Early stromatolites Artwork of early stromatolites during a volcanic period Stromatolites boulderlike structures lower frame are an ancient form of life dating back over million years They are thought to have been among the first forms of life to emerge doing so in the Earths early history when large parts of its surface were still volcanic Stromatolites are mineralised microbial communities formed over thousands of years by layers of bluegreen algae cyanobacteria Stromatolites still exist on Earth today and are known as living fossils