Where: Charles County, Maryland (38.4° N, 77.0° W: paleocoordinates 38.8° N, 61.1° W)
• coordinate based on nearby landmark
• outcrop-level geographic resolution
When: Woodstock Member (Nanjemoy Formation), Ypresian (56.0 - 47.8 Ma)
• STRATIGRAPHIC RELATIONS: From the Woodstock Greensand Marl Mbr of the Nanjemoy Fm, Pamunkey Gp. Eocene, according to Miller (1947); Early Eocene, according to Ward (1985). STRATIGRAPHIC POSITION: From upper part of member.
• bed-level stratigraphic resolution
Environment/lithology: transition zone or lower shoreface; poorly lithified, glauconitic, micaceous, black, green, silty sandstone
• ENVIRONMENT: The larger, diverse molluscan fauna in the Woodstock, compared with the nondiverse Potapaco assemblages, suggest a return to more open-marine, shallow-shelf conditions (Ward, 1985). The foraminiferal assemblages indicate an inner sublittoral paleoenvironment with water depths of about 20-40 m during deposition of the lower and middle parts of the unit and an inner sublittoral (40-60 m) environment with firm, sandy substrates during deposition of the upper part. The abundance of Turrilina and Fursenkoina, which are among the predominant benthic genera in the middle part of the unit, suggests waters containing lower than normal dissolved oxygen. The somewhat coarser, much more lignitic, pebbly sands of the Woodstock, the relatively shallow water depths, and the microfauna suggest a perideltaic environment. Dinocyst assemblages throughout the Nanjemoy in the Haynesville cores are dominated by peridiniacean taxa and thus represent predominantly estuarine to inner neritic environments.
• SPECIFIC LITHOLOGY: Sand, olive-black (5 Y 2/1), very fine, silty, micaceous, well-sorted, very glauconitic; numerous well-preserved mollusks; upper contact sharp and burrowed; burrows extend as much as 3 feet downward. LITHIFICATION: Poorly ;ithified, based on facies description and figured specimens.
Size class: macrofossils
Collection methods: COLLECTORS: Unknown collector. REPOSITORY: Johns Hopkins University.
Primary reference: W. B. Clark and G. C. Martin. 1901. Mollusca. Maryland Geological Survey, Eocene 122-203 [M. Clapham/M. Clapham]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 81880: authorized by Austin Hendy, entered by Austin Hendy on 17.07.2008, edited by Mark Uhen and Matthew Clapham
Creative Commons license: CC BY (attribution)
• COVERAGE: Limited to Nautiloidea described in primary publication. NOMENCLATURE: Authoritative publication with modern nomenclature and species-resolution identifications.
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