 Stromatolite

Stromatolites () or stromatoliths (from Greek "strōma" "layer, stratum" (GEN "strōmatos"), and "lithos" "rock") are layered mounds, columns, and sheet-like sedimentary rocks that were originally formed by the growth of layer upon layer of cyanobacteria, a single-celled photosynthesizing microbe.Fossilized stromatolites provide records of ancient life on Earth.