Atlas Trail
The Full Sweep of Geologic Time
A walk through the whole geologic time scale, eon by period by epoch, from Earth's molten beginning to the epoch we live in now.
Stop 1 of 9.
Eras
Earth's earliest eon, from the planet's formation about 4.6 billion years ago to roughly 4 billion years ago, named for the hostile conditions of a newly accreted, still-molten world.
Stop 2 of 9.
Eras
The eon of Earth's first stable continents and the earliest confirmed life, running from about 4 to 2.5 billion years ago.
Stop 3 of 9.
Eras
The last period of the Proterozoic eon, 635 to 538.8 million years ago, when the first widespread complex multicellular organisms, the Ediacaran biota, appear in the fossil record.
Stop 4 of 9.
Eras
The Cambrian explosion establishes most major animal body plans in a geological instant, opening the Phanerozoic eon 538.8 million years ago.
Stop 5 of 9.
Eras
The Age of Fishes, when jawed fish reach striking diversity and the first forests spread across dry land, closing with one of the Big Five mass extinctions.
Stop 6 of 9.
Eras
The last period of the Paleozoic era, ending 251.9 million years ago in the most severe mass extinction Earth's record preserves.
Stop 7 of 9.
Eras
The final period of the Mesozoic era, ending 66 million years ago when an asteroid impact closed the age of the non-avian dinosaurs.
Stop 8 of 9.
Eras
The Cenozoic era's opening period, when mammals rapidly diversify into the ecological niches the dinosaurs left behind.
Stop 9 of 9.
Eras
The present epoch, beginning about 11,700 years ago at the close of the last glacial period.
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