil morphologies. Here we present spheroid microfossils, as well as unusually large microfossils with clublike morphologies not previously observed in Archean microorganisms. These microfossils were three-dimensionally preserved in black chert from the Gamohaan Formation, Griqualand West Basin, Kaapvaal Craton, South Africa. These microfossils were discovered in a small, domal stromatolite that formed in a shallow marine setting on a carbonate shelf system at 2.52 billion years ago (Sumner and Bowring, 1996), just one to two hundred million years before the Great Oxidation Event.