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 South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...
. 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 in ...
dating back to the
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...
period
Period may refer to:
Common uses
* Era, a length or span of time
* Full stop (or period), a punctuation mark
Arts, entertainment, and media
* Period (music), a concept in musical composition
* Periodic sentence (or rhetorical period), a concept ...
.
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 Brachiopoda, are a phylum of trochozoan 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 end, w ...
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 invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...
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 class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s
* ''Axinolobus
''Axinolobus'' is a genus belonging to the Axinolobidae family. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloid
Nautiloids are ...
''
: ''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 (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...
s
* '' Adetognathus''
: ''A. gigantus''[
* '' Hibbardella''][
* '']Idiognathodus
''Idiognathodus'' is an extinct conodont genus in the family Idiognathodontidae.
Use in stratigraphy
The species ''Idiognathodus simulator'' made its first appearance during the Gzhelian, the youngest age of the Pennsylvanian (late Carbonife ...
''
: ''I. sinuosis''[
* '']Idiognathoides
''Idiognathoides'' is an extinct genus of conodonts.
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 ''Cavusgnat ...
''
: ''I. convexus''[
* '' Ligonodina''
: ''L. typa''][
* '' Metalonchodina''][
* '']Neognathodus
''Neognathodus'' is an extinct genus of conodonts.
Use in stratigraphy
The Bashkirian, the oldest age of the Pennsylvanian (also known as Upper Carboniferous), contains six biozones based on conodont index fossils, two of which contain ''Neo ...
''
: ''N. kunamai''[
* '' Neoprioniodus''][
* '']Spathognathodus
''Spathognathodus'' is an extinct conodont genus in the family Spathognathodontidae. It is a non-Platform conodont, from the Pennsylvanian (Carboniferous).Pennsylvanian Nonplatform Conodont Genera, I: Spathognathodus. Glen K. Merrill, Journal o ...
''
: ''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 animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...
s
* '' Affinocrinus''
: ''A. grandis''
Flora
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''.
E ...
*''Archaeolithophyllum
''Archaeolithophyllum'' is a genus of conceptacle-bearing red alga that falls in the coralline stem group. It somewhat resembles ''Lithophyllum.''
As of today, ''Archaeolithophyllum'' is the only Palaeozoic coralline to bear clear conceptacles, ...
''
:''A. missouiense''[
*'' Donezella''][
*'' Eflugelia''][
*'']Girvanella
''Girvanella'' is a fossil thought to represent the calcified sheath of a filamentous cyanobacterium known from the Burgess Shale and other Cambrian fossil deposits.
''Girvanella'' was originally described as a foraminifera. It was later assigne ...
''[
*'' Paraepimastopora''][
*'' Stachedoides ''
:''S. spissa''][
]
Foraminifera
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...
*''Ammodiscus
''Ammodiscus'' is a genus in the family Ammodiscidae of textulariid foraminifera. ''Ammodiscus'' species are vagile, epibenthic
Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, ...
''[
*'' Ammovertella''][
*'' Archaediscus''][
*'' Asteroarchaediscus''
:''A. rugosus''][
*'' Biseriella''][
*'' Calcitornella''][
:''C. adherens''][
*'' Climacammina''][
*'' Diplospahaerina''
:''D. inaequalis''][
*'' Endothyra''][
*'' 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 of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...
s
*'' Amphissites''
:''A. confluens''[
:''A. rothi''][
*'' Bairdiolites''][
*'' Kegelites''][
:''K. jolliffana''][
*'' Pseudoparaparchites'']
Sponge
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...
s
*'' Haplistion''
:''H. sphaericum''[
*'' Virgaspongia''
:''V. ichnata''][
]
Trace Fossils
A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...
*'' Conostichus''
:''C. arkansanus''
Incertae sedis
' () or ''problematica'' is a term used for a 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
This article contains a list of fossil-bearing stratigraphic units in the state of Arkansas, U.S.
Sites
See also
* Paleontology in Arkansas
References
*
{{DEFAULTSORT:Fossiliferous stratigraphic units in Arkansas
Arkansas
Stratigraphi ...
* Paleontology in Arkansas
Paleontology in Arkansas refers to paleontological research occurring within or conducted by people from the United States, U.S. state of Arkansas. The fossil Fossil record, record of Arkansas spans from the Ordovician to the Eocene. Nearly all of ...
References
* {{cite web, title= Fossilworks: Gateway to the Paleobiology Database, author= ((Various Contributors to the Paleobiology Database)), url= http://www.fossilworks.org/cgi-bin/bridge.pl?action=home, access-date= 17 December 2021
Carboniferous geology of Oklahoma
Carboniferous Arkansas
Carboniferous southern paleotropical deposits