PORTLAND, Ore. (AP) — University of Oregon scientists discovered a dinosaur bone, the first fossil from a land-dwelling prehistoric creature found in the state.

The Oregonian/OregonLive reported the discovery came in 2015 when earth sciences professor Greg Retallack was in central Oregon, leading a field expedition of students looking for fossilized plants near the town of Mitchell.

The group came upon a pile of ammonites, spiral shaped sea creatures that went extinct around the same time as the dinosaurs.

Retallack's revelation was first revealed in a paper published this month in the Journal of Vertebrate Paleontology.

The fossil, a toe bone, is thought to be about 103 million years old, dating back to the Cretaceous period. It belonged to a creature called an ornithopod, a 17-foot (just more than 5 meters) long herbivore that weighed up to 1,500 pounds (680 kilograms) and walked on two legs.