Ediacaran
adj.— «Geologists have added a new period to their official calendar of Earth’s history—the first in 120 years. The Ediacaran Period covers some 50 million years of ancient time on our planet from 600 million years ago to about 542 million years ago. It officially becomes part of the Neoproterozoic, when multi-celled life forms started to take hold on Earth.» —“Geological time gets a new period” BBC (U.K.) May 17, 2004. (source: Double-Tongued Dictionary)
Further reading
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