Cisco Mammal Quarry, OMNH V1728 (Jurassic of the United States)

Where: Grand County, Utah (39.0° N, 109.3° W: paleocoordinates 35.6° N, 56.6° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Brushy Basin Member (Morrison Formation), Early/Lower Tithonian (150.8 - 145.0 Ma)

• "coarse stratigraphic placement of the CMQ is likely low in the Brushy Basin Member"

•Davis et al. 2022: Twenty-two single zircons were dissolved and analyzed by CA-ID-TIMS methods (see SOM for details on dating methodology). The weighted mean age of 151.50 ± 0.28 Ma (Tithonian, Late Jurassic) is interpreted as the best esti- mate of the volcanic ashfall age of the four youngest zir- con crystals. The presence of rounded detrital grains and slightly older euhedral zircons, however, implies that even the youngest ages could be from detrital grains; as a result, the weighted mean represents a maximum depositional age. This age places the Cisco Mammal Quarry approximately 1 million years younger than Quarry 9 at Como Bluff (152.51 ± 0.47 Ma, Trujillo et al. 2015), and approximately 0.5 million years younger than the Main Callison Quarry at the Fruita Paleontological Area (152.0 ± 0.3 Ma, Foster et al. 2017). However, it should be noted that the ranges of these ages do overlap leaving open the possibility that CMQ and FPA are contemporaneous.

• bed-level stratigraphic resolution

Environment/lithology: crevasse splay; mudstone and sandstone

• There are distinct similarities between the lithology of the CMQ and what Kirkland (2006) described as the “drab floodplain facies” at the Fruita Paleontological Area (FPA), located approximately 48 km ENE of the CMQ. This facies displays intervals of gray mudstone with a lack of sedimentary structures interbedded with thin sandstone beds. Barite nodules occur in this facies, suggesting the occasional presence of standing water. Kirkland (2006) interpreted the strata of this facies to be deposited in smaller crevasse splays occurring seasonally on medium-sized river channels, and this interpretation is tentatively applied to the strata of the CMQ as well.
• "The locality is at the top of a rounded, pale-gray knob ... The hill preserves an irregular sequence of mudstone and thinner sandstone beds, mostly of uniform pale color. The sandstone beds are more resistant to weathering and appear rounded in profile when exposed. ...the beds seem to lack sedimentary structures and are strongly indurated. The mudstone beds are smectitic and calcareous, containing a substantial proportion of fine- to very fine grained sand. Small flecks of biotite are present, and barite nod-ules are common with some as large as 10 cm. Bone has been found at low density throughout much of the worked section, and does not appear to be concentrated at a particular horizon or horizons."

Size classes: macrofossils, mesofossils

Collection methods: quarrying, surface (float), surface (in situ),

Primary reference: B. M. Davis, R. L. Cifelli, and G. W. Rougier. 2018. A preliminary report of the fossil mammals from a new microvertebrate locality in the Upper Jurassic Morrison Formation, Grand County, Utah. Geology of the Intermountain West 5:1-8 [P. Holroyd/P. Holroyd/M. Carrano]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 191718: authorized by Patricia Holroyd, entered by Patricia Holroyd on 10.02.2018, edited by Grace Varnham

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
unclassified
  -
Parviraptoridae indet.
Osteichthyes
 Osteichthyes -
Osteichthyes indet.
Osteichthyes indet. Huxley 1880 bony fish
Reptilia
 Archosauria -
Archosauria indet.
Archosauria indet. Cope 1869 archosaur
 Ornithischia - Heterodontosauridae
? Fruitadens sp.
? Fruitadens sp. Butler et al. 2010 heterodontosaurid
 Squamata -
Squamata indet., Serpentes indet.
Squamata indet. Oppel 1811 squamates
Osteichthyes
 Cynodontia -
Morganucodonta indet.
Morganucodonta indet. Kermack et al. 1973 mammaliaform
 Morganucodonta -
Cifellilestes ciscoensis n. gen. n. sp.
Cifellilestes ciscoensis n. gen. n. sp. Davis et al. 2022 mammaliaform
Holotype: OMNH 80538, right skull fragment preserving partial palate and snout, and postcanine dentition; OMNH 69352, left skull fragment preserving partial palate and snout, and postcanine dentition
Mammalia
 Multituberculata -
Multituberculata indet., Glirodon grandis
Multituberculata indet. multituberculate
Glirodon grandis Engelmann and Callison 1999 multituberculate
  -
Fruitafossor windscheffeli
Fruitafossor windscheffeli Luo and Wible 2005 mammal
 Theriamorpha -
Trechnotheria indet.
Trechnotheria indet. McKenna 1975 mammal
 Theriamorpha - Dryolestidae
Dryolestes priscus
Dryolestes priscus Marsh 1878 mammal
 Theriamorpha - Paurodontidae
Paurodontidae indet.
Paurodontidae indet. Marsh 1887 mammal
 Eutriconodonta -
Eutriconodonta indet.
Eutriconodonta indet. Kermack et al. 1973 mammal