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

Conodonts

• Cavusgnathus

C. lauta^[3]

C. sinuata^[4]

• Gnathodus

G. wapanuckensis^[5]

• Gondolella

G. bella^[6]

• Hindeodella^[7]
• Ligonodina

L. lexingtonensis^[8]

• Ozarkodina

O. recta^[9]

• Polygnathodella

P. attenuata^[10]

P. ouachitensis^[11]

• Streptognathodus

S. cancellosus^[12]

S. gracilis^[13]

Foraminifera

• Fusulinella

F. devexa^[14]

F. oliviformis^[15]

F. prolifica^[16]

• Hyperammina

H. bulbosa^[17]

• Involutina

I. semicronstrictus^[18]

• Pesudostaffella

P. atokensis^[19]

• Profusulinella

P. fittsi^[20]

P. millcreekensis^[21]

• Reophax

R. fittsi^[22]

R. tumidulus^[23]

• Thurramminoides

T. sphaeroidalis^[24]

Trace Fossils

• Conostichus

C. arkansanus^[25]