Petrified Forest NP

This is the only national park bisected by Route 66. Averaging about 5,400 feet (1,600 m) in elevation, the park has a dry windy climate with temperatures that vary from summer highs of about 100 °F (38 °C) to winter lows well below freezing. More than 400 species of plants, dominated by grasses such as bunchgrass, blue grama, and sacaton, are found in the park. Fauna include larger animals such as pronghorns, coyotes, and bobcats, many smaller animals, such as deer mice, snakes, lizards, seven kinds of amphibians, and more than 200 species of birds, some of which are permanent residents and many of which are migratory. About one third of the park is designated wilderness—50,260 acres (79 sq mi; 203 km2). The Petrified Forest is known for its fossils, especially fallen trees that lived in the Late Triassic Epoch, about 225 million years ago. The sediments containing the fossil logs are part of the widespread and colorful Chinle Formation, from which the Painted Desert gets its name. Beginning about 60 million years ago, the Colorado Plateau, of which the park is part, was pushed upward by tectonic forces and exposed to increased erosion. All of the park's rock layers above the Chinle, except geologically recent ones found in parts of the park, have been removed by wind and water. In addition to petrified logs, fossils found in the park have included Late Triassic ferns, cycads, ginkgoes, and many other plants as well as fauna including giant reptiles called phytosaurs, large amphibians, and early dinosaurs. Paleontologists have been unearthing and studying the park's fossils since the early 20th century.