Marshalltown Formation (Delaware) fauna (Cretaceous of the United States)

Also known as Marshalltown Formation (St Georges) fauna

Where: New Castle County, Delaware (39.6° N, 75.7° W: paleocoordinates 38.8° N, 44.9° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Marshalltown Formation, Campanian (83.6 - 72.1 Ma)

• Underlain by Englishtown Formation (burrowed quartz sand), and overlain by Mount Laurel Sand (burrowed quartz sand) - collection 35049.

• formation-level stratigraphic resolution

Environment/lithology: transition zone or lower shoreface; lithified, burrowed, glauconitic, shelly/skeletal, brown, silty, carbonaceous sandstone

• See Owens and Minard (1970) for detailed geologic data on geology of Chesapeake and Delaware Canal area. "Marshalltown was deposited in a shelf to lower shoreface environment"
• "Marshalltown Formation is a dark greenish-gray, very fine to fine, clayey, glauconitic sand"; 3-4 m thick.

Size class: macrofossils

Preservation: mold/impression, replaced with calcite, replaced with phosphate

Reposited in the AMNH, UNSM

Collection methods: salvage, quarrying,

• Collections by local amateur paleontology organisationsl collections from spoil heaps along canal west of Saint Georges, DE

Primary reference: W. J. Kennedy and W.A. Cobban. 1997. Upper Campanian (Upper Cretaceous) ammonites from the Marshalltown Formation-Mount Laurel boundary beds in Delaware. Journal of Paleontology 71(1):62-73 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 35048: authorized by Austin Hendy, entered by Austin Hendy on 28.10.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

• Compilation of taxonomic descriptions of ammonoids, and other taxa mentioned in text
Bivalvia
 Arcida - Cucullaeidae
Cucullaea sp. Lamarck 1801 clam
 Ostreida - Gryphaeidae
 Ostreida - Ostreidae
"Ostrea (Agerostrea) falcata" = Agerostrea falcata
"Ostrea (Agerostrea) falcata" = Agerostrea falcata Morton 1827 oyster
 Cardiida - Veneridae
Cyprimeria sp. Conrad 1864 venus clam
 Cardiida - Cardiidae
Cardium sp. Linnaeus 1758 cockle
 Trigoniida - Trigoniidae
Trigonia sp. Bruguière 1789 clam
Cephalopoda
 Ammonitida - Pachydiscidae
Menuites portlocki Sharp 1855 ammonite
Listed as "Menuites portlocki complexus"
Pachydiscus (Pachydiscus) sp. Zittel 1884 ammonite
 Ammonitida - Baculitidae
Baculites ovatus Say 1820 ammonite
 Ammonitida - Nostoceratidae
Didymoceras binodosum Kennedy and Cobban 1993 ammonite