Petrified Trees

The southern portion of Petrified Forest National Park contains the actual petrified trees.  These tress were once a forest near the equator during the Pangaea massive super continent era.  Some unknown event lead to the forest's destruction and quick submersion by sediment.  The fallen trees absorbed some of the sediment in which they were buried and became calcified before eventually be exposed via erosion.

Here is the same petrified tree in two pictures from different angles.