The broadest division of the earths history is into eons. The most recent of these eons is the Phanerozoic, which began about 570 million years ago, and was heralded in by the explosion of marine life that brought about a new stage of planetary history. This explosion of life is known as the ‘Cambrian period’, with all other periods previous to it being known as ‘Precambrian’ (period is a much smaller division of an Eon). The Phanerazoic eon constitutes 12 per cent of the Earths collective history, and is divided into three Era’s: Palezoic, Mesozoic, and Cenozoic. It is important to keep in mind the Geological Time Scale, because the concept of deep time helps to explain the processes (ie. the ongoing process of erosion) of development the earth undertook in order to become what we see today; this understanding also helps to orient human beings as a relatively new part of the Earth, a humbling understanding when weighed against our demands on the Earth. Here we have a picture of Rose's daughters standing under a visual representation of the Paleozoic and Mesozoic Era's and the respective periods that constitue them.
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