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Ornithopod Tracks 
Remarks These tracks are in the top of the Lower Glen Rose Formation, and were photographed by Keith Minor at an undisclosed locality (to protect the site) in Texas. These trackways occur throughout Texas, the best-known being the ones at Dinosaur Valley State Park, Glen Rose, Somervell County, TX. For additional information, see the references below. These tracks fit the description of Gypsichnites sp. of Langston, Jr. (see below), having thick, blunt, three-toed tracks. This suggests that the dinosaur that made it was an ornithopod, such as an iguanodontid (herbivore). We don't have enough information to get the ID down to Family or Genus. General Info Stratigraphic Occurrence - Upper Trinity Group, top of the Lower Glen Rose Formation of North and Central Texas
Age Presumably, the tracks occur at about the level of the Dinosaur Valley State Park tracks, being part of the megatrackway complex of Texas. According to Langston, Jr., the tracks at Dinosaur Valley occur ~6 feet below the Caryocorbula martinae (Whitney) bivalve zone that separates the Glen Rose Limestone into the lower and upper members. The tracks also appear to be within the Douvilleiceras mammilatum Schlotheim ammonite zone of Young, placing the tracks in the middle Lower Albian Stage (~110 mya). Geographic Occurrence (not an all-inclusive list) - North–central and south–central Texas
Remarks For photographs and more information on the Glen Rose Formation trackways: Farlow, J. O. 1981. Estimates of Dinosaur Speeds from a New Trackway Site in Texas. Nature (London) 294, 747–748. Farlow, J. O. 1993. The Dinosaurs of Dinosaur Valley State Park, Somervell County, TX. Austin: Texas Parks and Wildlife Press. Langston, W., Jr. 1974. Nonmammalian Comanchean Tetrapods. Geoscience and Man 8, 77–102. Langston, W., Jr. 1983. "Lower Cretaceous Dinosaur Tracks Near Glen Rose, Texas". In: Perkins, B. F.; Langston, W., Jr., eds. Lower Cretaceous Shallow Marine Environments in the Glen Rose Formation: Dinosaur Tracks and Plants. American Association of Stratigraphic Palynologists Field Trip Guide, 39–61. Lockley, M. 1991. Tracking Dinosaurs. New York: Cambridge University Press. Molnar, R. E.; Farlow, J. O. 1990. "Carnosaur Paleobiology". In: Weishampel, D. B.; Dodson, P.; Osmólska, H., eds. The Dinosauria. Berkeley: University of California Press, p. 224. Shuler, E. W. 1917. Dinosaur Tracks in the Glen Rose Limestone Near Glen Rose, Texas. American Journal of Science 44, 294–298. Spearing, D. 1991. Roadside Geology of Texas. Missoula: Mountain Press, 245–251. Weishampel, D. B. 1990. "Dinosaurian Distribution". In: Weishampel, D. B.; Dodson, P.; Osmólska, H., eds. The Dinosauria. Berkeley: University of California Press, pp. 97–98. Young, K. 1974. Lower Albian and Aptian (Cretaceous) Ammonites of Texas. Geoscience and Man 8, 175–228.
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