Geosite · Aragoncillo
Fossil forest of Rillo de Gallo: a 300-million-year-old Pompeii
In Rillo de Gallo, 300-million-year-old fossilized conifer trunks are preserved as a jewel of the Molina-Alto Tajo Geopark. A volcanic eruption buried the forest beneath silica-rich, low-oxygen ash, petrifying the wood while preserving its cellular structure.
This place across time
Which eras you can read here
A single place can preserve traces from different eras. These layers connect what you see with the stories in the atlas.
- Municipality
- Aragoncillo
- Province
- Guadalajara
- Altitude
- 1,244 m
- 300 million years
- Fossil trunks
- Volcanic ash
- Geopark
A buried forest
Around 300 million years ago, a volcanic eruption blanketed a conifer forest beneath an immense fall of volcanic ash. Comparable to Pompeii, but here what was entombed and preserved was ancient timber.
How trees turn to stone
The ash was rich in silica, and fluids permeating it contained minimal oxygen, preventing wood decay. Over millenia, organic matter was replaced by minerals, molecule by molecule, turning trunks into stone that preserves original cellular structure.
Consult visit details in Rillo de Gallo.
Location
● Reference point · ● Villages · ● Places
Location diagram. Detailed map with tracks and names loads on zoom.
Reference villages: Herreria · Canales de Molina · Pardos · Rillo de Gallo.
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