Walking with Dinosaurs in Dorset – The Spyway Sauropod Footprints

Summer 2020. The perfect time to head to Dorset to study a dinosaur tracksite that had received little scientific attention since being uncovered in 1997. Or so had been the plan in the preceding months. Despite a certain global hiccup, I was fortunate enough to pick up where I had left off with said plan only one year later than initially intended. In August 2021, I finally travelled to this remarkable site with my field partner in crime and fellow University of Birmingham palaeontology student, Lewis Haller, to investigate how these huge footprints had been made and how the tracksite had changed since its discovery.

January 1997. During routine quarrying of the Purbeck limestone at Keates Quarry in East Dorset, quarrymen Kevin Keates and Trev Haysom discovered several large, shallow, bowl-shaped depressions on a recently cleared surface and recognised them as being dinosaur footprints. As the landowners of the site, the National Trust were notified and subsequently commissioned palaeontologist Joanna Wright to investigate these footprints, 111 of which were soon identified. Given the incredible size of some prints, ranging from 24 up to 130 cm in diameter, and their distinctive shape, the trackmakers were deduced as sauropods. Despite lacking fine morphological detail, the oval tracks represent sauropod pes (hindfoot) prints, while smaller D-shaped tracks represent manus (forefoot) prints.

The mere presence of these footprints was hugely significant. The rock layer in which they were found in the Purbeck Limestone Group was dated to the earliest Cretaceous, around 145 million years ago, when this site was a shelly beach along a coastal lagoon. Body fossils of sauropods from this rock group are incredibly rare, so trace fossils such as footprints offer great value in revealing the presence of sauropods and the environment through which they walked in life. The footprints soon caught the attention of the public and media, featuring in BBC and ITN news reports. After study had concluded, the footprints were covered to protect them while quarrying continued in the surrounding areas. It wasn’t until 2013 that the tracks were uncovered again, this time under the management of the National Trust and Jurassic Coast Trust.

In April 2014, a site survey was conducted at Spyway Quarry using photogrammetry, a technique in which many photographs of an object are taken at multiple angles then compiled in computer software to generate a digital, three-dimensional model. This produced a permanent, virtual record of all the exposed footprints, which can be accessed online at Sketchfab. With the tracks recorded for posterity, the disused quarry was opened to the public in 2016, complete with one information board for visitors to read for context.

August 2021. Lewis and I finally arrived at the site to provide fresh insight into the footprints for our respective dissertations. But what could we do there that had not already been achieved? Our top priority was creating a new photogrammetric model of the tracksite surface to identify how it had changed since the last survey seven years prior. Technology has come a long way since 1997, so subsequent studies using our new photogrammetric model could elucidate new details unseen during previous research. Additionally, new observations could corroborate or challenge previous interpretations. Evaluations of site management and public engagement were also completed to identify strengths and weaknesses that could inform future plans for the site.

So, what did we find? Unsurprisingly, the surface had indeed changed since 2014. The change in colour from pale cream to dark grey was the most obvious alteration, with quarry workers citing this as typical weathering of the Purbeck limestone. What wasn’t so obvious was the change in the number of exposed footprints. 111 tracks were described in the 1998 National Trust report, but we identified an additional 19 tracks during fieldwork and several more from the 2014 photogrammetric model, bringing the total up to 138 footprints. We were unable to find this many in the field for two key reasons. Several footprints had been covered by overgrown foliage or slumped rubble along the surface perimeter, while others had been weathered beyond recognition and could only be confirmed using older records (like the 2014 model or line map from 1998).

The footprints were initially thought to be true tracks, representing impressions in the surface on which the dinosaurs really walked. Our observations, however, indicated that the Spyway footprints were actually transmitted, meaning that the tracks represent layers of sediment deformed underneath the original surface by the sheer weight of these animals. Given the poor track preservation, this is a difficult interpretation to confirm with certainty, but it remains an interesting point to consider while not diminishing the site’s significance.

We investigated visitor engagement with the site using a few proxies. A sensor counter was installed at the main entrance gate to record the number of visitors and time at which they entered the site. The sensor collected data between August 2021 and April 2022, and despite some technical issues during that time, this allowed us to conservatively estimate at least 10,000 visitors to Spyway Quarry annually. A GoPro camera was also mounted on a ledge looking down onto the quarry to take a photo of the surface every 30 seconds during our week of fieldwork. These photos allowed us to track visitor movements across the quarry surface and were used to generate a heat map that visually demonstrates the areas of the quarry that were more frequently visited or where people stayed for longer.

Many visitors showed an interest in what we were doing during fieldwork. We placed a sign by the entrance gate informing visitors of the research we were conducting and welcoming them to chat to us. It was wonderful to see how these footprints sparked such intrigue in people of all ages, which highlights just how important it is for this site to be so openly accessible and enjoyed by anyone. Further insights were gathered by trawling the internet for reviews on the site. Most were positive, noting how special it was to experience the footprints in situ and surrounded by the natural landscape. Others were more critical, citing difficulties in interpreting the footprints, a lack of things to do to maintain interest for longer than 10-15 minutes, and concerns over protecting the tracks.

The final part of my dissertation specifically focused on how to protect the tracksite, a practice that falls under the remit of “geoconservation”. In other countries, such as the USA and Australia, fossil tracksites have had a protective housing or museum built around the footprints, with walkways allowing public access around or over the tracks without direct contact, thereby minimising damage. As the Spyway footprints are in a relatively remote location near the coast and on land owned by the Natural Trust, there exists neither suitable infrastructure nor financing to support such protective measures. Instead, the Jurassic Coast Trust’s “ethos of discovery” allows visitors to interact with the footprints unencumbered at a compromise of accepting that the tracks will degrade over time. So, if you are able to visit these footprints yourself, be sure to take care of the site and its environs.

Spyway Quarry represents the largest in situ easily accessible dinosaur tracksite in the UK, and thanks to research at the University of Birmingham, there are now two open access papers that examine the site in detail:

[1] The condition, use and future of the UK's largest accessible dinosaur tracksite at Spyway Quarry, Dorset (2023).

[2] Sauropod dinosaur tracks from the Purbeck Group (Early Cretaceous) of Spyway Quarry, Dorset, UK (2024).

With thanks to my supervisors Kirsty Edgar and Richard Butler; fellow UoB researchers Lewis Haller, Luke Meade, and Oliver Hill; and our Jurassic Coast Trust co-authors Sam Scriven and Christopher Reedman.