The Pitkin Formation, or Pitkin Limestone, is a fossiliferous

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 northern

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 ...

that dates to the Chesterian Series of the late Mississippian. This formation was first named the "Archimedes Limestone" by David Dale Owen in 1858, but was replaced in 1904. The Pitkin conformably overlies the Fayetteville Shale and unconformably underlies the Pennsylvanian-age Hale Formation. Some workers have considered the top of the Pitkin Formation to be a separate formation called the Imo Formation. However more recently, others have considered it as an informal member of the Pitkin Formation.

Paleofauna

Early work aimed at creating a comprehensive list for all fossils found in the Pitkin Formation was done by Easton in 1943. Unless otherwise stated, all species below can be found in his 'Fauna of the Pitkin Formation.'

Formanifera 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 for catching food and other uses; and commonly an ...

*'' Archaediscus'' :''A. stilus'' *'' Asteroarchaediscus'' :''A. rugosus'' *'' Earlandia'' *'' Endothyra'' :''E. kleina'' :''E. phrissa'' *'' Endothyranella'' *'' Eosigmoilina'' :''E. explicata'' :''E. rugosa'' *''

Eostaffella ''Eostaffella'' is an extinct genus of fusulinid belonging to the family Eostaffellidae. Specimens of the genus have been found in Carboniferous to Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million ...

'' *'' Eotuberitina'' *'' Monotaxinoides'' *'' Neoarchaediscus'' *'' Nodosarchaediscus'' *'' Paramillerella'' *'' Planospirodiscus'' *'' Plectogyra'' *'' Priscella'' *'' Pseudoammodiscus'' :''P. priscus'' *'' Pseudoglomospira'' *'' Tetrataxis'' :''T. corona'' *'' Trepeilopsis'' *'' Zellerina'' :''Z. designata'' :''Z. discoidea''

Porifera 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 th ...
, Sponges

*''

Cliona ''Cliona'' is a genus of demosponges in the family Clionaidae. It contains about eighty described species. Species Species in this genus include: * '' Cliona acephala'' Zea & López-Victoria, 2016 * '' Cliona adriatica'' Calcinai, Bavestrello, ...

Scyphozoa The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish (or "true jellies"). The class name Scyphozoa comes from the Greek word ''skyphos'' (), denoting a kind of drinking cup and alluding to the ...

*'' Conularia'' Originally considered to be a gastropod.

Anthozoa Anthozoa is a subphylum of marine invertebrates which includes the sea anemones, Scleractinia, stony corals and Alcyonacea, soft corals. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plank ...
, Corals

*'' Amplexus'' *''

Aulopora ''Aulopora'' is an extinct genus of tabulate coral Tabulata, commonly known as tabulate corals, are an order of extinct forms of coral. They are almost always colonial, forming colonies of individual hexagonal cells known as corallites defi ...

'' :''A. gracilis'' *'' Caninostrotion'' :''C. variablilis'' *'' Kinkaidia'' *'' Lesliella''Webb, Gregory., 1987., The Coral Fauna of the Pitkin Formation (Chesterian), Northeastern Oklahoma and Northwestern Arkansas. Journal of Paleontology vol. 61:3 *'' Leonardophyllum'' *'' Lonsdaleia'' :''L. major'' :''L. minor'' *'' Michellinia''Webb., Gregory., 1990., A New Tabulate Coral Species from the Pitkin Formation (Chesterian) of north-central Arkansas. Journal of Paleontology vol. 64:4. :''M. macerimuris'' *'' Parvaxon'' *''

Pleurodictyum ''Pleurodictyum'' is an extinct genus of tabulate corals, characterized by polygonal corallites. Colonies commonly encrust hard substrates such as rocks, shells and carbonate hardgrounds. Distribution Fossils of ''Pleurodictyum'' have been fou ...

'' :''P. eugenei'' :''P. meekanum'' *''

Syringopora ''Syringopora'' is an extinct genus of phaceloid tabulate coral. It has been found in rocks ranging in age from the Ordovician to the Permian, although it was most widespread during the Silurian, Devonian, and Carboniferous periods. Among other p ...

'' *''

Triplophyllum ''Triplophyllum'' is a genus of ferns in the family Tectariaceae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Taxonomy The genus ''Triplophyllum'' was erected by Richard Eric Holttum in 1986. The type spec ...

'' File:AuloporaDevonianSilicaShale.jpg, ''Aulopora'' from the

Silica Formation The Silica Formation is a geologic formation in Michigan. It preserves fossils dating back to the Devonian period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, ...

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

. File:Pleurodictyum americanum Kashong.jpg, ''Pleurodictyum americanum'' from the Givetian Kashong Shale (

Hamilton Group The Hamilton Group is a Devonian-age geological group in the Appalachian region of the United States. It is present in New York, Pennsylvania, Maryland, Ohio, West Virginia, northwestern Virginia and Ontario, Canada. It is mainly composed of mar ...

) of Livingston County,

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

. File:Syringoporid.jpg, ''Syringopora'' from the

Boone Formation The Boone Formation a discrete and definable unit of cherty limestone rock strata located in northwest Arkansas and northeast Oklahoma. The stratigraphy of the Boone Formation dates to the Mississippian age. The Boone Formation is rich in fossil ...

Blastoidea

*''

Pentremites ''Pentremites'' is an extinct genus of blastoid echinoderm belonging to the family Pentremitidae. Description These stalked echinoderms averaged a height of about but occasionally ranged up to about 3 times that size. They, like other blastoid ...

'' :''P. elongatus'' :''P. godoni'' :''P. laminatus'' :''P. obesus'' :''P. platybasis''

Crinoidea 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 ...
, Sea Lilies

*'' Agassizocrinus'' (see unidentified section) :''A. patulus'' *'' Aphelecrinus'' :''A. planus'' *'' Bronaughocrinus'' :''B. figuratus'' *'' Camptocrinus'' *'' Carinocrinus'' :''C. stevensi'' *'' Castillocrinus'' *'' Catillocrinus'' *'' Cosmetocrinus'' :''C. eventus'' *'' Cromyocrinus'' *'' Culmicrinus'' *'' Cyathocrinus'' *'' Delocrinus'' *'' Dichocrinus'' *'' Hydreionocrinus'' *'' Linocrinus'' :''L. floweri'' *''

Onychocrinus '' Onychocrinus '' is an extinct genus of crinoids. Fossil records This genus is known in the fossil records of the Carboniferous period of United States and Canada (age range: 353.8 to 318.1 million years ago). Bibliography * F. Springer. 1906 ...

'' :''O. pulaskiensis'' *'' Pachylocrinus'' *'' Paianocrinus'' :''P. aptus'' :''P. durus'' *'' Paracymbiocrinus'' :''P. pitkini'' *'' Pelecocrinus'' :''P. stereostoma'' *'' Pentaramicrinus'' :''P. modulus'' *'' Phacelocrinus'' *'' Phanocrinus'' :''P. cooksoni'' :''P. irregularis'' *'' Poteriocrinus'' *'' Pterotocrinus'' :''P. tridecibrachiatus'' *'' Scytalocrinus'' (see unidentified section) :''S. braggsi'' :''S. dunlapi'' :''S. garfieldi'' *''

Taxocrinus ''Taxocrinus'' is an extinct genus of crinoids. Fossil records This genus is known in the fossil record from the Silurian period to the Carboniferous period (age range: from 428.2 to 326.4 million years ago). These fossils have been found in ...

'' :''T. whitfieldi'' *'' Telikosocrinus'' :''T. caespes'' :''T. residuus'' *'' Zeusocrinus'' :''Z. foveatus'' Cyathocrinitidae - Cyathocrinus goniodactylus.JPG, ''Cyathocrinus goniodactylus'', on display at Galerie de paléontologie et d'anatomie comparée in

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

. Scytalocrinidae - Scytalocrinus.JPG, Fossil of ''Scytalocrinus'' from Carboniferous of the United States

Ophiuroidea Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomot ...
, Brittle Stars

This group was originally place under ''Stelleroidia'' in early studies. *'' Aganaster'' :''A. singulatus'' *'' Schoenaster''

Echinoidea Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...
, Sea Urchins

*''

Archaeocidaris ''Archaeocidaris'' is an extinct genus of echinoid that lived from the Late Devonian to the Late Permian. Its remains have been found in Africa, Europe, and North America. Sources * ''Fossils'' (Smithsonian Handbooks) by David Ward (Page 1 ...

Worms

Previous studies have grouped these diverse animals into a single, obsolete taxon: ''Vermes''. *'' Spirorbis''

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 ...
, "Moss-animals"

*'' Anisotrypa'' :''A. solida'' *''

Archimedes Archimedes of Syracuse (;; ) was a Greek mathematician, physicist, engineer, astronomer, and inventor from the ancient city of Syracuse in Sicily. Although few details of his life are known, he is regarded as one of the leading scientists ...

'' (called ''Archimedipora'' in early studies) :''A. communis'' :''A. compactoides'' :''A. compactus'' :''A. distans'' :''A. fosteri'' :''A. fragilis'' :''A. intermedia (A. intermedius)'' :''A. invaginata (A. invaginatus)'' :''A. lunatus'' :''A. magnus'' :''A. meekanus'' :''A. moorei'' :''A. pitkinensis'' :''A. proutana (A. proutanus)'' :''A. sublaxus'' :''A. swallovana (A. swallovanus)'' :''A. terebriformis'' *'' Batostomella'' *'' Chellotrypa'' :''C. distans'' *'' Chilotrypa'' :''C. regularis'' *'' Dichotrypa'' :''D. levis'' *'' Dyscritella'' *''

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. cumingsi'' :''F. matheri'' :''F. rectangularis'' :''F. serratula'' :''F. tenax'' *'' Fistulipora'' :''F. introspinosa'' *'' Glyptopora'' :''G. crassa'' :''G. michilinia'' *'' Lyropora'' :''L. solida'' *'' Meekopora'' :''M. abrupta'' :''M. tenuis'' *'' Polypora'' :''P. whitei'' *'' Rhombopora'' *'' Septopora'' :''S. biserialis'' :''S. cestriensis'' :''S. subquadrans'' *'' Tabulopora'' :''T. cestriensis'' :''T. microfistulata'' :''T. poculoformis'' :''T refiexa'' :''T. subtilis'' Fenestella_from_Couvin_Belgium

Brachiopoda

*'' Adectorhynchus'' :''A. suspectum'' *''

Athyris ''Athyris'' is a brachiopod genus with a subequally biconvex shell that is generally wider than long and a range that extends from the Silurian into the Triassic. ''Athyris'' is the type genus for the Athyrididae, which belongs to the articulate ...

'' :''A. cestriensis'' *'' Buxtonia'' :''B. arkansana '' *'' Camarophoria'' :''C. cestriensis'' :''C explanata'' *''

Chonetes ''Chonetes'' is an extinct genus of brachiopods. It ranged from the Late Ordovician to the Middle Jurassic. Species The following species of ''Chonetes'' have been described: * ''C. (Paeckelmannia)'' * ''C. baragwanathi'' * ''C. billingsi' ...

'' :''C. oklahomensis'' :''C. sericeus'' :''C. tumescens'' :'' Cliothyridina'' *''C. sublamellosa'' *''

Composita ''Composita'' is an extinct brachiopod genus that lived from the Late Devonian to the Late Permian.

'' (See unidentified section) :''C. subquadrata'' :''C. trinuclea'' *'' Crania'' :''C. infimbriata'' *'' Diaphragmus'' *'' Dielasma'' :''D. arkansanum'' :''D. formosum'' :''D. illinoisensis'' :''D. shumardanum'' :''D. whitfieldi'' *'' Echinoconchus'' (See unidentified section) :''E. alternatus'' *'' Eumetria'' :''E. costata'' :''E. pitkinensis '' :''E. vera'' *'' Girtyella'' :''G. indianensis'' *'' Hustedia'' :''H. multicostata'' *'' Krotavia'' :''K. lucerna'' *''

Lingula Lingula is Latin for "little tongue". It can stand for: * ''Lingula'' (brachiopod), a brachiopod genus of the family Lingulidae, which is among the few brachiopods surviving today but also known from fossils over 500 million years old * Lingala la ...

'' *'' Lingulidiscina'' :''L. newberryi'' var. moorefieldana and ovata *'' Linoproductus'' :''L. pileiformis'' *'' Martinia'' *'' Orthotetes'' :''O. kaskaskiensis'' :''O. stenopsis'' :''O. subglobosus'' (var. protensa) :''O. uspectum'' *''

Productus ''Productus subaculeatus'' is an extinct species of brachiopods. Its fossils are present in the Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, ...

'' :''P. cestriensis'' :''P. fasciculatus'' *''

Pustula ''Pustula'' is a genus of plant-parasitic oomycetes segregated from ''Albugo''. The name is derived from Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a di ...

'' *'' Reticularia'' :''R. setigera'' *''

Spirifer ''Spirifer'' is a genus of marine brachiopods belonging to the order Spiriferida and family Spiriferidae. Species belonging to the genus lived from the Middle Ordovician (Sandbian) through to the Middle Triassic (Carnian) with a global distribu ...

'' :''S. leidyi'' :''S. pellaensis'' *'' Spiriferina'' :''S. spinosa'' *'' Streptorhynchus'' *'' Syringothyris'' :''S. aequalis'' *'' Tetracamera'' :''T. neogenes''

Bivalvia Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of w ...
, Bivalves

This group was also referred to by another name in earlier studies: ''

Pelecypoda Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

''. *'' Allorisma'' :''A. walkeri'' *'' Astartella'' *''

Aviculopecten ''Aviculopecten'' is an extinct genus of bivalve mollusc that lived from the Early Devonian to the Late Triassic in Asia, Australia, Europe, North America, and South America.Conocardium'' :''C. peculiare'' *'' Cypricardella'' (See unidentified section) *'' Edmondia'' :''E. crassa'' (Along with ''E. crassa'' var. suborbiculoidea) :''E. pitkinensis'' *''

Leda Leda may refer to: Mythology * Leda (mythology), queen of Sparta and mother of Helen of Troy in Greek mythology Places * Leda, Western Australia, a suburb of Perth, Western Australia * Leda makeshift settlement, Bangladesh, a refugee camp ...

'' :''L. vaseyana'' *Leiopteria *Leptodesma *'' Myalina'' :''M. compressa'' :''M. longicardinalis'' *'' Nucula'' :''N. illinoisensis'' *'' Parallelodon'' *'' Pteronites'' *''

Schizodus Schizodus is an extinct genus of shallow marine clams. It lived from the Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the begin ...

'' (See unidentified section) :''S. arkansanus'' :''S. chesterensis'' :''S. depressus'' :''S. insignis'' *'' Solenomya'' *'' Sphenotus'' :''S. cherokeense'' :''S. gibsonense'' :''S. quadriplicatum''

Scaphopoda, Tusk Shells

*'' Laevidentalium''

Gastropoda The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. ...
, Snails

*''

Bellerophon Bellerophon (; Ancient Greek: Βελλεροφῶν) or Bellerophontes (), born as Hipponous, was a hero of Greek mythology. He was "the greatest hero and slayer of monsters, alongside Cadmus and Perseus, before the days of Heracles", and his ...

'' (See unidentified section) *''B. pitkinensis'' *'' Bucanella'' *'' Colpites'' *''

Euphemites ''Euphemites'' is an extinct genus of gastropod belonging to order Bellerophontida and family Euphemitidae Euphemitidae is an extinct family of Paleozoic fossil molluscs of uncertain position. They have isostrophically coiled shells and may b ...

'' :''E. incarinatus'' *'' Clabrocingulum'' *'' Gosseletina'' (See unidentified section) *''

Helcionopsis ''Helcionopsis'' is an extinct genus of paleozoic monoplacophoran in the family Tryblidiidae. The generic name is from the external resemblance which the genus bear to the recent species of the genus ''Helcion'' in family Patellidae Patellida ...

'' :''H. reticulatus'' *'' Hemizyga'' *''

Holopea ''Holopea'' is an extinct genus of fossil sea snails, Paleozoic gastropod mollusks in the family Holopeidae.MolluscaBase eds. (2022). MolluscaBase. Holopea Hall, 1847 †. Accessed through: World Register of Marine Species at: https://www.marines ...

'' :''H. newtonensis'' *'' Latischisma'' *'' Leptoptygma'' (See unidentified section) *'' Microptychis'' *'' Mourlonia'' :''M. angulata'' *'' Naticopsis'' *'' Neilsonia'' *'' Phanerotremas'' *''

Platyceras ''Platyceras'' is a genus of extinct Paleozoic sea snails, marine gastropod mollusks in the family Platyceratidae. This genus is known from the Silurian to the Middle Triassic periods and especially abundant in the Devonian and Carboniferous.Pal ...

'' :''P. subrotundum'' *'' Pseudozygopleura'' *'' Sphaerodoma'' :''S. subcorpulenta'' *'' Stegocoelia'' *'' Straparolus'' :''S. planidorsatus'' :''S. triliris'' *'' Strobeus'' (See unidentified section) *'' Strophostylus''

Cephalopoda 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, an ...

*''

Arcanoceras ''Arcanoceras'' is a genus belonging to the Eogonioloboceratidae 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 Nautil ...

'' :''A. furnishi'' *'' Coloceras'' (see unidentified section) *''

Cravenoceras ''Cravevoceras'' is an Upper Paleozoic ammonite in the goniatite family Cravenoceratidae, probably derived from '' Pachylyroceras'' and contemporary with other cravenoceratid genera like '' Caenolyroceras'', '' Tympanoceras'' and later '' Alaoce ...

'' :''C. hesperium'' :''C. richardsonianum'' *''

Cycloceras ''Cycloceras'' is an extinct nautiloid cephalopod genus from the Carboniferous of Western Europe, (Ireland and Scotland) of unknown affinity with the Orthocerida. Taxonomy ''Cycloceras'' was named by McCoy (1844 and assigned to the Michelinocer ...

'' :''C. randolphensis'' :''C. equoyahensis'' *''

Dolorthoceras ''Dolorthoceras'' is a nautiloid cephalopod from the upper Paleozoic found in Lower Devonian to Lower Permian strata in North America, Europe, Asia, and Australia. The shell is a smooth, gently expanding orthocone with straight transverse to o ...

'' (See unidentified section) :''D. eurekensis'' *'' Eoasianites'' :''E. globosus'' *'' Eumorphoceras'' :''E. bisulcatum'' *'' Metadimorphoceras'' *'' Mooreoceras'' *'' Syngastrioceras'' *'' Trizonoceras''

Trilobita Trilobites (; meaning "three lobes") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil reco ...

*'' Grifithides'' :''G. pustulosus'' *'' Kaskia'' :''K. chesterensis'' :''K. pitkinensis'' *''

Paladin The Paladins, also called the Twelve Peers, are twelve legendary knights, the foremost members of Charlemagne's court in the 8th century. They first appear in the medieval (12th century) ''chanson de geste'' cycle of the Matter of France, where ...

'' :''P. mucronatus''

Ostracoda 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, typical ...

*'' Glyptopleurain'' :''G. optina'' *'' Paraparchites'' *'' Primitia'' :''P. fayettevillensis''

Vertebrata

*'' Cladodus'' *'' Deltodus'' *''

Petalodus ''Petalodus'' is an extinct genus of cartilaginous fish from the Pennsylvanian to the Permian,Fossils (Smithsonian Handbooks) by David Ward (Page 198) known from subtriangular to rhomboidal teeth. The genus was named by Richard Owen in 1840 and t ...

Plantae, Plants

"Encrusting

Algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

" has been reported but not assigned to any genus. *''

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, ...

'' *'' Asphaltina'' :''A. cordillerensis'' *''

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 ...

'' *'' Rectangulina''

Unidentified

Following is a list of fossils also found in the Pitkin by Easton in 1943 that have gone unidentified. * A "Cup Coral" * A member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Pentremites'' * Three species within ''Agassizocrinus'' * Two species within ''Scytalocrinus'' * A totally unidentifiable Crinoid * Two species of ''Bellerophon'' * Two species of ''Gosseletina'' * Two species of ''Leptoptygma'' * Two Species of ''Strobeus'' * One species each of ''Composita'' and ''Echinoconchus'' * Two species of ''Cypricardella'' * Two species of ''Coloceras'', one of which may actually be '' Leuroceras'' * One species of ''Dolorthoceras'' * An unnamed shark

spine Spine or spinal may refer to: Science Biology * Vertebral column, also known as the backbone * Dendritic spine, a small membranous protrusion from a neuron's dendrite * Thorns, spines, and prickles, needle-like structures in plants * Spine (zoolog ...

References

{{reflist Carboniferous Arkansas Carboniferous geology of Oklahoma Carboniferous southern paleotropical deposits