Brief Geologic History of Monument Valley

1. The lower sandstone layer was deposited first.
2. The environment changed and rivers deposited a number of mud layers.
3. Occasional floods deposited thin layers of sand with the mud.
4. The environment changed again, and sand dunes covered the region, depositing the cliff-forming sandstone.
5. Evidence from adjacent areas indicates that other rock layers were deposited on top, and the weight of these helped turn the sand and mud into solid rock.
6. The region was uplifted and eroded by streams, with erosion removing nearly all of the sandstone and mudrock layers, except that preserved in the buttes.
7. The landscape continues to change slowly, with large blocks falling off the cliff and rock varnish developing on those surfaces that are stable for thousands of years.
8. Space aliens, if they visited, left no record.

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