| Collenia | |
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| Section ofCollenia undosa stromatolite from 2110 million year oldbanded iron formation,Biwabik | |
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| Collenia undosa stromatolite fromPrecambrian of United States | |
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| Type species | |
| †C. undosaC.Walcott | |
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Collenia isgenus offossilcyanobacteria that form a particular type ofstromatolites.[2]
Collenia are stromatolites made up of convex layers flattened in the center, forming columnar colonies. The microorganisms involved were likely photosynthetic bacteria expiring oxygen.[3]
Collenia stromatolites were very common in thePaleoproterozoic era during theSiderian andRhyacian periods, about 2.2 to 2.4 billion years ago.