Forming Florissant Timeline

Drawing of Guffey Volcano — Guffey volcano as reconstructed

The valley was once surrounded by volcanoes. They formed the landscape you see today

1.08 Billion Years Ago
Pikes Peak Granite forms from a massive batholith – an intrusion of molten rock that cooled underground.

70-40 Million Years Ago
The modern Rocky Mountains form.

37 Million Years Ago
A massive flow of ash and hot gasses tears through the valley.

Fossil of a bird — Fossil of a shorebird

34.1 Million Years Ago
Volcanic ash and debris creates the conditions for fossil preservation.
1) Lake Florissant forms and preserves delicate fossils in shale.
2) The lake drains and forms a stream valley where mammals and tree stumps are preserved.
3) Lake Florissant forms again until a final volcanic pumice eruption fills the lake forever