Everton Formation
The Everton Formation is a geologic formation in northern Arkansas that dates to the middle Ordovician Period.[2] Unconformities separate this formation from the underlying Powell Formation and the overlying St. Peter Sandstone Formation. Named for the town of Everton in Boone County, Arkansas in 1907, the Everton Formation is composed primarily of dolomite, limestone, and sandstone.
| Everton Formation Stratigraphic range: Middle Ordovician | |
|---|---|
_1.jpg.webp) Collapse breccia (Everton Formation; Arkansas) | |
| Type | Formation |
| Unit of | none |
| Sub-units | Calico Rock Sandstone Member, Jasper Limestone Member, Kings River Sandstone Member, Newton Sandstone Member, Sneeds Limestone Lentil |
| Underlies | St. Peter Sandstone |
| Overlies | Powell Formation |
| Thickness | 300 to 650 feet |
| Lithology | |
| Primary | Limestone, dolomite, sandstone |
| Other | Shale, conglomerate, chert |
| Location | |
| Region | Arkansas and Illinois |
| Country | United States |
| Type section | |
| Named for | Everton, Boone County, Arkansas[1] |
| Named by | Edward Oscar Ulrich |
Stratigraphy
Five named members of the Everton Formation are recognized (in stratigraphic order):
- Jasper Limestone Member
- Newton Sandstone Member
- Calico Rock Sandstone Member
- Kings River Sandstone Member
- Sneeds Limestone Lentil
References
- Purdue, A.H. (1907). "Cave-sandstone deposits of the southern Ozarks". Geological Society of America Bulletin. 18 (1): 251–256. doi:10.1130/gsab-18-251.
- "Everton Formation, Arkansas Geologic Survey, Ozark Plateaus, Ordovician". Archived from the original on 2014-07-14. Retrieved 2014-07-11.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 31 July 2014. Retrieved 8 July 2014.
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