Muddy Creek Plesiosaur Site (Lower Horizon) (Cretaceous of the United States)

Where: Kane County, Utah (37.3° N, 112.7° W: paleocoordinates 39.0° N, 75.4° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Sciponoceras gracile ammonoid zone, Tropic Shale Formation, Cenomanian (100.5 - 93.9 Ma)

• bed-level stratigraphic resolution

Environment/lithology: marine; concretionary, gray lime mudstone

• ammonites found in concretions, bivalves "near the margin of the concretions"
• medium gray, non-septarian, spheroidal, micrite concretions

Preservation: concretion

Primary reference: D. D. Gillette, M. C. Hayden, and A. L. Titus. 1999. Occurrence and biostratigraphic framework of a plesiosaur from the Upper Cretaceous Tropic Shale of southwestern Utah. Utah Geological Survey Miscellaneous Publication 99-1:269-273 [J. Alroy/J. Alroy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 5608: authorized by John Alroy, entered by John Alroy on 31.10.1999

Creative Commons license: CC BY (attribution)

Taxonomic list

Bivalvia
 Myalinida - Inoceramidae
Inoceramus pictus Sowerby 1829 clam
Gastropoda
 Sorbeoconcha - Turritellidae
Turritella whitei turret shell
Cephalopoda
 Ammonitida - Placenticeratidae
Placenticeras cumminsi Cragin 1893 ammonite
 Ammonitida - Acanthoceratidae
Metoicoceras geslinianum d'Orbigny 1841 ammonite
 Ammonitida - Anisoceratidae
Allocrioceras annulatum ammonite
based on collection of Swensen 1962
 Ammonitida - Baculitidae
Sciponoceras gracile Shumard 1860 ammonite