For two decades, students walked past an unassuming beige rock on their way to and from class—and occasionally stuck wads of used chewing gum on it. Now, paleontologists have discovered the slab is covered in 200-million-year-old dinosaur tracks,

A slab of rock at an Australian high school, a boulder in a parking lot, and a bookend in a private collection feature 200-million-year-old dinosaur footprints.

A palaeontologist’s call-out for rocks bearing dinosaur footprints around an Australian town has borne fruit, including a densely packed set of prints sitting in the foyer of the local high school, unbeknown to many students.