Named after
Atoka County, Oklahoma, the Atoka Formation is a
geologic formation in central and western
Arkansas, eastern
Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
, central and western
Texas, and eastern
New Mexico.
It is the surface rock of the
Boston Mountains
The Boston Mountains is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Arkansas and Oklahoma. Part of the Ozarks, the Boston Mountains are a deeply dissected plateau. The ecoregion is steeper ...
and dominates exposures in the Frontal
Ouachita Mountains of the
Arkansas River Valley.
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.
The formation is conformable with the
Bloyd Shale in the Boston Mountains and the
Johns Valley Formation
The Johns Valley Formation is a geologic formation in Arkansas and Oklahoma. It preserves fossils dating back to the Carboniferous period.
Paleofauna Bryozoans
*'' Acanthocladia''
:''A. ouachitensis''
*''Fenestella''
:''F. bendensis''
:''F. ...
in the Ouachita Mountains.
Paleofauna
Conodonts
* ''
Cavusgnathus''
: ''C. lauta''
: ''C. sinuata''
* ''
Gnathodus''
: ''G. wapanuckensis''
* ''
Gondolella
''Gondolella'' is an extinct genus of conodonts in the family Gondolellidae
Gondolellidae is an extinct family of conodonts in the order Ozarkodinida. There are three subfamilies: Mullerinae, Neogondolellinae and Novispathodinae.
Refe ...
''
: ''G. bella''
* ''
Hindeodella''
* ''
Ligonodina''
: ''L. lexingtonensis''
* ''
Ozarkodina''
: ''O. recta''
* ''
Polygnathodella
''Polygnathodella'' is an extinct genus of conodont.
Glen K. Merrill stated in 1963 that "conodont workers have considered ''Idiognathoides'' to be a junior synonym of ''Polygnathodella'' but it now proves to be a junior synonym of ''Cavusgnath ...
''
: ''P. attenuata''
: ''P. ouachitensis''
* ''
Streptognathodus''
: ''S. cancellosus''
: ''S. gracilis''
Foraminifera
* ''
Fusulinella''
: ''F. devexa''
: ''F. oliviformis''
: ''F. prolifica''
* ''
Hyperammina''
: ''H. bulbosa''
* ''
Involutina''
: ''I. semicronstrictus''
* ''
Pesudostaffella''
: ''P. atokensis''
* ''
Profusulinella''
: ''P. fittsi''
: ''P. millcreekensis''
* ''
Reophax''
: ''R. fittsi''
: ''R. tumidulus''
* ''
Thurramminoides''
: ''T. sphaeroidalis''
Trace Fossils
* ''
Conostichus
''Conostichus'' is an ichnotaxon, ichnogenus of Cnidaria, cnidarian trace fossil. They are nowadays considered to represent a burrow structure serving as a Holdfast (biology), holdfast for an anemone-like organism.
Description
''Conostichus'' i ...
''
: ''C. arkansanus''
References
Carboniferous Arkansas
Carboniferous geology of Oklahoma
Carboniferous southern paleotropical deposits
{{Carboniferous-stub