Evolutionists, by uniformitarian reasoning, have devised a column that supposedly represents millions of years of history. The Geologic Column is an attempt to correlate the “evolution” of life with the geology of the earth. It has 3 major eras, the Paleozoic (ancient life), the Mesozoic (middle life) and Cenozoic (recent life). There are a dozen or so periods, (e.g. the Cretaceous, Permian, or Cambrian periods), each of which have distinctive forms of life. In theory, this spans the last 600 million years of the earth’s history. The periods each have a set of fossils that are typically found in that period, and are thus called Index Fossils.
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