Distribution and Significance of Mesozoic Vertebrate Trace Fossils in Dinosaur National Monument

Dinosaur National Monument (DNM) encompasses a large area with surface exposures of Mesozoic rocks. Although only one isolated footprint (from an unknown locality) had previously been discovered at DNM, there is a high potential for preservation of fossil footprints in this area, as has been proven by discoveries in similar rocks in the region around DNM, and during research activity at DNM. As reported by Lockley et al. (1990), the purpose of this research is to seek, document and interpret vertebrate trace fossils in any of the ten potentially track-bearing Mesozoic stratigraphic units in which footprints might be discovered. During the course of the first year (6/90-6/91) the University of Colorado at Denver Research Group documented 11 localities where tracks were discovered at one or more stratigraphic levels (Lockley et al. 1990, 1991). In the first part of the second year of investigation (7/91-1 0/91) the research group discovered an additional five localities, and three additional sites were reported to us by Park Paleontologists and other researchers. This brings the total to 19 localities, of which three include at least two levels with tracks (Total = 22 localities). As discussed below, the tracks provide evidence of the activities of several dozen animals that represent distinct ancient animal communities