Fig. 1.

Small conical stromatolites often grow into fields with a regular spacing between neighboring structures. Such fields can be found in laboratory cultures (A), hot springs in YNP (B), 2.8 billion years old Archean stromatolites [reproduced from Grey (14)] (C), and 1.7 billion years old Proterozoic stromatolites from the Aphebian Mistassini Group (19) (D). Each scale bar is 1 cm. Image in (B) courtesy of the Geological Survey of Western Australia, Department of Mines and Petroleum. © State of Western Australia 2009.