FIG. 26.20 Bacterial microfossils. (a) Bacteria that probably metabolized iron in 1.9-billion-year-old rock from the Gunflint Formation in northwest Ontario, Canada. (b) Cyanobacteria preserved in 800-million-year-old silicified marine carbonates from the Draken Formation in Spitsbergen, Norway. (c) A short cyanobacterial filament from silicified tidal flat carbonates of the 1.5-billion-year-old Bilyakh Group in northern Siberia.