| Snyder Hill, a block of the Concha and Rain Valley formations in the Tucson Mountains | |
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| The Concha Limestone can be decerned from the Rain Valley by the absence of siltstone and mudstone found in the Rain Valley Formation above. Move your mouse over the picture above to see the divide more clearly. The Rain Valley Formation rests conformably on the Concha limestone, the different rocks representing different depositional environments. |
*From the Southern Arizona Guidebook III