Conophyton aff. C. metula Kirichenko is abundant in dolomites of the Paraopeba Formation (Bambui Group) north of Vazante, Minas Gerais, Brazil. That suggests a middle Riphean (Proterozoic) age for the Bambui Group of this region. Such an age, in the range of 950 to 1,350 m.y., and probably closer to the younger number, is consistent with the probable ages of other now known Bambui stromatolites, as well as with the sparse and equivocal radiometric data available. It is older, however, than the Silurian age given on the 1960 geologic map of Brazil and the “upper Eocambrian” age now generally accepted.

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