Muirkirk, Arundel (Cretaceous of the United States)

Where: Prince George's County, Maryland (39.1° N, 76.9° W: paleocoordinates 33.0° N, 29.5° W)

• coordinate stated in text

• local area-level geographic resolution

When: Arundel Clay Formation (Potomac Group), Early/Lower Aptian (125.5 - 122.5 Ma)

• Originall described as "Potomac Formation" and "Upper Jurassic"; now considered early-mid Aptian

• member-level stratigraphic resolution

Environment/lithology: lacustrine; gray, red claystone

• "variegated red and gray clays"

Size class: macrofossils

Collected by J. B. Hatcher, A. Bibbins in 1887-1894; reposited in the USNM

Collection methods: quarrying, mechanical,

Primary reference: O. C. Marsh. 1888. Notice of a new genus of Sauropoda and other new dinosaurs from the Potomac Formation. American Journal of Science 35:89-94 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 28432: authorized by Matthew Carrano, entered by Matthew Carrano on 13.02.2003, edited by Roger Benson

Creative Commons license: CC BY (attribution)

Taxonomic list

Reptilia
 Testudines -
Glyptops caelatus n. sp.2 Hay 1908 turtle
USNM 1930, 1939: The most important fragment consists of the right first costal, a part of the first and most of the second peripherals. There is also a part of a costal situated further back in the carapace. These bear the number 1930, and belonged doubtless to one individual. There is present also a hinder peripheral and a first right peripheral which have the number 1939. There are also two fragments of costals of a young individual, one of which shows the rib-head
 Saurischia -
Pleurocoelus altus n. sp., Pleurocoelus nanus n. gen. n. sp.
Pleurocoelus altus n. sp. Marsh 1888 sauropod
Pleurocoelus nanus n. gen. n. sp. Marsh 1888 sauropod
 Avetheropoda -
Coelurus gracilis n. sp., "Ornithomimus affinis n. sp." = Coelosaurus affinis1
Coelurus gracilis n. sp. Marsh 1888 coelurosaur
USNM 4973, 8444–8445
"Ornithomimus affinis n. sp." = Coelosaurus affinis1 Gilmore 1920 ornithomimosaur
 Saurischia -
Allosaurus medius n. sp. Marsh 1888 tetanuran
USNM 4972, 3446, 5693, 8447, 8502–8504
 Ornithischia -
Priconodon crassus n. gen. n. sp.
Priconodon crassus n. gen. n. sp. Marsh 1888 ornithischian