Stop 1: How Wood Becomes Petrified
A log is petrified when all its original plant material is infilled or replaced by minerals.

Approximately 216 million years ago, these trees died and fell into a river. They were buried beneath layers of silt, mud, sand, and volcanic ash, which protected them from decay. Mineral-laden ground water percolated through the layers, carrying silica from the volcanic ash and other trace minerals. The absorbent dead wood became saturated with these minerals. The silica, or quartz, crystals slowly bonded with the cells of the tree replicating the organic material in perfect detail. Eventually, silica replaced the wood material.

Now this petrified forest is not made of trees, but of stone.