Atoka Formation

Named after Atoka County, Oklahoma, the Atoka Formation is a geologic formation in central and western Arkansas, eastern Oklahoma, central and western Texas, and eastern New Mexico.[2] It is the surface rock of the Boston Mountains and dominates exposures in the Frontal Ouachita Mountains of the Arkansas River Valley.[2]

Atoka Formation Stratigraphic range: Pennsylvanian
Type	Geologic formation
Underlies	Hartshorne Sandstone
Overlies	Bloyd Formation, Johns Valley Formation
Lithology
Primary	Sandstone
Other	Shale
Location
Region	Arkansas, Oklahoma
Country	United States
Type section
Named by	J.A. Taff[1]

Sedimentology

The Atoka Formation is a sequence of marine sandstones, siltstones, and shales, and may be as thick at 25,000 feet in the Ouachita Mountains.[2] The formation is conformable with the Bloyd Shale in the Boston Mountains and the Johns Valley Formation in the Ouachita Mountains.[2]

Paleofauna

Trace Fossils

• Conostichus

C. arkansanus[3]

References

1. Taff, J.A.; Adams, G.I. (1900). "Geology of the eastern Choctaw coal field". Twenty-First Annual Report of the United States Geological Survey, 1899-1900, Part 2, General Geology, Economic Geology, Alaska: 272, 273–274.
2. "Stratigraphic Summary of the Arkansas River Valley and Ouachita Mountains". Arkansas Geological Survey. Retrieved 2017-11-23.
3. Branson, Carl C. (May 1961). "New records of the Scyphomedusan Conostichus" (PDF). Oklahoma Geology Notes. 21 (5): 130–138. Retrieved 28 January 2018.