Ancient Residents Left Their Mark in History

At the ragged edge of the Ice Age, after glaciers had begun releasing their grip from the landscape, the Willamette Valley was a land of giants.

Bison 8 feet tall at the shoulder roamed the valley, as did sloths weighing 9,000 pounds. American lions that resembled their African counterparts, but were bigger, prowled the brushy savanna and peat bogs that made up the valley. There were saber-tooth tigers and raptors with 14-foot wingspans.

That was 12,000 years ago. Now, bits at a time, remnants of the long-extinct wildlife are being excavated from a drainage area near Woodburn’s Legion Park.

More than 200 bones or bone fragments have been found at the dig.

Seven strands of human hair have also been discovered.

One of the strands was carbon-dated at 12,050 years old. Other hairs will be tested at labs in Portland and Tennessee for age and DNA to indicate just who the early inhabitants of the valley were.

“Hints of stone and bone tools” were also found, said Alison Stenger, of the nonprofit Institute of Archaeological Studies, which is conducting the investigation with the Condon Museum at the University of Oregon and the city of Woodburn.

There are indications that humans may have chopped off chunks of beasts that perished at the site.

“There are suspicious-looking marks on a femur and on a couple of foot bones, and a couple of toes. The toes with cut marks on them are three inches wide, and about three inches long,” Stenger said.

“We put a microscope on these to determine whether the marks are from animal predation or cut marks from a human, and they look like cutting marks.”

On a recent day at the dig, Chuck Hibbs, an archeologist and co-director of the project, showed a plastic bag containing a bone fragment--a piece of mastodon femur.

The bone in the bag had a fracture, which could have been created by some other animal or by humans looking for marrow, Hibbs said.

Hibbs said dig workers are finding bones with spiral fractures, indicating that the bone was fresh when it was broken.

“Dry bones tend to break at right angles,” he said.

There is no reason why there shouldn’t have been humans in the region after the Missoula Flood wiped the valley clean of life somewhere around 12,000 years ago, Stenger said.

The flood was the result of a breakout of a huge reservoir of water released when an ice lobe gave way near present-day Lewiston, Idaho.

The resulting wall of water has been calculated at 1,000 feet high at the Dalles. It left the Willamette Valley under hundreds of feet of water in a lake that stretched as far south as Eugene.

Hibbs called it “one of the greatest catastrophic events of all time.”

A layer of gray silt that has been traced to eastern Washington was left by the receding flood waters. The bones and other items found at Legion Park postdate the flood.

Hibbs says that after flood waters receded, the valley was dotted with a series of lakes, bogs and ridges, and soil under the lakes was a mixture of peat and soft sand that apparently trapped and drowned animals who wandered or were chased into it.

About 6,800 years ago, a clay cap formed over the bogs, sealing them from the decaying effects of oxygen and helping preserve the bones, which are now partially mineralized.

The concentration of remains at Legion Park has just recently come to light. At a nearby school, however, city workers digging a ditch in 1988 began finding large quantities of bone, Hibbs said.

“It was rumored they took pickup-loads of them home,” he said.

Everything found at the site now by law belongs to the state or to Woodburn, which is considering a museum, Hibbs added.

Farmers have been finding bones from mastodons, bison and sloths in the Willamette Valley for years.

“But this is the first large-scale investigation,” Hibbs said.