USGS Mesozoic loc. 19183, north of Sun River area, Western Montana: Bajocian, Montana
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Bivalvia
- Pectinida
- Oxytomidae
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Meleagrinella curta
(Hall 1852)
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Oxytoma mclearni
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Bivalvia
- Pectinida
- Anomiidae
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Placunopsis sp.
Morris and Lycett 1853
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Bivalvia
- Arcida
- Cucullaeidae
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cf. Idonearca rockymontana
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| Idonearca? cf. I. rockymontana | ||||||||||
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Bivalvia
- Lucinida
- Lucinidae
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Lucina sp.
Bruguière 1797
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Bivalvia
- Trigoniida
- Trigoniidae
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Trigonia cf. trafalgarensis
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| see common names | ||||||||||
Geography
| Country: | United States | State/province: | Montana |
| Coordinates: | 48.2° North, 112.9° West (view map) | ||
| Paleocoordinates: | 40.2° North, 51.4° West | ||
| Basis of coordinate: | estimated from map | ||
| Geographic resolution: | small collection |
Time
| Period: | Jurassic | Epoch: | Middle Jurassic |
| Stage: | Bajocian | 10 m.y. bin: | Jurassic 4 |
| Key time interval: | Bajocian | ||
| Age range of interval: | 170.9 - 168.2 m.y. ago |
Stratigraphy
| Formation: | Sawtooth | Member: | Lower Sandstone | ||
| Stratigraphic resolution: | group of beds | ||||
| Stratigraphy comments: from 3 ft of siliceous limestone about 6.5 ft above base of Sawtooth formation in the lower member; the Lower Sandstone member is probably of Bajocian age | |||||
Lithology and environment
| Primary lithology: | lithified cherty/siliceous "limestone" |
| Environment: | marine indet. |
Taphonomy
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection methods: | field collection |
| Reason for describing collection: | biostratigraphic analysis |
| Museum repositories: | USGS |
| Collection method comments: collection was made by R. W. Imlay in 1944 | |
Metadata
| Database number: | 68824 | ||
| Authorizer: | M. Aberhan | Enterer: | S. Nurnberg |
| Modifier: | S. Nurnberg | Research group: | marine invertebrate |
| Created: | 2007-02-09 08:51:42 | Last modified: | 2007-02-10 05:16:16 |
| Access level: | the public | Released: | 2007-02-09 08:51:42 |
| Creative Commons license: | CC BY |
Reference information
Primary reference:
| 19843. | 1% | R. W. Imlay. 1962. Jurassic (Bathonian or Early Callovian) Ammonites from Alaska and Montana. Geological Survey Professional Paper 374-C:1-32 [M. Aberhan/S. Nurnberg] |