Geologic Timescale
| Era | Period | Epoch | Approximate duration (millions of years) | Approximate number of years ago (millions of years) |
|---|---|---|---|---|
| Cenozoic | Quaternary | Holocene | 10,000 years ago to the present | |
| Pleistocene | 2 | .01 | ||
| Tertiary | Pliocene | 11 | 2 | |
| Miocene | 12 | 13 | ||
| Oligocene | 11 | 25 | ||
| Eocene | 22 | 36 | ||
| Paleocene | 71 | 58 | ||
| Mesozoic | Cretaceous | 71 | 65 | |
| Jurassic | 54 | 136 | ||
| Triassic | 35 | 190 | ||
| Paleozoic | Permian | 55 | 225 | |
| Carboniferous | 65 | 280 | ||
| Devonian | 60 | 345 | ||
| Silurian | 20 | 405 | ||
| Ordovician | 75 | 425 | ||
| Cambrian | 100 | 500 | ||
| Precambrian1 | >4,000 | 600 |
Note 1:
Not an era but the time preceding the Cambrian. The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2023, Columbia University Press. All rights reserved.
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