975

In spite of my lingering vertigo, Nancy and I joined my sister and my niece for a quick trip to the Grand Canyon. The Grand Canyon cuts through many layers of rock, but the Coconino Sandstone is very different from the other layers. What makes it so different?

Answer:

Most of the layers of rock you see in the Grand Canyon were deposited by oceans. They contain fossils of coral, trilobites, sea shells, and other ocean life. Unlike the layers above and below it, the Coconino Sandstone is a desert deposit. It is the remains of ancient sand dunes, and still shows the grain sorting and structures that indicate sand that was blown and deposited by the wind. It also contains fossil tracks and burrows of land animals.
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