Pitkin Formation
| Pitkin Formation | |
|---|---|
| Stratigraphic range: Upper Visean-Serpukhovian[1] | |
| Type | Formation | 
| Sub-units | Imo Shale | 
| Underlies | Hale Formation | 
| Overlies | Fayetteville Formation | 
| Thickness | up to and over 400 feet[2] | 
| Lithology | |
| Primary | Limestone[1] | 
| Other | Shale | 
| Location | |
| Region | Arkansas | 
| Country | United States | 
| Type section | |
| Named for | Pitkin post office, Washington County, Arkansas[3] | 
| Named by | George Irving Adams and Edward Oscar Ulrich | 
The Pitkin Formation, or Pitkin Limestone, is a fossiliferous geologic formation in northern Arkansas that dates to the Chesterian Series of the late Mississippian.[4] This formation was first named the "Archimedes Limestone" by David Dale Owen in 1858, but was replaced in 1904.[3] The Pitkin conformably overlies the Fayetteville Shale and unconformably underlies the Pennsylvanian-age Hale Formation. Some workers have considered the shales at the top of the Pitkin Formation to be a separate formation called the Imo Formation. More recently, others have considered the Imo to be 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.[1] Unless otherwise stated, all species below can be found in his 'Fauna of the Pitkin Formation.'
- Archaediscus
 
- A. stilus[5]
 
- Asteroarchaediscus
 
- A. rugosus[5]
 
- Endothyranella[6]
 - Eosigmoilina
 
- Eostaffella[5]
 - Eotuberitina[5]
 - Monotaxinoides[5]
 - Neoarchaediscus[5]
 - Nodosarchaediscus[5]
 - Paramillerella[6]
 - Planospirodiscus[5]
 - Plectogyra[6]
 - Priscella[5]
 - Pseudoammodiscus
 
- P. priscus[5]
 
- Pseudoglomospira[5]
 - Tetrataxis[5]
 
- T. corona[6]
 
- Trepeilopsis[5]
 - Zellerina
 
Porifera, Sponges
- Conularia Originally considered to be a gastropod.
 
Anthozoa, Corals
- Amplexus
 - Aulopora
 
- A. gracilis
 
- Caninostrotion
 
- C. variablilis
 
- L. major
 - L. minor
 
- Michellinia[8]
 
- M. macerimuris[8]
 
- Parvaxon[7]
 - Pleurodictyum
 
- P. eugenei
 - P. meekanum
 
- 
			
Aulopora from the Silica Formation of Ohio. - 
			
Pleurodictyum americanum from the Givetian Kashong Shale (Hamilton Group) of Livingston County, New York. - 
			
Syringopora from the Boone Formation of Arkansas. 

Crinoidea, Sea Lilies
- Agassizocrinus (see unidentified section)
 
- A. patulus [10]
 
- Aphelecrinus
 
- A. planus[10]
 
- Bronaughocrinus
 
- B. figuratus[10]
 
- Camptocrinus[10]
 - Carinocrinus
 
- C. stevensi[10]
 
- Castillocrinus
 - Catillocrinus[10]
 - Cosmetocrinus
 
- C. eventus[10]
 
- Cromyocrinus
 - Culmicrinus[10]
 - Cyathocrinus
 - Delocrinus
 - Dichocrinus[10]
 - Hydreionocrinus
 - Linocrinus
 
- L. floweri[10]
 
- O. pulaskiensis[10]
 
- Pachylocrinus
 - Paianocrinus
 
- Paracymbiocrinus
 
- P. pitkini[10]
 
- Pelecocrinus
 
- P. stereostoma[10]
 
- Pentaramicrinus
 
- P. modulus[10]
 
- Phacelocrinus[10]
 - Phanocrinus
 
- Poteriocrinus
 - Pterotocrinus
 
- P. tridecibrachiatus[10]
 
- Scytalocrinus (see unidentified section)
 
- T. whitfieldi[10]
 
- Telikosocrinus
 
- T. caespes
 - T. residuus
 
- Zeusocrinus
 
- Z. foveatus
 
- 
			Cyathocrinus goniodactylus, on display at Galerie de paléontologie et d'anatomie comparée in Paris.
 - 
			Fossil of Scytalocrinus from Carboniferous of the United States
 
Ophiuroidea, Brittle Stars
This group was originally place under Stelleroidia in early studies.[1]
- Aganaster
 
- A. singulatus
 
- Schoenaster
 
Echinoidea, Sea Urchins

Worms
Previous studies have grouped these diverse animals into a single, obsolete taxon: Vermes.[1]
Bryozoa, "Moss-animals"
| Stereo image | |||
|---|---|---|---|
  | |||
  | |||
  | |||
  | |||
| Fossilized skeleton of Archimedes Bryozoan. | |||
- Anisotrypa
 
- A. solida [1]
 
- Archimedes (called Archimedipora in early studies)[1]
 
- A. communis [1][11]
 - A. compactoides [11]
 - A. compactus [11]
 - A. distans [1][11]
 - A. fosteri [11]
 - A. fragilis [11]
 - A. intermedia (A. intermedius) [1][11]
 - A. invaginata (A. invaginatus) [1][11]
 - A. lunatus [11]
 - A. magnus [11]
 - A. meekanus [11]
 - A. moorei [11]
 - A. pitkinensis [11]
 - A. proutana (A. proutanus) [1][11]
 - A. sublaxus [11]
 - A. swallovana (A. swallovanus) [1][11]
 - A. terebriformis [11]
 
- Batostomella [1]
 - Chellotrypa
 
- C. distans [11]
 
- Chilotrypa
 
- C. regularis [1]
 
- Dichotrypa
 
- Fistulipora
 
- Glyptopora
 
- Lyropora
 
- Meekopora
 
- Polypora
 
- P. whitei [1]
 
- Tabulopora
 

- Adectorhynchus
 
- A. suspectum [12]
 
- A. cestriensis
 
- Buxtonia
 
- B. arkansana
 
- Camarophoria
 
- C. cestriensis
 - C explanata
 
- C. oklahomensis
 - C. sericeus
 - C. tumescens
 - Cliothyridina
 
- C. sublamellosa
 - Composita (See unidentified section)
 
- C. subquadrata
 - C. trinuclea
 
- 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
 - Lingulidiscina
 
- L. newberryi var. moorefieldana and ovata
 
- L. pileiformis
 
- Martinia
 - Orthotetes
 
- O. kaskaskiensis
 - O. stenopsis[12]
 - O. subglobosus (var. protensa)
 - O. uspectum
 
- P. cestriensis
 - P. fasciculatus
 
- Pustula
 - Reticularia
 
- R. setigera
 
- S. leidyi
 - S. pellaensis
 
- S. spinosa
 
- Streptorhynchus
 - Syringothyris
 
- S. aequalis
 
- Tetracamera
 
- T. neogenes
 
Bivalvia, Bivalves
This group was also referred to by another name in earlier studies: Pelecypoda.[1]
- Allorisma
 
- A. walkeri
 
- Astartella
 - Aviculopecten
 
- A. batesvillensis
 - A. eurekensis
 - A. keoughensis
 - A. morrowensis
 - A. multilineatus
 - A. pitkinensis
 
- C. peculiare
 
- Cypricardella (See unidentified section)
 - Edmondia
 
- E. crassa (Along with E. crassa var. suborbiculoidea)
 - E. pitkinensis
 
- Leda
 
- L. vaseyana
 
- Leiopteria
 - Leptodesma
 - Myalina
 
- M. compressa
 - M. longicardinalis
 
- N. illinoisensis
 
- Parallelodon
 - Pteronites
 - Schizodus (See unidentified section)
 
- S. arkansanus
 - S. chesterensis
 - S. depressus
 - S. insignis
 
- Solenomya
 - Sphenotus
 
- S. cherokeense
 - S. gibsonense
 - S. quadriplicatum
 
Scaphopoda, Tusk Shells
Gastropoda, Snails
- Bellerophon (See unidentified section)
 - B. pitkinensis
 - Bucanella
 - Colpites
 - Euphemites
 
- E. incarinatus
 
- Clabrocingulum
 - Gosseletina (See unidentified section)
 - Helcionopsis
 
- H. reticulatus
 
- Hemizyga
 - Holopea
 
- H. newtonensis
 
- Latischisma
 - Leptoptygma (See unidentified section)
 - Microptychis
 - Mourlonia
 
- M. angulata
 
- Naticopsis
 - Neilsonia
 - Phanerotremas
 - Platyceras
 
- P. subrotundum
 
- Pseudozygopleura
 - Sphaerodoma
 
- S. subcorpulenta
 
- Stegocoelia
 - Straparolus
 
- S. planidorsatus
 - S. triliris
 
- Strobeus (See unidentified section)
 - Strophostylus
 
- A. furnishi[13]
 
- Coloceras (see unidentified section)
 - Cravenoceras
 
- C. hesperium
 - C. richardsonianum[13]
 
- C. randolphensis
 - C. equoyahensis
 
- Dolorthoceras (See unidentified section)
 
- D. eurekensis
 
- Eoasianites
 
- E. globosus
 
- Eumorphoceras
 
- E. bisulcatum[13]
 
- Grifithides
 
- G. pustulosus
 
- Kaskia
 
- K. chesterensis
 - K. pitkinensis[14]
 
- P. mucronatus
 
- Glyptopleurain
 
- G. optina
 
- Paraparchites
 - Primitia
 
- P. fayettevillensis
 
Plantae, Plants
"Encrusting Algae" has been reported but not assigned to any genus.[1]
- Archaeolithophyllum[6]
 - Asphaltina
 
- A. cordillerensis[5]
 
- Girvanella[5]
 - Rectangulina[5]
 
Unidentified
Following is a list of fossils also found in the Pitkin by Easton in 1943 that have gone unidentified.[1]
- A "Cup Coral"
 - A member of the genus 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
 
See also
References
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am Easton, William H., The Fauna of the Pitkin Formation of Arkansas., Journal of Paleontology: vol. 17:2. March, 1943.
 - ^ McFarland, John David (2004) [1998]. "Stratigraphic summary of Arkansas" (PDF). Arkansas Geological Commission Information Circular. 36: 12–13. Archived from the original (PDF) on 2016-12-21. Retrieved 2018-05-31.
 - ^ a b Adams, G.; Ulrich, E. (1904). "Zinc and lead deposits of northern Arkansas". U.S. Geological Survey Professional Paper. 24: 27, 109.
 - ^ Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to thefix Paleobiology Database". Retrieved 17 December 2021.
 - ^ a b c d e f g h i j k l m n o p q r s t u v Brenckle, Paul (1977). "Foraminifers and other calcareous microfossils from Late Chesterian (Mississippian) strata of northern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 73–87. Retrieved 3 February 2018.
 - ^ a b c d e f Nodine-Zeller, Doris E. (1977). "Microfauna from Chesterian (Mississippian) and Morrowan (Pennsylvanian) rocks in Washington County, Arkansas, and Adair and Muskogee Counties, Oklahoma" (PDF). Oklahoma Geological Survey Guidebook. 18: 89–99. Retrieved 3 February 2018.
 - ^ a b c d Webb, Gregory., 1987., The Coral Fauna of the Pitkin Formation (Chesterian), Northeastern Oklahoma and Northwestern Arkansas. Journal of Paleontology vol. 61:3
 - ^ a b Webb., Gregory., 1990., A New Tabulate Coral Species from the Pitkin Formation (Chesterian) of north-central Arkansas. Journal of Paleontology vol. 64:4.
 - ^ a b c d Horowitz, Alan S.; Macurda Jr, D. B. (1977). "Late Mississippian and Early Pennsylvanian blastoids from northeastern Oklahoma and northwestern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 169–170. Retrieved 31 January 2018.
 - ^ a b c d e f g h i j k l m n o p q r s t u v w x Strimple, Harrell L. (1977). "Chesterian (Upper Mississippian) and Morrowan (Lower Pennsylvanian) crinoids of northeastern Oklahoma and northwestern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 171–176. Retrieved 30 January 2018.
 - ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai Horowitz, Alan S. (1977). "Late Mississippian and Early Pennsylvanian bryozoan faunas of Arkansas and Oklahoma: a review" (PDF). Oklahoma Geological Survey Guidebook. 18: 101–105. Retrieved 3 February 2018.
 - ^ a b Henry, Thomas W.; Gordon Jr., Mackenzie (January 1985). "Chesterian davidsoniacean and orthotetacean brachiopods, Ozark region of Arkansas and Oklahoma". Journal of Paleontology. 59 (1): 32–59. JSTOR 1304826.
 - ^ a b c d e f Saunders, W. Bruce; Manger, Walter L.; Gordon Jr., Mackenzie (1977). "Upper Mississippian and Lower and Middle Pennsylvanian ammonoid biostratigraphy of northern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 117–137. Retrieved 1 February 2018.
 - ^ Brezinski, David K. (31 March 2017). "Some New Late Mississippian Trilobites from Oklahoma and Arkansas". Annals of Carnegie Museum. 84 (2): 173–178. doi:10.2992/007.084.0203.
 
