Threeforks Shale, Jefferson Island Co., Montana (measured section 3 of author) (Devonian of the United States)

Where: Jefferson Island County, Montana (45.9° N, 112.0° W: paleocoordinates 14.8° S, 46.6° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Platyclymenia zone, Three Forks Shale Formation, Middle Famennian (370.6 - 364.7 Ma)

• species of ammonoid found by the author correspond to the Oberdevon III, the lower Platyclymenia horizon in the European stratigraphic column [JA: originally entered as late Devonian, but the lower Platyclymenia horizon corresponds to the Pa. trachytera conodont zone and is middle Famennian]

• formation-level stratigraphic resolution

Environment/lithology: marine; gray, yellow shale and limestone

• author gives no detailed description of lithology where she collected; however, through historic descriptions included in the text, the formation is divided into two shale units divided by limestone. this collection came from the lower shale, which is described as variegated in color (reds, yellow, brown) and finely laminated and the middle limestone, which is grey and nodular.

Collection methods: surface (in situ),

Primary reference: P. J. Renzetti. 1961. Fauna of the Threeforks Shale (Devonian) of Southwestern Montana. 1-342 [A. Miller/K. Layou/M. Uhen]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 6975: authorized by Arnold Miller, entered by Karen Layou on 18.04.2000

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
unclassified
  -
Hunanospirifer monticola, Hunanospirifer ? gallatinensis, Hunanospirifer animasensis, Nickelsopora sp. n. sp.
Nickelsopora sp. n. sp.
Nickelsopora n. sp. A
Strophomenata
 Orthotetida - Areostrophiidae
"Schuchertella cf. arctostriata" = Floweria arctostriata
"Schuchertella cf. arctostriata" = Floweria arctostriata Hall 1843
 Orthotetida - Schuchertellidae
Schuchertella cf. extensus, Schuchertella sp.
Schuchertella sp. Girty 1904
 Productida - Productidae
Leioproductus coloradensis, Leioproductus montanensis n. sp., Leioproductus plicatus
 Productida - Sentosiidae
"Echinoconchus ? laminatus" = Laminatia laminata
"Echinoconchus ? laminatus" = Laminatia laminata Kindle 1909
Rhynchonellata
 Spiriferida - Mucrospiriferidae
Eleutherokomma raymondi
 Spiriferida - Cyrtospiriferidae
? Cyrtospirifer perryi n. sp., ? Cyrtospirifer bertrandi n. sp., Syringospira prima
 Spiriferida - Ambocoeliidae
Echinocoelia youngstownensis
 Orthida - Schizophoriidae
"Schizophoria australis" = Schizophoria (Schizophoria) australis
"Schizophoria australis" = Schizophoria (Schizophoria) australis Kindle 1909
 Rhynchonellida - Rhynchotetradidae
Paraphorhynchus jeffersonense, Paraphorhynchus madisonense, Paraphorhynchus threeforksense
 Rhynchonellida - Trigonirhynchiidae
"Camarotoechia sobrina" = Ptychomalotoechia sobrina
"Camarotoechia sobrina" = Ptychomalotoechia sobrina Stainbrook 1947
 Rhynchonellida - Leiorhynchidae
Basilicorhynchus ventricosum
 Rhynchonellida - Petasmariidae
Shumardella dunbarensis
 Athyridida - Athyrididae
Cleiothyridina devonica
Stenolaemata
 Rhabdomesida - Rhabdomesidae
Rhabdomeson sp. n. sp.
Rhabdomeson sp. n. sp.
Rhabdomeson n. sp. A and Rhabdomeson n. sp. B
 Rhabdomesida - Rhomboporidae
Rhombopora sp. n. sp.
Rhombopora sp. n. sp. Meek 1872
Rhombopora n. sp.A
 Trepostomida - Atactotoechidae
Leptotrypella sp. n. sp.
Leptotrypella sp. n. sp. Vinassa de Regny 1921
Leptotrypella n. sp. A
Cephalopoda
 Goniatitida - Prolobitidae
Raymondiceras simplex
Raymondiceras simplex Raymond 1909 ammonite
 Goniatitida - Tornoceratidae
Tornoceras crebiseptum
 Clymeniida - Platyclymeniidae
Platyclymenia sp., Platyclymenia sp. n. sp.
Platyclymenia sp. Hyatt 1884 ammonite
Platyclymenia sp. n. sp. Hyatt 1884 ammonite
Platyclymenia n. sp. A and Platyclymenia n. sp. B