Threeforks Shale, Jefferson Island Co., Montana (measured section 5 of author) (Devonian of the United States)

Where: Jefferson Island County, Montana (45.9° N, 111.8° W: paleocoordinates 14.9° 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; yellow shale

• 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

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 6972: 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
Strophomenata
 Productida - Productidae
Leioproductus coloradensis, Leioproductus montanensis
Rhynchonellata
 Orthida - Schizophoriidae
"Schizophoria australis" = Schizophoria (Schizophoria) australis
"Schizophoria australis" = Schizophoria (Schizophoria) australis Kindle 1909
 Rhynchonellida - Leiorhynchidae
Basilicorhynchus ventricosum
 Rhynchonellida - Trigonirhynchiidae
"Camarotoechia sobrina" = Ptychomalotoechia sobrina
"Camarotoechia sobrina" = Ptychomalotoechia sobrina Stainbrook 1947
 Rhynchonellida - Petasmariidae
Shumardella dunbarensis
 Rhynchonellida - Rhynchotetradidae
Paraphorhynchus madisonense, Paraphorhynchus ashboughense
Paraphorhynchus ashboughense
Paraphorhynchus ashboughense n. var.
 Athyridida - Athyrididae
Cleiothyridina devonica
 Spiriferida - Cyrtospiriferidae
Syringospira prima
 Spiriferida - Mucrospiriferidae
Eleutherokomma raymondi
Cephalopoda
 Clymeniida - Platyclymeniidae
"Platyclymenia polypleura" = Pleuroclymenia americana, Platyclymenia sp. n. sp.
"Platyclymenia polypleura" = Pleuroclymenia americana Raymond 1907 ammonite
Platyclymenia sp. n. sp. Hyatt 1884 ammonite
P. n. sp. B
 Goniatitida - Tornoceratidae
Tornoceras crebiseptum