Where to See Ancient Plants and Animals
Unlike some of its neighboring western states, Washington isn’t known for its fossil finds. But discoveries of prehistoric animals and plants are being made all the time. Learn where to hunt for and see the Evergreen State’s fascinating fossils.
In January 2009, a massive landslide occurred in the foothills of Washington’s Mount Baker. Debris tumbled 800 feet down the south valley wall of Racehorse Creek, a tributary of the North Fork Nooksack River, churning up bedrock in an area rich with fossils.
Among the remnants of ancient palm fronds and other prehistoric leaf imprints, a team from Western Washington University discovered an incredible new find: the fossilized tracks of a giant and flightless bird known as Diatryma. They were the first footprints ever recorded of this 7-foot-tall, 330-plus-pound giant-headed creature, which wandered the Pacific Northwest 50 million years ago.
“We flew out one of the best tracks via helicopter and have it on display at Western Washington University’s geology museum,” says George Mustoe, a retired WWU paleontologist and current research associate, who was one of the discoverers of the tracks. It was a huge find, not only for its rarity, but also because fossils in Washington are an anomaly within themselves.
Diatryma footprint by George Mustoe
Although western states like California, Montana and Wyoming have unearthed relics ranging from the bones of a hadrosaurs to the pelvic bloc of a T-Rex, “It can be difficult to find fossils in Washington,” says Elizabeth A. Nesbitt, curator emerita at Seattle’s Burke Museum of Natural History and Culture. “This is because we have so many volcanoes that have covered both the eastern and western sides of the states, and all the plate tectonics have squished everything up.”
Washington’s first ever dinosaur bone wasn’t even discovered until 2015, and this fragmented femur piece from a theropod (though the exact genus of which is unknown), found on Sucia Island, remains the only one to this day. It’s on display at the Burke Museum.
There’s also the fact that much of the land surrounding Washington’s beaches and rivers is private property, restricting public access to places where fossils are likely to exist. But although there may be limited places to hunt for fossils of your own, there are plenty of places to see Washington fossils — if you know where to look.
“Washington is an area that’s a boundary between the tropical California,” says Nesbitt, “and the very cold Alaska. It’s the intersection of these very two different floras and faunas and it has really unique stuff. Most of Oregon and Washington is considered one paleontological unit, though once you get into British Columbia things start to change.”
According to Mustoe, the bedrock of almost the entire state is made up of exotic terranes, or pieces of island chains and microcontinents that have merged with the edge of North America, welding together ribbons of different geological histories.
For example, although Bonnie Lake Island in eastern Washington is home to billion-year-old Precambrian schist, the state’s northern Olympic Peninsula sports loads of much younger marine fossils — including an array of fossils conveying the early evolution of whales, which began about 35 million years ago. “Only places like New Zealand and Japan have something similar,” says Nesbitt.
Washington has produced numerous fossils from mammoths and mastodons. Both were large elephant-like creatures that existed during the last Ice Age. In fact, the Columbian mammoth — known for its towering height and curved tusks — is the official state fossil. Other Ice Age fossils that have been discovered in Washington include the bones of giant bison, as well as one the state’s most legendary fossil finds: the remnants of a roughly 12,700-year-old giant ground sloth buried beneath Seattle-Tacoma International Airport.
Construction workers unearthed more than half of the extinct mammal’s remains while digging near one of the airport’s runways. Again, the Burke Museum has a complete reconstruction of its skeleton on display.
Along with an abundance of marine and Ice Age fossils, Washington is known for its spectacular leaf fossils, as well as petrified wood (Washington’s state gem). Fossilized tree ferns and palm fronds exist around coastal spots like Seattle and Bellingham, while there’s an extensive collection of fossil wood around the Columbia River and up to Spokane.
There are other Washington fossil finds similar to Sea-Tac’s giant ground sloth that are well-worth a standalone mention.
Manis Mastodon Site
In 1977, a farmer digging on his Olympic Peninsula property in Sequim happened upon the tusks of an American Mastodon, leading to a much larger archaeological discovery. Along with the remains of bison, caribou and plant macrofossils, the site contained the bones of the mastodon itself.
One excavated, they became one of the state’s most publicized fossil finds. That’s because one of the mastodon’s rib bones had what looked to be a spear embedded in it. In 2011, scientists used CT scans to prove that this was indeed a human spear, hand-crafted from another mastodon’s bones — evidence that people had been hunting these magnificent creatures up to 14,000 years earlier.
While the 2-acre archaeological site is listed on the National Register of Historic Places, the mastodon’s fossilized remains are on display at the Sequim Museum & Arts, in downtown Sequim.
Blue Lake Rhino Cave
About 15 million years ago, a volcano erupted in what’s now northeastern Washington, trapping an ancestor of a modern rhino in lava near present day Coulee City. Most of the animal’s bones had disintegrated or fallen from the place over time, leaving a cast of the rhino’s body behind. It wasn’t until the 1930s that two Washington couples happened upon the prehistoric mold, reporting it to scientists who then made a cast of the cave’s interior. While the cave remains publicly accessible, it’s not easily reachable or entirely safe. For the best view, visit the Burke Museum, which has an exact replica of the cave — complete with the rhino’s upside-down imprint.
Depiction of a Diatryma by Marlin Peterson
Museums and Fossil Sites
Seattle’s Burke Museum is the premier place to view fossils in Washington. Not only is it home to the state’s first and only dinosaur bone (“It’s small, says Nesbitt, “but it’s ours”) — but the museum also features such unique displays as the remains of a Columbian mammoth excavated from eastern Washington’s Tri-Cities Area.
“The bones are so fragile that they sat in storage for a long time,” says Nesbitt. “That is, until the museum figured out a way to create 3D printed replicas from other mammoth bones in the Burke’s collection and combine them to make a full-scale skeleton.”
Along with three fossils of ancient whales, the Burke also boasts a real rarity: a fully intact T-Rex skull, one of only 15 or so found on the planet. Though the skull was excavated in Montana, Burke volunteers were the ones who discovered it.
One of the museum’s true hidden gems is a magnificent wall of ammonites: extinct marine mollusks known for their ribbed spiral shells that lived more than 66 million years ago. “There’s a small section of ammonites from Washington state,” says Nesbitt, “and the others are from all over the world.”
Stonerose Interpretive Center
Located in the town of Republic in northeast Washington, Stonerose features fossils dating back 49 million years. “This is the one place where we continuously send people,” says Nesbitt. “Stonerose is amazing!”
“You go to their museum, pay a fee (typically $15 per person), and pick up a collection permit,” says Muscoe. “You’re then allowed to keep three fossils a day, and the other finds get turned over to the center.”
Fossils found onsite have included fish, leaves and even bird feathers.
Other Fossil Areas
The 7,124-acre Ginkgo Petrified Forest State Park is tucked within Wanapum Recreation Area along the Columbia River. It is known for its rare specimens of fossilized Ginkgo trees, as well as an interpretive center that’s home to one of the most diverse petrified wood collections in North America. Everything from fossilized sweetgum to Douglas fir has been unearthed here. Another option is a visit to the Saddle Mountains in south-central Washington, where recreational collecting of fossilized wood is allowed on public lands.
There’s also The REACH Museum in Richland where a small display of plant fossils highlights the Hanford Reach area of the Columbia River. Remnants include a fossilized cypress leaf, a fossil pine cone and petrified wood such as an elm specimen from nearby Vantage.
“In Oregon, the John Day Fossil Beds are fun,” says Nesbitt. This U.S. national monument tells the story of both plant and animal evolution through everything from haplohippus (three-toed, leaf-eating horses) fossils to pressed remnants of ancient fish, leaves and amphibians.
–Written by Laura Kiniry
–Top Photo by Andrea Godinez/Burke Museum
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