Drewry's Bluff clay balls (Cretaceous of the United States)

Where: Chesterfield County, Virginia (37.4° N, 77.4° W: paleocoordinates 31.6° N, 30.4° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Patuxent Formation (Potomac Group), Early/Lower Cretaceous (145.0 - 100.5 Ma)

• Brenner's pollen Zone I

• bed-level stratigraphic resolution

Environment/lithology: unlithified, conglomeratic sandstone and unlithified claystone

• The clayballs are embedded in a sand and gravel bed in the lower part of the exposure, 1-2 m above river level.

Size classes: mesofossils, microfossils

Reposited in the FMNH

Collection methods: bulk, chemical, peel or thin section, sieve,

• "Fossils were extracted from the sediments by sieving in water. After sieving the plant material was rinsed in HF, HCl, and water and air dried... Material for ultrastructural and anatomical studies was dehydrated in an ethanol-propylene oxide series, embedded in Epon and sectioned on an LKB Ultratome III ultramicrotome with a glass knife (sections 3 micrometers thick) or diamond knife (sections about 600 angstroms thick)." (Pedersen et al. 1993)

Primary reference: K. R. Pedersen, E. M. Friis, and P. R. Crane. 1993. Pollen organs and seeds with Decussosporites Brenner from Lower Cretaceous Potomac Group sediments of eastern USA. Grana 32:273-289 [H. Sims/J. Cassara/J. Cassara]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 36514: authorized by Hallie Sims, entered by Jason Cassara on 01.02.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Brenneria potomacensis n. gen. n. sp.
pollen organs
Pinopsida
 Pinales - Cheirolepidiaceae
Cycadopsida
 Cycadales -
Eucommiidites sp. Erdtman 1948 cycads
gymnospermous pollen
 Gymnospermophyta -
Decussosporites sp. Brenner 1963
bisaccate pollen