The 10,000-year-old bones of a mammoth and other extinct ice age mammals have been unearthed in the north end zone of Oregon State University's Reser Stadium.

Construction crews digging up earth during the Valley Football Center expansion project uncovered a large femur bone from a mammoth as well as bones from a bison and a camel, OSU spokesman Steve Clark told The Oregonian/OregonLive.

"Our archaeologist believes this could have been the location of a pond, a watering hole for these animals," Clark said, "or a place where they came to die."

Construction crews called Loren Davis, an associate professor of anthropology at OSU, to the site after the initial discovery.

"There are quite a few bones, and dozens of pieces," Davis said, adding that no human bones were discovered. "Some of the bones are not in very good shape, but some are actually quite well preserved."

Davis said the discovery of the ancient mammal bones is not unusual in the Willamette Valley, where mammoths once roamed by the thousands.

Long before regular traffic jams, a sprawling Fred Meyer and a Cabela's outdoor-gear emporium dominated the landscape, Tualatin's Southwest Nyberg Street, for example, was part of a prehistoric ice age trail for giant tusked mastadons.

"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 said in a statement issued by OSU. "We had all of these types of animals in the Willamette Valley back then."

Davis said mammoths went extinct 10,000 years ago. The bones, he said, could be "tens of thousands of years old."

Mammoth bones discovered at Oregon State University 15 Gallery: Mammoth bones discovered at Oregon State University

Crews began digging up the north end of Reser Stadium after the Beavers' season ended for the football center expansion. A worker digging at a depth of about 10 feet made the initial discovery of the femur bone and the contractor immediately stopped work in the area, Clark said.

Work has been suspended in the pit, with crews moving to other areas of the construction zone while Davis and other experts examine the find.

Since the discovery does not include humans or ancient artifacts, it is not considered a protected archaeological site, university officials said. Oregon has no special regulations governing the preservation of paleontology finds.

"Nonetheless, we can learn a great deal about what the ancient environment of the Willamette Valley was like from this discovery," Davis said.

Davis said he and his students will excavate a large pile of dirt from the site to see if they can find other bones.

"It just goes to show there's a whole world of the past that exists underground," Davis said. "It's so neat we could find it here at Reser Stadium. As you're watching a football game, you can think, beneath your feet, lie the bodies of extinct animals that relate to the past."

-- Joseph Rose

503-221-8029

jrose@oregonian.com

@josephjrose