The Bloyd Formation, or Bloyd Shale, is a
geologic formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...
in
Arkansas
Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...
. It preserves
fossils
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
dating back to the
Carboniferous
The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...
period.
Stratigraphy
The Bloyd Formation conformably overlies the
Hale Formation and unconformably underlies the
Atoka Formation. Five formal and one informal members are recognized in the Bloyd Formation (in stratigraphic order):
*Kessler Limestone Member
*Dye Shale Member
*Parthenon Sandstone Member (also known as the "middle Bloyd sandstone")
*Woolsey Member
*Baldwin coal (an informal unit at the top of the Woolsey Member)
*Brentwood Limestone Member
In the eastern parts of the Ozarks in Arkansas, the Bloyd Formation becomes undifferentiated with the underlying Hale Formation and is called the
Witts Springs Formation.
Paleontology
Brachiopod
Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...
s
*''
Anthracospirifer''
:''A. newberryi''
*''
Antiquatonia''
:''A. coloradoensis''
[
*'' Hustedia''
:''H. brentwoodensis''][
*'' Linoproductus''
:''L. nodosus''][
*'' Orthotetes''][
*'' Rhynchopora''
:''R. magnicosta''][
*'' Tesuquea''
:''T. formosa''][
]
Bryozoa
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic animal, aquatic invertebrate animals, nearly all living in sedentary Colony (biology), colonies. Typically about long, they have a spe ...
ns
*'' Anisotrypa''[
:''C. gracilens''][
*'']Fenestella
Fenestella (c. 52 BC – c. AD 19) was a Roman historian and encyclopaedic writer.
Biography
He flourished in the reign of Tiberius. According to Jerome, he lived from 52 BC to AD 19 (according to others 35 BC – AD 36).Pliny the Elder, ''Natur ...
''
:''F. morrowensis''[
:''F. serratula''][
:''F. venusta''][
*'' Fistulipora''][
*'' Glyptopora''
:''G. crassitoma''][
*'' Lyropora''][
*'' Matheropora''
:''M. triseriata''][
*'' Polypora''
:''P. anastomosa''][
:''P. constricta''][
:''P. elliptica''][
:''P. kesslerensis''][
:''P. magna''][
:''P. purduei''][
:''P. triseriata''][
:''P. washingtonensis''][
*'' Phyllopora''
:''P. cribosa''][
*'' Prismopora''
:''P. concava''][
*'' Rhombopora''
:''R. attenuata''][
:''R. lepidodendroides''][
:''R. snideri''][
:''R. tabulata''][
*'' Septopora''
:''S. implexa''][
:''S. reversispina''][
*'' Sulcoretepora''
:''S. brentwoodensis''][
:''S. sinuomarginata''][
*'' Tabulipora''
:''T. tuberculata''][
]
Cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s
* '' Axinolobus''
: ''A. modulus''[
* '' Bisatoceras''
: ''B. micromphalus''][
: ''B. secundum''][
* '' Boesites''
: ''B. scotti''][
* '' Branneroceras''
: ''B. branneri''][
* '' Cancelloceras''][
* '' Cymoceras''
: ''C. miseri''][
* '' Diaboloceras''
: ''D. neumeieri''][
* '' Euloxoceras''][
* '' Gastrioceras''
: ''G. adaense''][
: ''G. araium''][
: ''G. attenuatum''][
: ''G. branneri''][
: ''G. fittsi''][
* '' Glaphyrites''
: ''G. depressus''][
: ''G. morrowensis''][
: ''G. oblatus''][
* '' Homoceratoides''
: ''H. crancens''][
* '' Liroceras''][
* '' Metadimorphoceras''
: ''M. subdivisum''][
* '' Mooreoceras''
: ''M. normale''][
* '' Perigrammoceras''][
* '' Phaneroceras''
: ''P. compressum''][
: ''P. kesslerense''][
* '' Proshumardites''
: ''P. morrowanus''][
* '' Pseudoparalegoceras''
: ''P. compressum''][
: ''P. kesslerense''][
* '' Pseudopronorites''
: ''P. arkansiensis''][
: ''P. quinni''][
* '' Pseudorthoceras''
: ''P. knoxense''][
* '' Pygmaeoceras''
: ''P. pygmaeum''][
: ''P. solidum''][
* '' Solenochilus''][
* '' Stearoceras''
: ''S. smithi''][
* '' Stenopronorites''
: ''S. arkansiensis''][
* '' Syngastrioceras''
: ''S. globosum''][
: ''S. oblatum''][
* '' Verneuilites''
: ''V. pygmaeus''][
* '' Wiedeyoceras''
: ''W. smithi''][
]
Conodont
Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...
s
* '' Adetognathus''
: ''A. gigantus''[
* '' Hibbardella''][
* '' Idiognathodus''
: ''I. sinuosis''][
* '' Idiognathoides''
: ''I. convexus''][
* '' Ligonodina''
: ''L. typa''][
* '' Metalonchodina''][
* '' Neognathodus''
: ''N. kunamai''][
* '' Neoprioniodus''][
* '' Spathognathodus''
: ''S. minutus''][
* '']Streptognathodus
''Streptognathodus'' is an extinct genus of conodonts from the Late Carboniferous to Early Permian.
Use in stratigraphy Late Carboniferous
The top of the Kasimovian stage is close to the first appearance of ''Streptognathodus zethus''. The ...
''
: ''S. suberectus''[
]
Crinoid
Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are ...
s
* '' Affinocrinus''
: ''A. grandis''
Flora
Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...
*'' Archaeolithophyllum''
:''A. missouiense''[
*'' Donezella''][
*'' Eflugelia''][
*'' Girvanella''][
*'' Paraepimastopora''][
*'' Stachedoides ''
:''S. spissa''][
]
Foraminifera
Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...
*''Ammodiscus
''Ammodiscus'' is a genus in the family Ammodiscidae of textulariid foraminifera
Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology ...
''[
*'' Ammovertella''][
*'' Archaediscus''][
*'' Asteroarchaediscus''
:''A. rugosus''][
*'' Biseriella''][
*'' Calcitornella''][
:''C. adherens''][
*'' Climacammina''][
*'' Diplospahaerina''
:''D. inaequalis''][
*'']Endothyra
''Endothyra'' is an extinct genus of fusulinid belonging to the family Endothyridae. Specimens of the genus have been found in Carboniferous
The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of ...
''[
*'' Endothyranella''][
*'' Eolasiodiscus''
:''E. donbassicus''][
*'' Eosigmoilina''][
*'' Eostafella''][
*'' Hemigordius''
:''H. harltoni''][
*'' Millerella''
:''M. marblensis''][
:''M. pressa''][
*'' Monotaxinoides''
:''M. transitorius''][
*'' Neoarchaediscus''][
*'' Palaeonubecularia''][
*'' Paramillerella''
:''P. pinguis''][
*'' Planoendothyra''
:''P. evoluta''][
*'' Plectogyra''][
*'' Pseudoglomospira''][
*'' Tetrataxis''][
:''T. maxima''][
*'' Trepeilopsis''][
:''T. minima''][
*'' Tuberatina''][
:''T. plana''][
*'' Turrispiroides''
:''T. multivolutus''][
]
Ostracod
Ostracods, or ostracodes, are a Class (biology), class of the crustacean, Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant taxon, extant) have been identified,Brandão, S.N.; Antoni ...
s
*'' Amphissites''
:''A. confluens''[
:''A. rothi''][
*'' Bairdiolites''][
*'' Kegelites''][
:''K. jolliffana''][
*'' Pseudoparaparchites'']
Sponge
Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...
s
*'' Haplistion''
:''H. sphaericum''[
*'' Virgaspongia''
:''V. ichnata''][
]
Trace Fossils
A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...
*'' Conostichus''
:''C. arkansanus''
Incertae sedis
or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
*'' Asphaltina''
:''A. cordillerensis''[
*'' Clacisphaera''
:''C. laevis''][
*'' Nostocites''][
*'' Osagia''][
*'' Proninella''
:''P. strigosa''][
]
See also
* List of fossiliferous stratigraphic units in Arkansas
* Paleontology in Arkansas
References
* {{cite web, title= Fossilworks: Gateway to the Paleobiology Database, author= ((Various Contributors to the Paleobiology Database)), url= https://www.fossilworks.org, access-date= 17 December 2021
Pennsylvanian Arkansas
Carboniferous southern paleotropical deposits
Shale formations of the United States
Sandstone formations of the United States
Limestone formations of the United States