Organ Rock Formation
| Organ Rock Formation | |
|---|---|
| Stratigraphic range: Early to Middle Permian: | |
Towers of red Organ Rock capped with White Rim Sandstone in Shafer Canyon in Canyonlands National Park | |
| Type | Geological formation |
| Unit of | Cutler Formation |
| Underlies | De Chelly Sandstone |
| Overlies | Cedar Mesa Sandstone |
| Lithology | |
| Primary | sandstones, siltstones, conglomerates, and mudstones. |
| Location | |
| Coordinates | 37°07′26″N 110°22′41″W / 37.124°N 110.378°W |
| Region | Colorado Plateau |
| Extent | Utah, Colorado, Arizona, New Mexico |
The Organ Rock Formation or Organ Rock Shale is a formation within the late Pennsylvanian to early Permian Cutler Group and is deposited across southeastern Utah, northwestern New Mexico, and northeastern Arizona. This formation notably outcrops around Canyonlands National Park, Natural Bridges National Monument, and Monument Valley of northeast Arizona, southern Utah. The age of the Organ Rock is constrained to the latter half of the Cisuralian epoch by age dates from overlying and underlying formations. Important early terrestrial vertebrate fossils have been recovered from this formation in northern Arizona, southern Utah, and northern New Mexico. These include the iconic Permian terrestrial fauna: Seymouria, Diadectes, Ophiacodon, and Dimetrodon. The fossil assemblage present suggests arid environmental conditions. This is corroborated with paleoclimate data indicative of global drying throughout the early Permian.