Maintaining the Past: Road Crews and Fossils at Colorado National Monument

By Austin Shaffer, paleontology intern, Colorado National Monument.

Recovering a block with turtle tracks (Chelonipus) with the Museum of Western Colorado, September 2010. NPS photo.

Rim Rock Drive, the historic scenic road through Colorado National Monument, looks over the Grand Valley and through the monument's spectacular geology — rock units up to about 1.7 billion years old, many of them full of fossils, such as the rich Morrison Formation of the Late Jurassic. Where the road cuts these layers, rock often breaks loose and falls into the road and its ditches, so the park's Facilities staff maintain it constantly — which makes meeting fossils very likely. The monument's Maintenance, Trails and Masonry crews have handled those encounters in a way that has avoided needless damage and saved important specimens.

Facilities staff clear sediment from behind a fossil-bearing block to move it clear of ditch work, June 2023. NPS photo.

Two decades of finds

Staff have come and gone, but the crews have protected the park's fossils for decades; the 2010s give the best examples.

Sauropod tracks as parking barriers. In the late 1990s or early 2000s, several large sandstone blocks carrying sauropod track casts, from the lower Morrison Formation, were placed along Rim Rock Drive — to stop roadside parking, before anyone knew what they were. Dr. Kelli C. Trujillo documented them in 2004 and advised checking the site regularly against vandalism. After a 2015 assessment the park decided to move them. A first try in November 2015 failed — the blocks were too heavy — but a second, a few weeks later, got them to a maintenance yard. They now sit at the park's Resources office, and the park plans to use them in its interpretive programmes.

The first, failed attempt to move the sauropod track blocks, November 2015; the right-hand picture shows a hand-and-foot pair. NPS photo.

A rare turtle trackway. Nearby, another lower-Morrison site holds track casts of an ornithopod dinosaur (Dinehichnus socialis) and a turtle (Chelonipus). Marilyn Sokolosky of Fruita, Colorado, reported it in 2005, and paleontologists Martin Lockley and John Foster published it in 2006. When a block of turtle tracks fell a few winters later, Museum of Western Colorado and park Facilities staff recovered it together. It was unveiled at the monument's visitor center on the first National Fossil Day, in October 2010, and went on to the museum's Dinosaur Journey, where thousands see it every year. It is one of only three specimens of its kind known from the Morrison Formation.

The turtle track slab on show at the Museum of Western Colorado's Dinosaur Journey, August 2023. NPS photo.

A trail worker's eye. In 2010, trails worker Jim Robertson, working along the road, found a loose three-toed track cast on a Morrison slope, worked around it and reported it at once. Visiting with park staff, John Foster, then the museum's curator, found more: possible crocodyliform swim traces and a slab of what may be lizard tracks — possibly among the only such traces known from the Morrison. Both the "lizard" slab and the three-toed track were collected, and both still need further scientific study.

Summer 2023

During a 2023 paleontological inventory of the monument, the author found fossils in rockfall along the road — loose sauropod track casts, petrified wood and a large block with dinosaur bone — just as road crews planned to break up the fallen rock. Maintenance worker Jay Iadonisi and the author drove the road and flagged every roadside fossil. Plans for each one were made with the park's chief of resources, Jessica Resnik, NPS senior paleontologist Vincent Santucci and NPS paleontology consultant Justin Tweet, and Facilities staff carried them out: recovering, relocating or repositioning each fossil.

Then, while breaking up a large block of lower-Morrison rockfall, the crew flipped it and found a large three-toed track on its underside. They recognised it, left the block alone and called Resources staff, then moved it to a maintenance yard. This theropod track may be among the largest three-toed footprints known from the Jurassic of western Colorado.

A large three-toed theropod track found by Facilities staff during ditch maintenance, June 2023. NPS photo.

Why it matters

Over two decades, the monument's Facilities staff have discovered, relocated and recovered fossils across the park. Several finds have proved scientifically promising, and some are now on public display. Protecting fossils in the National Park Service depends on divisions working together — and at Colorado National Monument the road crews are a large part of it.

Sources

• National Park Service, "Maintaining the Past: The Role of Facilities Staff in Paleontological Resource Management at Colorado National Monument," by Austin Shaffer. https://www.nps.gov/articles/000/maintaining-the-past-the-role-of-facilities-staff-in-paleontological-resource-management-at-colorado-national-monument.htm
• Rewritten in hubnx's own words.