The time from 3,800 million years to 2,500 million years ago; earth's crust formed; unicellular organisms are earliest forms of life.
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The period following on after Archean time is called, by geologists, Paleozoic time.
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Others divide the Precambrian into two eras, the very ancient Archean and the more recent Proterozoic.
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Rocks of Archean age cover wide areas in the interior, in West and East Africa and across the Sahara.
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A theory held by many refers the ultimate source of the iron to the igneous rocks of the Archean.
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Together, the data paint a picture of Archean evolution that is one of early development of morphological and chemical complexity.
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Appears to indicate, as I suspected, that earth has seen whole cycle or cycles of organic life before known one that begins with Archæozoic cells.