Threeforks Shale, Jefferson Island Co., Montana (measured section 4 of author): Middle Famennian, Montana
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Craniata
- Craniida
- Craniidae
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Petrocrania sp.
Raymond 1910
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Strophomenata
- Orthotetida
- Schuchertellidae
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Schuchertella sp.
Girty 1904
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Rhynchonellata
- Spiriferinida
- Syringothyrididae
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Syringothyris cf. typus
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Rhynchonellata
- Orthida
- Rhipidomellidae
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Rhipidomella cf. newalbanensis
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| Rhipidomella cf. vanuxemi newalbanensis | ||||||||||
| see common names | ||||||||||
Geography
| Country: | United States | State/province: | Montana | County: | Jefferson Island |
| Coordinates: | 45.9° North, 111.9° West (view map) | ||||
| Paleocoordinates: | 14.8° South, 46.6° West | ||||
| Basis of coordinate: | based on nearby landmark | ||||
| Geographic resolution: | outcrop |
Time
| Period: | Devonian | Epoch: | Late/Upper Devonian |
| Stage: | Famennian | 10 m.y. bin: | Devonian 5 |
| *Period: | Late/Upper Devonian | ||
| Key time interval: | Middle Famennian | Zone: | Platyclymenia |
| Age range of interval: | 368.50000 - 365.30000 m.y. ago | ||
| * legacy (obsolete) database fields | |||
Stratigraphy
| Formation: | Three Forks Shale | ||||
| Stratigraphic resolution: | formation | ||||
| Stratigraphy comments: 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] | |||||
Lithology and environment
| Primary lithology: | planar lamination,red or brown,yellow "shale" |
| Secondary lithology: | siltstone |
| Lithology description: 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 upper shales from a horizon identified as a siltstone | |
| Environment: | marine indet. |
Taphonomy
| Modes of preservation: | body |
Collection methods and comments
| Collection methods: | surface (in situ),field collection |
| Reason for describing collection: | biostratigraphic analysis |
Metadata
| Database number: | 6979 | ||
| Authorizer: | A. Miller | Enterer: | K. Layou |
| Modifier: | J. Alroy | Research group: | marine invertebrate |
| Created: | 2000-04-18 12:13:06 | Last modified: | 2010-07-15 08:19:54 |
| Access level: | the public | Released: | 2000-11-20 13:53:33 |
| Creative Commons license: | CC BY |
Reference information
Primary reference:
| 438. | P. J. Renzetti. 1961. Fauna of the Threeforks Shale (Devonian) of Southwestern Montana. 1-342 [A. Miller/K. Layou/M. Uhen] |