In the late Triassic period, from 225 to 200 million years ago, all the continents were joined together in one giant landmass called Pangea. The land occupied by these parks was approximately were Panama is now. Three rivers flowed through the area, depositing a 1,000 foot thick layer of mineral rich, hence colorful, soil. This formation is called Chinle. Later when the land rose, erosion exposed colorful layers of soil now called the Painted Desert.
Petroglyphs adorn some of the rocks. A dark "desert varnish" covers many rocks in the desert. From 2,000 to 650 years ago, Indians chipped away the desert varnish exposing the lighter rock beneath. The light colored rocks are in the patterns animals, people, and some symbols. One of the most famous collections of petroglyghs is called Newspaper Rock. Hundreds of petroglyps reach at least 20 feet up the rock face and stretch at least 40 feet horizontally. It is an impressive display.
At the bottom of the Chinle Formation are fossilized trees. In the Triassic period, the logs of 200 foot tall trees floated down the three rivers, becamed waterlogged and sank into the river bottoms. Silt covered the logs protecting them from decay. Mineral rich silicon dioxide seeped into the logs replacing plant cellulose with minerals, thus fossilizing them.
After leaving these two parks, we drove West stopping for the night at a very nice campground outside Needles, California.
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