Johnson point, 1: Early/Lower Pleistocene, North Carolina
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Bivalvia
- Arcida
- Arcidae
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Anadara aequicostata
(Conrad 1845)
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2.5 %-individuals | |||||||||
| Represented mostly by juveniles | ||||||||||
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Bivalvia
- Ostreida
- Ostreidae
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Ostrea sculpturata
Conrad 1840
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4.4 %-individuals | |||||||||
| recombined as Conradostrea sculpturata | ||||||||||
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Bivalvia
- Nuculanida
- Nuculanidae
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Nuculana acuta
(Conrad 1832)
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4.9 %-individuals | |||||||||
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Gastropoda
- Heterostropha
- Pyramidellidae
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Boonea seminuda
(Adams 1839)
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27.0 %-individuals | |||||||||
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Gastropoda
- Neogastropoda
- Columbellidae
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Anachis lafresnayi
(Fischer and Bernardi 1857)
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1.7 %-individuals | |||||||||
| recombined as Cotonopsis (Cotonopsis) lafresnayi | ||||||||||
| var. | ||||||||||
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Anachis obesa
(Adams 1845)
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1.1 %-individuals | |||||||||
| recombined as Parvanachis obesa | ||||||||||
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Gastropoda
- Neogastropoda
- Nassariidae
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Nassarius albus
Say 1826
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1.0 %-individuals | |||||||||
| replaced by Nassarius antillarum | ||||||||||
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Gastropoda
- Neotaenioglossa
- Calyptraeidae
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Crepidula fornicata
(Linnaeus 1758)
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46.1 %-individuals | |||||||||
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Thecostraca
- Balanomorpha
- Balanidae
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Balanus spp.
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8.0 %-individuals | |||||||||
| see common names | ||||||||||
Geography
| Country: | United States | State/province: | North Carolina |
| Coordinates: | 35.0° North, 77.0° West (view map) | ||
| Paleocoordinates: | 35.1° North, 76.5° West | ||
| Basis of coordinate: | estimated from map | ||
| Geographic resolution: | outcrop |
Time
| Period: | Quaternary | Epoch: | Pleistocene |
| 10 m.y. bin: | Cenozoic 6 | ||
| Key time interval: | Early/Lower Pleistocene | ||
| Age range of interval: | 2.58000 - 0.77400 m.y. ago |
Stratigraphy
| Formation: | James City |
| Stratigraphic resolution: | group of beds |
Lithology and environment
| Primary lithology: | fine mudstone |
| Lithology description: a lower fine-grained fossiliferous mudstone | |
| Environment: | shallow subtidal indet. |
| Glacial or sequence phase: | interglacial |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils,mesofossils |
| Preservation of anatomical detail: | good |
| Abundance in sediment: | abundant |
| Articulated whole bodies: | some |
| Associated major elements: | many |
| Disassociated major elements: | many |
| Disassociated minor elements: | some |
| Size sorting: | poor |
| Temporal resolution: | time-averaged |
| Spatial resolution: | autochthonous |
Collection methods and comments
| Collection excludes: | some genera |
| Collection methods: | bulk,sieve,field collection |
| Minimum sieve size: | 2.000 |
| Reason for describing collection: | paleoecologic analysis |
| Collection method comments: We sampled the biostrome and overlying bivalve-rich shell bed by surface picking, and by collecting bulk samples of each type of bedding unit at one site where material was newly exposed and unweathered. Each one-liter sample was washed on a sieve with 2 mm openings; fossils separated from matrix were identified to species if possible, counted, examined for epi- and endobionts, and the dominant species were measured to estimate their size-frequency. More than 17,400 specimens belonging to approximately 80 species, mostly of small mollusks, were recovered in this way. Specimen counts were corrected to reflect original numbers of skeletonized organisms (e.g. 1 gas- tropod apical fragment = 1 individual, 1 bivalve beak fragment = 4 individual, 1 balanid side plate = Q individual, etc.). | |
| Taxonomic list comments:Any species with below .5% abundance was not listed | |
Metadata
| Also known as: | JP-1 | ||
| Database number: | 211029 | ||
| Authorizer: | N. Heim | Enterer: | C. Lombardi |
| Modifier: | C. Lombardi | ||
| Created: | 2020-06-23 23:24:14 | Last modified: | 2020-06-25 14:03:18 |
| Access level: | the public | Released: | 2020-06-23 23:24:14 |
| Creative Commons license: | CC BY | ||
Reference information
Primary reference:
| 72890. | W. Miller and J. R. DuBar. 1988. Community replacement of a Pleistocene Crepidula biostrome. Lethaia 21(0024-1164):67-78 [N. Heim/C. Lombardi] |