| Fern Glen Formation | |
| Type: | Formation |
| Age: | Mississippian Osagean |
| Period: | Mississippian |
| Prilithology: | Limestone |
| Otherlithology: | Shale, chert[1] |
| Namedfor: | Fern Glen resort on the Meramec River |
| Namedby: | Weller in 1906[2] |
| Country: | United States |
| Underlies: | Burlington Limestone |
| Overlies: | Chouteau Group |
| Extent: | East central and southeastern Missouri, Illinois |
The Fern Glen Formation is a geologic formation in eastern and southeastern Missouri. It preserves fossils dating back to the Osagean Series of the Mississippian subperiod.
The Fern Glen is richly fossiliferous with abundant crinoids, corals, brachiopods and bryozoa.[1]