Dinosaur tracks research for Dinosaur State Park, Rocky Hill, Connecticut

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

New papers:

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Michael P. Ross, Chelsey F. Knyff, Patrick W. Murphy, Emily M.I. Rochette, Rachel C. Burns
History of Dinosaur State Park, Registered National Natural Landmark, One of North America's Largest in Situ Dinosaur Trackways, Rocky Hill, Connecticut
Bulletin of the Peabody Museum of Natural History 66(1): 51-69
doi: https://doi.org/10.3374/014.066.0103
https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-66/issue-1/014.066.0103/History-of-Dinosaur-State-Park-Registered-National-Natural-Landmark-One/10.3374/014.066.0103.short

Although dinosaur tracks have been found in the Connecticut River valley for well over 100 years, the tracks found in 1966 in Rocky Hill, Connecticut, were something unique and special. Through the efforts of various university faculty, students, community leaders, and state officials, this location—that contains over 1,800 identified early Jurassic dinosaur tracks—was declared a state park in less than 1 month from the discovery of the tracks and made a Registered National Natural Landmark in 1968. The history of the park is complicated, yet the vision was simple: preserve the tracks and trackway in situ and develop a world class educational institution with one-of-a-kind access to a dinosaur trackway only 2 minutes away from an interstate highway and major national transportation thoroughfare. Although funding, staffing, and public awareness challenges have ebbed and flowed, Dinosaur State Park is still the unique and hidden gem that it was from its inception. The vision of the original planners from 1966 is still the vision for the current park almost 60 years later, even though future expansion is unclear due to limited state resources. This paper is written from the perspective of the state of Connecticut focusing on the political, educational, and community efforts to preserve and expand the park.

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Daniel L. Brinkman & James A. Hyatt (2025)
Archival Evidence of Strong, Longtime Ties between Yale Peabody Museum's Division of Vertebrate Paleontology and Connecticut's Dinosaur State Park
Bulletin of the Peabody Museum of Natural History 66(1): 71-86
doi: https://doi.org/10.3374/014.066.0104
https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-66/issue-1/014.066.0104/Archival-Evidence-of-Strong-Longtime-Ties-between-Yale-Peabody-Museums/10.3374/014.066.0104.short

Documents in the Division of Vertebrate Paleontology Archives at the Yale Peabody Museum demonstrate deep ties between the division and Dinosaur State Park. These ties began on 25 August 1966 and have continued intermittently to the present. A number of people associated with the division played pivotal roles in the establishment and development of the park and in the nurturing and fulfillment of its educational and scientific missions. They did so by either contributing to the excavation of the tracksites, supporting the park's educational programs, seeking recognition of the park's importance from both the Society of Vertebrate Paleontology and National Park Service, writing about the site, and/or documenting and analyzing the over 1,800 archosaur footprints found there. Most notable has been the work of John Ostrom, Grant Meyer, and Peter Galton. It is hoped that the longtime ties between the division and the park will only strengthen in the years ahead.

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James O. Farlow, Daniel L. Brinkman & James A. Hyatt (2025)
The Yale Peabody Museum Dinosaur Footprint Block/Slab from Dinosaur State Park, Rocky Hill, Connecticut
Bulletin of the Peabody Museum of Natural History 66(1): 87-97
doi: https://doi.org/10.3374/014.066.0105
https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-66/issue-1/014.066.0105/The-Yale-Peabody-Museum-Dinosaur-Footprint-Block-Slab-from-Dinosaur/10.3374/014.066.0105.short

In 2019, West Haven High School in Connecticut donated a large block or slab of rock containing five or six dinosaur footprints to the Yale Peabody Museum. The slab was one of many uncovered in 1966 and 1967 during the exposure of dinosaur tracks at a site in Rocky Hill that became Dinosaur State Park. The footprints are preserved as natural casts on the underside of the arkosic sandstone that formed from sediment that filled in the footprints and covered the actual tracklayer. Preservation of the footprints varies, but one of them is well enough preserved to be assigned to the theropod dinosaur ichnogenus Eubrontes, a second is very likely Eubrontes as well, and a third, smaller, faintly impressed footprint may be Anchisauripus. No two footprints can be assigned to the same trackway, and the prints show different orientations, indicating that they were made by different animals. Thus, some of the natural casts of footprints in the undersurface of tracksite-covering slabs at Dinosaur State Park have the potential to yield ichnotaxonomic information, even if the natural casts can no longer be matched up with the actual tracks of which they are topographically negative copies.
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James A. Hyatt, James O. Farlow, Peter M. Galton & Patrick R. Getty (2025)
Documenting Footprints for Tracksites at Dinosaur State Park, Rocky Hill, Connecticut
Bulletin of the Peabody Museum of Natural History 66(1): 99-139
doi:  https://doi.org/10.3374/014.066.0106
https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-66/issue-1/014.066.0106/Documenting-Footprints-for-Tracksites-at-Dinosaur-State-Park-Rocky-Hill/10.3374/014.066.0106.short


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.

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Peter A. Drzewiecki & James A. Hyatt (2025)
Distinguishing True Tracks from Undertracks and Overtracks at Dinosaur State Park, Rocky Hill, Connecticut
Bulletin of the Peabody Museum of Natural History 66(1): 141-174
doi: https://doi.org/10.3374/014.066.0107
https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-66/issue-1/014.066.0107/Distinguishing-True-Tracks-from-Undertracks-and-Overtracks-at-Dinosaur-State/10.3374/014.066.0107.short


About 750 Eubrontes footprints occur on three stratigraphic layers in the Jurassic East Berlin Formation at Dinosaur State Park in Rocky Hill, Connecticut (USA). Several trackways and individual tracks are preserved on multiple sedimentary layers, as true tracks on one layer and as their corresponding transmitted undertracks or overtracks on another, making the park an ideal place for investigating morphological, stratigraphic, and sedimentological criteria for distinguishing true tracks from undertracks and overtracks. True tracks are deeper and preserve more anatomical detail than corresponding undertracks and overtracks. Sedimentary features associated with tracks, such as skin impressions, displacement rims, radial fractures, and structural deformation features, typically form on the tracked surface but may be transmitted to layers below. Of these features, only displacement rims occur at Dinosaur State Park, but even they are uncommon. The relationship between the footprint and sedimentary structures is used to determine the relative timing of track registration. Wave ripples on tracked surfaces predate the tracks and are destroyed by the trackmakers, but ripples are preserved in overtracks and some undertracks. Microbial mat formation enhanced preservation of tracks by binding sediment, decreasing the sediment plasticity, and minimizing erosion after track registration. Internal laminae in beds at Dinosaur State Park can reliably identify the tracked surface. Beds below the tracked surface preserve deformation associated with vertical compression when the track was registered. Beds overlying the tracked surface preserve distinct lateral and vertical sediment fill patterns. These criteria are used to assign tracks to a specific tracked surface to identify which dinosaur footprints were registered roughly contemporaneously. This is critical for understanding paleoecology, investigating possible gregarious behavior of trackmakers, determining the type of locomotion (walking, running, or swimming), and exploring other trackmaker behavior in their environment. Observations from Dinosaur State Park can be applied to other tetrapod tracksites.

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James O. Farlow, Peter M. Galton, James A. Hyatt, Peter A. Drzewiecki, Amanda Penrod & James Whitcraft (2025)
Dinosaur Footprints from the Lower Jurassic East Berlin Formation, Dinosaur State Park, Rocky Hill, Connecticut
Bulletin of the Peabody Museum of Natural History 66(1): 175-259
doi: https://doi.org/10.3374/014.066.0108
https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-66/issue-1/014.066.0108/Dinosaur-Footprints-from-the-Lower-Jurassic-East-Berlin-Formation-Dinosaur/10.3374/014.066.0108.short

In 1966 and 1967 three-toed footprints made by bipedal dinosaurs were discovered in the Lower Jurassic East Berlin Formation at Rocky Hill, Connecticut [now Dinosaur State Park (DSP)]. The tracks occur in a larger East Tracksite and an adjacent smaller West Tracksite. We present a thorough description of the dinosaur tracks of the West Tracksite, and as complete a description of the East Tracksite as is presently possible. Footprints mainly occur in two beds; tracks in the lowermost of these beds are mostly or entirely transmitted undertracks. Most DSP trackways were made by dinosaurs walking normally. Quality of morphological preservation is variable. Prints show features consistent with those of tracks attributed to theropod dinosaurs, being longer than broad, with acuminate toetips, sometimes with a slight sigmoid curvature to the digit III impression. Two discrete digital pads are sometimes seen in the digit II impression. Most of the footprints fall in the length range of 30–40 cm, but some prints in the East Tracksite were made by considerably smaller dinosaurs. The more common larger prints are consistent with the ichnotaxa Eubrontes and possibly Kayentapus, and the smaller prints with Anchisauripus (or Grallator). Trackways are mostly linear, with relative stride lengths comparable to those of other trackways attributed to theropods; footprints generally angle outward with respect to the trackmaker's direction of travel. Some trackways, however, show more erratic movements, and one trackway preserves touchdowns of the manus. Although some trackways parallel others, for the site as a whole there is no clearly defined direction of trackmaker travel. Some unusual trackways show features that in other ichnofaunas are interpreted as showing swimming or punting behavior on the part of their makers, but making the same inference for the odd DSP trackways is complicated by the possibility that the putative “swimmer” footprints are undertracks.

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[Gregory Paul]

The full size Richard Rush Studios Dilophosaurus that I designed and Roger Walsh beautifully constructed with the help of Bon Baird is on display at the park museum. 

GSPaul