| Naco Formation | |
| Type: | Formation |
| Age: | Pennsylvanian |
| Period: | Pennsylvanian |
| Prilithology: | Limestone |
| Otherlithology: | Shale, siltstone |
| Region: | Arizona |
| Country: | United States |
The Naco Formation is a geologic formation in Arizona. It preserves fossils dating back to the Pennsylvanian subperiod.
Fossils from the Kohls Ranch locality of Gila County, Arizona, include bivalve and gastropod molluscs, brachiopods, bryozoans, crinoids, cnidarians and chondrichthyan teeth.[1] [2]