Construction crews unearth prehistoric tusk in Ridgefield

Fossil believed to have belonged to mammoth, mastodon

By Marissa Harshman, Columbian health reporter

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The fragments, by all accounts, looked like wood.

When the pieces and surrounding soil were scooped from 30 feet beneath the ground’s surface and dumped into a heap, only one person gave them a second look. To Brad Clark, something about the “wood” just didn’t look right.

And as it turns out, his suspicions were correct. What appeared to be chunks of wood were actually portions of a prehistoric tusk belonging to a mammoth or mastodon.

“It’s kind of mind-blowing, actually,” Clark said. “I was just going off a hunch. … It just didn’t look like a piece of wood to me.”

Clark, a Washington State Department of Transportation inspector, discovered the fragments Jan. 7 at the construction site of the Interstate 5 interchange in Ridgefield. Crews from DBM Contractors of Federal Way were drilling a shaft for the overpass’ foundation on the east side of I-5. When the machinery removed a pile of soil from 30 feet below and dumped it on the ground, Clark noticed the fragments and halted the drilling.

He gathered about half a dozen pieces, ranging from a couple inches to more than a foot long, from the pile of clay and began piecing them together like a jigsaw puzzle. The further he got, the more certain he was the object was not a piece of wood. He began to notice the fibers of the fragments, and, as an avid hunter, compared the texture to that of a ram’s horn. The more pieces he fitted together, the more the object began to look like a tusk or bone. And then there was the stench.

“It did not smell very good,” Clark said. “I couldn’t even put a description on it.”

Clark put the pieces in his pickup and called project engineer Chris Tams and WSDOT’s environmental department to the site. A WSDOT archeologist, Roger Kiers, traveled to Ridgefield from Olympia and monitored the additional drilling at the site. The crews didn’t find any more fragments from the tusk. Still, they were elated with their discovery.

“As soon as it was put back together, you could see the shape,” Tams said. “It was apparent it was definitely some sort of animal remains. It was definitely an amazing find.”

The depth at which the discovery was made, and because the tusk was found beneath the groundwater table, made it impossible to conduct any additional excavation at the site, Kiers said. Construction at the interchange has continued and Tams said the project does not call for any more drilling at that depth.

Kiers took the tusk to the University of Washington’s Burke Museum of Natural History and Culture, where he and a researcher once again pieced the fragments together. When complete, the tusk stretches about 3 feet long and, at the widest part, has a diameter of about 6 inches. The tip of the tusk is about 1 inch around. Mammoth tusks can be 10 to 12 feet long, Kiers said.

The Burke Museum researcher, Bax Barton, suspects the tusk belongs to a Columbian mammoth, which happens to be the official Washington state fossil. Columbian mammoths grazed in the state until about 10,000 years ago. Barton dates the tusk back about 13,000 to 15,000 years, Kiers said. Tests to confirm the type of animal and age of the tusk should be complete in March.

Even though mammoths roamed Southwest Washington, it’s rare to discover tusks and bones, Kiers said. Such discoveries have occurred at various locations in the Puget Sound and Eastern Washington throughout the years, but only a handful of times in this area, Kiers said.

“It would have been a good day for a lottery ticket because the odds of finding it are not so good,” Tams said.

“It’s like looking for a needle in a haystack,” Kiers added.

The tusk fragments were found in a layer of clay flood deposits. In several instances between 13,000 and 17,000 years ago, glacial pieces damming Lake Missoula in present-day Montana broke and sparked flooding of the Columbia River. The river narrowed in the area near Ridgefield and sediments carried from the flood settled there. The mammoth tusk was buried in those deposits.

“We don’t know exactly how this animal got there,” Kiers said. “… It may have just wandered into a pond and got stuck.”

Kiers said he’s unsure where the tusk will go once research and tests are complete but hopes it will be displayed.

Clark is still reeling from the find and trying to convince naysayers that those fragments were more than just chunks of wood.

“I have a bet with the superintendent of the drilling contractor, and he still says it’s a piece of wood,” Clark said. “I just want to make it known that I’m right and he’s wrong.”

Marissa Harshman: 360-735-4546 or marissa.harshman@columbian.com.