St. George Dinosaur Discovery Tracksite (Main Track Layer): Hettangian, Utah
collected by S. Johnson, A. Milner 2000-

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
unclassified
Plantae indet. Haeckel 1866
Kirkland et al. 2002
similar to water lily but presumably unrelated
Equisetopsida - Araucariaceae
Pagiophyllum sp. Heer 1881
Milner et al. 2006
SGDS.491
unclassified
Characichnos sp. Whyte and Romano 2001
Milner et al. 2006
Reptilia - Grallatoridae
Eubrontes sp. Hitchcock 1845
SGDS.9
    = Eubrontes giganteus Hitchcock 1836
Hunt and Lucas 2006
Grallator sp. Hitchcock 1858
SGDS.74, SGDS.361, SW.90
    = Grallator cursorius Hitchcock 1858
Hunt and Lucas 2006
Reptilia - Batrachopodidae
cf. Batrachopus sp. Hitchcock 1845
Milner et al. 2006
Batrachopus sp. Hitchcock 1845
Kirkland et al. 2002
    = Batrachopus deweyi Hitchcock 1843
Hunt and Lucas 2006
Gastropoda
Gastropoda indet. Cuvier 1795
Kirkland et al. 2002
trail
unclassified
cf. Palaeophycus sp. Hall 1847
Milner et al. 2006
Scoyenia sp. White 1929
Milner and Lockley 2006
see common names

Geography
Country:United States State/province:Utah County:Washington
Coordinates: 37.1° North, 113.5° West (view map)
Paleocoordinates:17.3° North, 52.8° West
Basis of coordinate:estimated from map
Altitude:2612 feet
Geographic resolution:local area
Time
Period:Jurassic Epoch:Early/Lower Jurassic
Stage:Hettangian 10 m.y. bin:Jurassic 1
Key time interval:Hettangian
Age range of interval:201.40000 - 199.50000 m.y. ago
Stratigraphy
Geological group:Glen Canyon Formation:Moenave Member:Whitmore Point
Local section:St. George Local bed:53 m
Local order:bottom to top
Stratigraphic resolution:bed
Stratigraphy comments: among the lowest of the 25 regional track-bearing layers, just below the Top Surface; 53 m above base of formation

Most of the Moenave Formation is the Dinosaur Canyon Member. In the Moenave type section, near Tuba City, Arizona, all of the Moenave section is Dinosaur Canyon Member, as it is throughout the Moenave outcrop belt along the Echo Cliffs and Ward's Terrace of northern Arizona. However, north of the Grand Canyon in Arizona and in southwestern Utah, the upper part of the Moenave Formation is lacustrine strata. These strata are the Whitmore Point Member.
Lucas et al. (2011: Palaeo3 302: 194-205) proposed, on the basis of multiple lines of biostratigraphic evidence, that the Triassic–Jurassic boundary is placed within the middle part of the Whitmore Point Member of the Moenave Formation where this member is present, and high in the Dinosaur Canyon Member elsewhere. The "Whitmore Point assemblage" of vertebrate taxa, earliest Jurassic (Hettangian) in age. The underlying "Dinosaur Canyon assemblage", is latest Triassic (Rhaetian) in age.

Lucas et al. (2011) noted that the St George tracksite is of latest Triassic age, rather than earliest Jurassic as initially reported
Lithology and environment
Primary lithology:desiccation cracks,current ripples,fine sandstone
Secondary lithology: mudstone
Includes fossils?Y
Lithology description: "3-foot-thick sandstone layer overlying a mudstone layer"; "well-sorted, fine-grained sandstone bed"
Environment:lacustrine indet.
Geology comments: mudflats and beaches surrounding ancient lake, forming an oasis during deposition of the Wingate erg to the NE, transitioning to "offshore" facies in the same layer at the DSQ sites.
Taphonomy
Modes of preservation:body,cast,mold/impression,trace
Degree of concentration:concentrated
Size of fossils:macrofossils
Spatial orientation:life position
Preservation of anatomical detail:excellent
Associated major elements:some
Disassociated major elements:some
Temporal resolution:snapshot
Spatial resolution:autochthonous
Collection methods and comments
Collection methods:selective quarrying,surface (in situ),field collection,observed (not collected)
Reason for describing collection:general faunal/floral analysis
Collectors:S. Johnson, A. Milner Collection dates:2000-
Collection method comments: discovered by Sheldon Johnson
Metadata
Also known as:Johnson farm, SGDS, MTL, DSQ1, DSQ2, Dinosaur Swim Quarry 1, 2
Database number:56131
Authorizer:M. Carrano Enterer:M. Carrano
Modifier:G. Varnham Research group:vertebrate
Created:2005-11-11 19:02:32 Last modified:2022-04-26 05:36:06
Access level:the public Released:2005-11-11 19:02:32
Creative Commons license:CC BY
Reference information

Primary reference:
50513. M. Hayden. 2000. Important dinosaur track discovery in St. George. Utah Geological Survey Notes 32(3):9 [M. Carrano/M. Carrano]

Secondary references:

69025 L. Alcalá, M. G. Lockley, A. Cobos, L. Mampel, and R. Royo-Torres. 2016. Evaluating the dinosaur track record: an integrative approach to understanding the regional and global distribution, scientific importance, preservation, and management of tracksites. In P. L. Falkingham, D. Marty, & A. Richter (eds.), Dinosaur Tracks: The Next Steps 100-116 [M. Carrano/M. Carrano]
66081 A. P. Hunt and S. G. Lucas. 2006. The significance of the St. George Dinosaur Discovery Site at Johnson Farm: a Jurassic Konzentrat-Ichnolagerstätte, Utah, U.S.A. In J. D. Harris, S. G. Lucas, J. A. Spielmann, M. G. Lockley, A. R. C. Milner, J. I. Kirkland (eds.), The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin 37:282-288 [M. Carrano/M. Carrano/P. Wagner]
15120ETE J. I. Kirkland, M. G. Lockley, and A. R. Milner. 2002. The St. George dinosaur tracksite. Utah Geological Survey Notes 34(3):4-5, 12 [M. Carrano/M. Carrano/M. Carrano]
66101 J. I. Kirkland and A. R. C. Milner. 2006. The Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, St. George, southwestern Utah. In J. D. Harris, S. G. Lucas, J. A. Spielmann, M. G. Lockley, A. R. C. Milner, J. I. Kirkland (eds.), The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin 37:289-309 [M. Carrano/M. Carrano/P. Wagner]
16803ETE A. R. Milner, M. G. Lockley, J. I. Kirkland, P. Bybee, and D. Mickelson. 2004. St. George tracksite, southwestern Utah: remarkable Early Jurassic (Hettangian) record of dinosaurs walking, swimming, and sitting provides a detailed view of the paleoecosystem along the shores of Lake Dixie. Journal of Vertebrate Paleontology 24(3, suppl.):94A [M. Carrano/M. Carrano/J. Alroy]
78695 A. R. C. Milner, T. A. Birthisel, J. I. Kirkland, B.H. Breithaupt, N. A. Matthews, M. G. Lockley, V. L. Santucci, S. Z. Gibson, D. D. DeBlieux, M. Hurlbut, J. D. Harris and P. E. Olsen. 2011. Tracking Early Jurassic dinosaurs across southwestern Utah and the Triassic-Jurassic transition. In J. W. Bonde & A. R. C. Milner (ed.), Field Trip Guide Book, 71st Annual Meeting of the Society of Vertebrate Paleontology Paris Las Vegas, Las Vegas, Nevada, November 2-5, 2011. Nevada State Museum Paleontological Papers 1:1-107 [M. Carrano/M. Carrano/M. Carrano]
38715 A. R. C. Milner, J. D. Harris, M. G. Lockley, J. I. Kirkland, and N. A. Matthews. 2009. Bird-like anatomy, posture, and behavior revealed by an Early Jurassic theropod dinosaur resting trace. PLoS One 4(3):e4591:1-14 [M. Carrano/M. Carrano/M. Carrano]
38723 A. R. C. Milner, J. I. Kirkland, and S. Z. Spears. 2007. Colorado Plateau Coring Project (CPCP) workshop 2007. Field trip, November 15, 2007. 1-24 [M. Carrano/M. Carrano]
78694 A. R. C. Milner and J. I. Kirkland. 2007. The case for fishing dinosaurs at the St. George Dinosaur Discovery Site at Johnson Farm. Utah Geological Survey Notes 39(3):1-3 [M. Carrano/M. Carrano]
38719 A. R. C. Milner, M. G. Lockley, and S. B. Johnson. 2006. The story of the St. George Dinosaur Discovery Site at Johnson Farm: an important new Lower Jurassic dinosaur tracksite from the Moenave Formation of southwestern Utah. In J. D. Harris, S. G. Lucas, J. A. Spielmann, M. G. Lockley, A. R. C. Milner, & J. I. Kirkland (eds.), The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin 37:329-345 [M. Carrano/M. Carrano/M. Carrano]
38721 A. R. C. Milner, M. G. Lockley, and J. I. Kirkland. 2006. A large collection of well-preserved theropod dinosaur swim tracks from the Lower Jurassic Moenave Formation, St. George, Utah. In J. D. Harris, S. G. Lucas, J. A. Spielmann, M. G. Lockley, A. R. C. Milner, & J. I. Kirkland (eds.), The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin 37:315-328 [M. Carrano/M. Carrano/M. Carrano]
51460 A. R. C. Milner and M. G. Lockley. 2006. History, geology and paleontology: St. George Dinosaur Discovery Site at Johnson Farm, Utah. In R. E. Reynolds (ed.), Making Tracks Across the Southwest: The 2006 Desert Symposium 35-48 [M. Carrano/M. Carrano]
69059 A. R. C. Milner and M. G. Lockley. 2016. Dinosaur swim track assemblages: characteristics, contexts, and ichnofacies implications. In P. L. Falkingham, D. Marty, & A. Richter (eds.), Dinosaur Tracks: The Next Steps 152-180 [M. Carrano/M. Carrano]