THE GEOLOGICAL TIME TABLE
1.0 = One million years
| ERAS | PERIODS | TIME SCALE (After Barrell) | CHARACTERISTIC LIFE | |
|---|---|---|---|---|
| Minimum | Maximum | |||
| PSYCHOZOIC | Recent | 1 | 1.5 | Age of Man |
| CENOZOIC | Pleistocene | |||
| Pliocene | 7 | 9 | Age of Mammals and Modern Flowering Plants | |
| Miocene | 19 | 23 | ||
| Oligocene | 35 | 39 | ||
| Eocene | 55 | 65 | ||
| MESOZOIC | Cretaceous | 95 | 115 | Age of Reptiles |
| Comanchian | 120 | 150 | ||
| Jurassic | 155 | 195 | ||
| Triassic | 190 | 240 | ||
| PALEOZOIC | Permian | 215 | 280 | Age of Amphibians and Ancient Floras |
| Pennsylvanian | 250 | 330 | ||
| Mississippian | 300 | 370 | Age of Fishes | |
| Devonian | 350 | 420 | ||
| Silurian | 390 | 460 | Age of Higher Shelled Invertebrates | |
| Ordovician | 480 | 590 | ||
| Cambrian | 550 | 700 | ||
| PROTEROZOIC | Systematic classification variable | 925 | Age of Primitive Invertebrates | |
| Long Erosional Interval | ||||
| ARCHEOZOIC | 1500 | Dawn of Unicellular Life, Algal Forms Reported | ||