Documenting Footprints for Tracksites at Dinosaur State Park, Rocky Hill, Connecticut

Tracksites at Dinosaur State Park were first mapped soon after discovery (East Tracksite, ca. 1966) and more than a decade later (West Tracksite, 1980–1981) using near-vertical low-level photographs and hand-traced footprint outlines. Associated photomosaic images/maps on display at the park are thorough but lack topographic detail. We summarize our use of laser scanning, image capture, and digital photogrammetry workflow to map, model, measure, and visualize the East Tracksite (535 m2) and the West Tracksite (335 m2). The East Tracksite, buried since circa 1978, is modeled from 54 historical photographs (ca. 1969) with limited success. Only covering 67% of the tracksite, this model is topographically noisy and is not suitable for detailed topographic measurement due to lower image quality, limited image overlap, and the absence of independent topographic control. In contrast, the West Tracksite models in great detail and includes 751 mostly Eubrontes prints, 89 “swim” traces, other unusual structures, and micro-topographic variations for the three primary host sedimentary layers (lowermost wave-rippled L0, overlain by L1, and wave-rippled L2). Traces are most numerous on L1 (approximately 50% of Eubrontes, nearly all “swim” prints, and one of two varieties of enigmatic structures). Unidentified structures include double-imprinted 0.5–1.5 m–long curved and segmented grooves on L0, and an approximately 2.3 m–long series of alternating oval impressions on L1. Trackways with six or more prints reveal several groups with similar but widely distributed orientations. Footprints within individual trackways are deeper, larger, and more voluminous on L0 than on L1 and/or L2, which may imply more easily deformed L0 sediments, although L1 and/or L2 tracks often are partially sediment-filled thereby diminishing track depths and volumes.