346 Harris et al., eds., 2006, The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin 37. THE EARLY JURASSIC (HETTANGIAN) LDS DINOSAUR TRACKSITE FROM THE MOENAVE FORMATION IN ST. GEORGE, UTAH JESSICA A.J. WILLIAMS 1 , ANDREW R.C. MILNER 2 AND MARTIN G. LOCKLEY 3 1 Division of Geosciences, Southern Utah University, 351 W. Center St., Cedar City, UT 84720, E-mail: jajw77@hotmail.com; 2 St. George Dinosaur Discovery Site at Johnson Farm, 2180 East Riverside Dr., St George, UT 84790, E-mail: amilner@sgcity.org; 3 Dinosaur Tracks Museum, University of Colorado at Denver, PO Box 173364, Denver, CO, 80217, E-mail: mlockley@carbon.cudenver.edu Abstract—Early Jurassic (early Hettangian) dinosaur tracks, as well as invertebrate traces and bone material, are preserved in marginal lacustrine deposits of the Whitmore Point Member of the Moenave Formation near the St. George Dinosaur Discovery Site at Johnson Farm (SGDS), within St. George city limits in southwestern Utah. A laterally extensive, 30 cm thick, fine-grain sandstone bed deposited along the shores of ancient Lake Dixie contains hundreds of theropod dinosaur tracks, rare crocodylomorph tracks (cf. Batrachopus), Skolithos burrows, weath- ered bone fragments, and semionotid fish scales. INTRODUCTION In February, 2000, Dr. Sheldon Johnson discovered abundant, well-preserved dinosaur tracks in the Lower Jurassic Moenave Forma- tion in southwestern Utah. During the construction of a museum directly over the original Johnson discovery site, another tracksite was discov- ered on property belonging to the Church of Jesus Christ of Latter Day Saints (LDS) northwest of the museum and Riverside Drive. This site was designated the LDS Tracksite (Fig. 1). The track-bearing unit is approximately 63 m above the base of the Moenave Formation and has yielded more than 200 in situ theropod dinosaur tracks to date. Abundant dinosaur traces at and around the SGDS record diverse dinosaur behav- iors on mudflats and beaches surrounding ancient Lake Dixie (Milner et al., this volume a, b). This lake was an oasis during deposition of the Moenave red beds and the time-equivalent Wingate Erg to the east and northeast. Grallator tracks dominate the LDS Tracksite, with only a single Eubrontes track recorded thus far. The track-bearing layer contains isolated fish scales and bone fragments and was extensively bioturbated by invertebrates (Lucas et al., this volume) prior to the formation of dinosaur tracks; the surface was subsequently desiccated, forming abun- dant mudcracks. Track orientations are more or less random. Several areas of this track surface are heavily trampled, making it difficult to distinguish indi- vidual footprints. This track-bearing layer represents a lacustrine regres- sion where theropods were moving to and from the shoreline across a wide mudflat. This mudflat would have been situated on the south side of the Lake Dixie shoreline when these footprints were formed. STRATIGRAPHY AND AGE The LDS Tracksite is situated within the 7.64 m thick “middle sandstone-dominated interval” of Kirkland and Milner (this volume) in the Whitmore Point Member of the Moenave Formation (Fig. 2). This middle sandstone-dominated interval comprises interbedded, reddish- brown sandstone and mudstone, similar in appearance to the upper part of the Dinosaur Canyon Member. Unlike the latter, however, these sand- stones contain less well-preserved tracks, although invertebrate bur- rows, fish scales, bones, and coprolites are very abundant (Milner and Lockley, 2006; Lucas et al., this volume). The laterally extensive, LDS track-bearing unit is a bed measuring about 30 cm in thickness consisting of fine-grained sandstone and situated approximately 63 m above the base of the Moenave Formation. Both the uppermost part of the Dinosaur Canyon and the Whitmore Point members are confirmed as Early Jurassic (Hettangian) in age based on track types present at the SGDS (Milner et al., this volume a). Fur- ther biostratigraphic confirmation comes from pollen studies (Litwin, 1986; Cornet and Waanders, this volume) and magnetostratigraphy (Molina-Garza et al., 2003; Donohoo-Hurley et al., 2006). METHODS Initial excavation of the LDS Tracksite occurred with the assis- tance of Dixie State College Elderhostel groups, SGDS volunteers, and Utah Friends of Paleontology members (Fig. 3A). An elongate strip of FIGURE 1. Locality maps. A, Overview locality map of Utah (inset) and the St. George area, showing the SGDS study area. B, Locality map of the SGDS study area showing the 17 numbered localities. Locality #17 is the location of the LDS Tracksite, locality #11 the Mall Drive Tracksite (now destroyed), and locality #1 the SGDS museum building and initial Sheldon Johnson discovery site.