Excavated andIn SituDinosaur Footprints from the Murray Quarry (Early Jurassic East Berlin Formation), Holyoke, Massachusetts, USA

The Murray Quarry was operated during the 1920s and 1930s in sediments of the Early Jurassic East Berlin Formation. I examined 149 footprints of bipedal dinosaurs on three excavated slabs from the Murray Quarry and the in situ track bed. The three slabs I examined are on display at Forest Park, Springfield, MA; the Wistariahurst Museum in Holyoke, MA; and Mount Holyoke College in South Hadley, MA. The footprints belong to three ichnogenera, Eubrontes, Anchisauripus, and Grallator; however, evidence such as length parameters suggests that these ichnogenera might be synonymous. Most of the footprints are referable to Eubrontes and Anchisauripus, which are large- and medium-sized ichnotaxa, respectively. Only two footprints are referable to Grallator, a small ichnotaxon. These ichnotaxa are thought to have been made by theropods, suggesting that there is a preservation bias in favor of carnivores, or that theropods dominated the fauna. The variable morphology of the footprints suggests that they were made over a period of time during which the substrate desiccated. Major results included a high percentage of trotting dinosaurs based on trackway evidence, 43% of the total number of trackways. Additionally, two trackways show evidence for running. There are no preferred trackway orientations.