1. Precambrian conical stromatolite from the McArthur Group, Australia. Field photo showing weathered outcrop of small conical stromatolites (Conophyton) in the Tooganinnie Formation, McArthur Group, near Tanumbirini, 700 km southeast of Darwin, Northern Territory, Australia. 1.6 billion years old. Photo by M. R. Walter, Baas Becking Geobiological Laboratory, Canberra, Australia. Copyright by and used with the permission of the Precambrian Paleobiology Research Group - Proterozoic (UCLA).

 

2. Precambrian columnar stromatolite from the Fig Tree Group, South Africa. Cut, polished and hydroflouric acid etched vertical section of a silicified columnar stromatolite from the lower third of the Fig Tree Group, Swaziland Supergroup, at "Graywacke Hill" in the Barberton Mountainland, 30 km southeast of Barberton, eastern Transvaal, South Africa. Photo courtesy of D. R. Lowe, G. R. Byerly and M. Walsh, Louisiana State University. Archean, 3.5 billion years old. Copyright by and used with the permission of Precambrian Paleobiology Research Group - Proterozoic (UCLA).

 

3. Precambrian stromatolitic bioherm in the Belt Supergroup. Field photo showing weathered vertical section through a carbonate stromatolitic bioherm in the Proterozoic Belt Supergroup, 1.3 billion years old, on the waking trail from Logan Pass to Granite Park Chalet, Glacier National Park, northwestern Montana. Photo by J. W. Schopf, UCLA. Copyright by and used with the permission of Precambrian Paleobiology Research Group - Proterozoic (UCLA).

 

4. Precambrian cyanobacterial colony. Eoentophysalis belcerensis, an organically preserved cyanobacterial (Entophysalidacean) photographed in a petrographic thin section of stromatolitic carbonaceous chert from the Kasegalik Formation, Belcher Group (2 billion years old), from the Belcher Islands, southeastern Hudson Bay, North West Territory, Canada. Photo by H. J. Hoffman, Montreal University. Copyright by and used with the permission of Precambrian Paleobiology Research Group - Proterozoic (UCLA).

 

5. Precambrian filamentous cyanobacteria. Cyanobacteria (Nostocales) from the Bitter Springs Chert of Central Australia, 850 million years old. Optical photomicrographs showing eceptionally well preserved Oscillatoriacean, Nostocacean and, possibly, Rivulariacean trichomes in petrographic thin sections of Black chert. Photomicrograph by J. W. Schopf, UCLA. Copyright by and used with the permission of Precambrian Paleobiology Research Group - Proterozoic (UCLA).

 

6. Precambrian cyanobacteria compared with modern forms. The fossil filaments, in petrographic thin sections, are Oscillatoriaceans from the Chichkan Formation, Kazakhstan, USSR. These fossils are compared with modern Oscillatoriaceans, and the two groups show similarities in filament structure. Photomicrographs courtesy of J. W. Schopf, UCLA. Copyright by and used with the permission of the Precambrian Paleobiology Research Group- Proterozoic (UCLA).

 

7. Live cyanobacteria. A common cyanobacterium in algal mats, the Oscillatoriacean Lyngbya confervoides, was isolated from flat-laminated, microbial mat-building communities at Laguna Mormona, Baja California. Diameter of the trichome is about 20 microns. Courtesy of J. W. Schopf, UCLA. Copyright by and used with the permission of the Precambrian Paleobiology Research Group- Proterozoic (UCLA).

 

8. Live cyanobacterial colony. A four-celled colony of Gloeocapsa sp. from stromatolitic mats in Laguna Mormona, Baja California. Each cell is about 14 microns in diameter; the colony, including the sheath, is about 30 40 microns. Courtesy of J. W. Schopf, UCLA. Copyright by and used with the permission of the Precambrian Paleobiology Research Group- Proterozoic (UCLA).