A construction crew discovered the bones of a number of animals, including the femur of an extinct mammoth, while digging near Reser Stadium at Oregon State University.
Loren Davis, an associate professor of anthropology at the university who visited the site, said the bones could be "tens of thousands of years old," The Oregonian/Oregon Live reports. The remains of a bison and a camel were also found in the area, suggesting that the site may have been a watering hole.
"Animals who were sick would often go to a body of water and die there, so it's not unusual to find a group of bones like this," Davis said in a statement from the university. "We had all of these types of animals in the Willamette Valley back then."
Construction work has been halted in the discovery zone as experts explore the area.