Search SEDIS
| Data sets | Publications | Expeditions | Thesaurus |
Chadron Formation  | |
|---|---|
| BT | Chronostratigraphic Units |
| .Phanerozoic | |
| ..Cenozoic | |
| ...Paleogene | |
| ....Chadron Formation | |
| RT | Wyoming |
| Colorado | |
| Nebraska | |
| South Dakota | |
| White River Group | |
| upper Eocene | |
| lower Oligocene | |
| Chadronian | |
| SN | Upper Eocene to lower Oligocene. In White River Group. NE Colorado, W Nebraska, W South Dakota, and E Wyoming. Age was previously considered lower Oligocene. Indexed with upper Eocene and/or lower Oligocene as applicable. |