The real significance of stromatolites is that they are the earliest fossil evidence of life on Earth. The oldest known stromatolites have been dated between 3,710 million years and 3,695 million years old, and were discovered from an exposed outcrop of metacarbonate rocks in the Isua supracrustal belt (ISB) in Southwest Greenland. The ISB stromatolites predate by over 215 million years the previous most convincing and generally accepted multidisciplinary evidence for oldest life remains: stromatolites in the 3,480 million year old Dresser Formation of the Pilbara craton in Western Australia.