Two hundred million years ago, the supercontinent of Pangaea contained the earth's entire landmass. An early variety of pine trees grew along waterways in the region of Pangaea that is now Arizona, where flooding, wind, and death felled whole forests of these 200-foot-tall trees.

'Chinle' means "flowing through." The Navajo Tribe uses this word to describe soils washed down from Arizona's fertile highlands into its otherwise arid canyons and valleys. It also describes the sediment and organic materials that flowed into Pangaea's floodplains, including the remains of animals, trees, and other plants. Overtime, the accumulation of these deposits compressed into sedimentary rock that makes up the Chinle Formation of eastern Arizona's Petrified Forest National Park.