Dinosaur Park

College Park Dinosaur Tracks

0 Digs

Theropod dinosaur tracks in the collection of Ray Stanford. Photo by Kathy Addario.

Dinosaur Park is the best place to find Cretaceous dinosaur bones in the Eastern United States, and as it happens the best place to find Cretaceous dinosaur footprints on this side of the Mississippi River is only ten miles away. Avocational fossil hunter Ray Stanford first started finding dinosaur tracks near College Park, Maryland in the early 1990s. With the help of professionals and other amateurs (including Dinosaur Park’s own David Hacker), over 300 specimens have been recovered to date.

The context for these footprints is rather unusual. In other parts of the world, dinosaur tracks are often found in rows or clusters. In those cases, the entire mudflat or stream bed the animal had been walking along was buried rapidly and preserved as a single unit. At the College Park deposits, however, the preserved substrate has been substantially reworked, in both the distant and recent past. Most tracks are found in small loose blocks that have broken out of the outcrop and tumbled into nearby streams. This process makes the tracks relatively easy to collect and transport, but also means that most large tracks are broken and destroyed before they can be found.

Like the quarry at Dinosaur Park, the College Park footprints are preserved in the Patuxant Formation of the Potomac Group. This means that the tracks are roughly the same age as the Dinosaur Park fossils (100-115 million years old), but the two deposits may be separated in time by up to a few million years. Nevertheless, the same sorts of animals are found at both sites, including nodosaurs, medium-sized theropods, giant sauropods, and tiny mammals. It is usually impossible to tell the exact species that left a fossilized footprint, but careful study of the proportions of the foot lets scientists narrow it down to a general group.

Easily the most impressive fossil from the College Park footprint deposits is a body impression of a baby nodosaur. The tiny animal (less than a foot long) is shown lying on its back, with its armored head, ribcage, and right forearm clearly visible. This once-in-a-lifetime fossil was discovered by Ray Stanford and is currently on display at the National Museum of Natural History.