Stromatolite (Greysonia sp.)

Vendian. Bolivia, South America. Fossils of stromatolite mounds are found across the globe. In a few spots, such as Shark Bay, West Australia, microbes are still constructing stromatolites today. Western Australia’s Strelley Pool Formation is one of the best-known locations for uncovering stromatolite fossils. Although it is hot and arid now, paleontologists and geologists believe the Strelley Pool was once the floor of a shallow ocean, where stromatolite-farming microbes would have thrived. There, seawater would have the kept the mounds moist while sunlight could still penetrate deep enough to allow photosynthesis.