Directly below Crazy Jug Point is Tapeats Amphithreater and other parts of the Tapeats Creek drainage. This photograph shows the Kaibab Formation, Toroweap Formation, and Coconino Sandstone. The Kaibab Formation was deposited by a relatively shallow ancient sea that retreated and returned a number of times (six I think) over 250 million years ago. (It is thought the cyclically retreat and return was driven by climatic, maybe glacial, changes.) For a long time Toroweap Formation was mis-identified as another layer in the Kaibab Formation but modern geologists have identified it as a separate page in Grand Canyon's textbook. For us regular folks try this to help identify these two formation: Kaibab forms a gray stepped cliff at the very rim of the Canyon and is 300 to 500 feet thick; Toroweap Formation provides the first major cliffs (steep vs stepped) in the canyon walls. Coconino Sandstone is cream colored and were formed maybe 275 million years ago by immense Sahara-like dunes of a great desert that, it is thought, stretched from south of the Grand Canyon region into Montana. The little "cave" or notch in the side of the canyon wall is (I think) in Bright Angel Shale, which is some 515 million years old. In between the Coconino Sandstone and Bright Angel Shale are five other geological layers (pages), and between Bright Angel Shale and the Colorado River, are three more pages. More information and details are available at any of the visitor centers surrounding the national park including the Kaibab National Forest's Visitor Center in Jacob Lake, Arizona.
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