At 10:24 a.m. Monday, July 12, in the foothills northeast of Deming, the heavy-duty helicopter gently lowered a sandstone slab onto a flatbed truck on loan from Western Washington University.
A safe distance away in the foothills drizzle, several members of WWU's geology department watched as their prize fossil - a top-grade track of an extinct giant bird - finally reached safety.
When it walked the Earth 50 million years ago, the flightless bird, called Diatryma, stood 7 feet tall and weighed perhaps 350 pounds. Think of a creature the size of basketball star Shaquille O'Neal, but with feathers and a massive beak.
People connected with the discovery and retrieval of the fossil say it's the first undisputed track print of a Diatryma ever found, anywhere.
"I'm really glad this is done," said George Mustoe, a research technician with the department who specializes in paleontology. "It took a long time."
The helicopter was already scheduled Monday to lower logs into the north fork of the Nooksack River to improve salmon habitat, so it was available to carry the 1,300-pound slab from its perch on a rocky ridge down to the truck waiting on a logging road below.
The slab — which measures roughly 37 inches wide, 55 inches long and 10 inches deep, and weighs 1,800 pounds — was driven to WWU, where it will be studied and set up for public viewing.
Keith Kemplin, a Bellingham software writer and a geology hobbyist, found the fossil May 25, 2009, while exploring rocks dislodged by a massive landslide in the Racehorse Creek area.
Kemplin was searching the site with several members of the geology department when he and Mustoe came upon the slab, which was nearly upright in the slide debris. Mustoe was peering at 11 tracks of small birds on the slab when Kemplin saw the distinct, 11-inch by 10-inch three-toed track nearby.
"My role was to say, 'George, look at this,'" Kemplin recalled.
Mustoe took a look.
"I knew right away what it was," Mustoe said.
EARLIER DIATRYMA?
The new track is necessarily being compared to a track found east of Auburn 18 years ago. That's when John Patterson of Maple Valley found a larger, three-toed track in a slab of siltstone that had fallen from a cliff in the Green River gorge.
Researchers disagreed then, and now, whether that track was left by a Diatryma, by another creature, or perhaps by someone playing a hoax.
Martin Lockley, a paleontologist and track expert at the University of Colorado, wrote a report with Patterson endorsing the Green River track as that of a Diatryma or a similar creature. Lockley said the new discovery in Whatcom County will spur added interest in Diatryma and in the Green River fossil.
"I knew all along that the original discovery was authentic," Lockley said. "It doesn't surprise that we have this corroborating evidence. Good for them for finding it."
Mustoe, among others, isn't convinced that Patterson's track belongs to a Diatryma.
"I'm confident it was not a carved hoax," he said. "It may be a track of something, not Diatryma."
Researchers soon will be able to compare the tracks side by side. Patterson's track, which was found on state parks land, is on long-term loan and display at Western.
RIVER TRACKS
The Racehorse Creek track was found in sandstone from the Eocene geologic period, which covers roughly 56 million to 34 million years ago.
The period, which began about 10 million to 15 million years after the demise of dinosaurs, was marked by warm temperatures and the rise of mammals.
The Pacific Northwest was a swampy lowland covered with palms, ferns and vines - similar to what you might find today in Central America or Southeast Asia, Mustoe said.
Residents today are familiar with Chuckanut sandstone. That Eocene material is part of what geologists call the Chuckanut Formation - regional layers of sandstone, siltstone and coal, with numerous outcroppings in Whatcom County, including Chuckanut Mountain and WWU campus.
The sedimentary material was left behind by rivers meandering to the sea from the Rocky Mountains. It would be another 10 million to 15 million years before the Cascade Mountains began to rise skyward.
On their way to the sea, the rivers created sandbars, prime habitat for birds. The fine-grained material was good for displaying bird tracks, but not necessarily for preserving them.
That's one reason few animal bones or tracks from the Eocene period have been found in the Northwest, Mustoe said. The handful of discoveries so far includes a freshwater turtle, a freshwater mussel, and tracks from heron-like and other wading birds, and from tapirs or small horses.
Mustoe said the best track prints occur when the ground is firm enough to support the animal but soft enough on top to capture the track in detail. That's what happened with the latest discovery - the stout sandstone slab is topped by a thin layer of soft silt that later turned to stone.
For a top-quality track to set in stone, Mustoe said, it needs to become firm during a dry spell, then buried softly in sediment before heavy rains or a raging river scours the image away.
With sandstone susceptible to weathering, geologists and fossil hunters are always eager to explore fresh rocks revealed by road construction or by landslides. A massive landslide set the table for the discovery near Racehorse Creek.
SLIP SLIDING AWAY
In January 2009, heavy rains caused flooding and landslides throughout the state. On Jan. 7, perhaps the largest landslide struck Department of Natural Resources land east of Deming.
The massive slide set loose upward of 500,000 cubic meters of debris - more than 20,000 dump-truck loads of rock and timber - from Slide Mountain, with much of it landing 800 feet below in Racehorse Creek. The slide created a massive log jam in the creek, and gouged out a chunk of bedrock, exposing a 75-foot vertical wall.
Kemplin, the geology hobbyist, explored the area that spring and returned soon afterward with Dave Tucker, a research associate at Western's geology department and an expert on the volcanic history of Mount Baker. Soon, Mustoe was exploring the site, too, as were other people.
After they found the Diatryma track, they returned to document and photograph it, and to make a silicon mold.
They knew the slab, if left in place, would eventually crack and erode in the weather. Extracting the Diatryma print from the slab was a no-go, because the siltstone layer on top would crumble. Over time, an informal group came together to preserve the slab, with Tucker taking the lead role.
"We call ourselves the 'Big Bird Committee,'" he said, "or the 'Bird Herd.'"
Besides Tucker, Mustoe and Kemplin, the group included wildlife biologist Susan Madsen, gear-rigger David Sonnen, truck driver Steve James, and outdoor photographer John Scurlock.
Concern about the safety of the slab heightened after someone chipped away two of the small-bird tracks, so the committee and volunteers from Western moved the slab a short distance to hide it, then returned later to conceal it further with rocks.
MUCH TO LEARN
With only a scattering of Diatryma fossils found, and with no other undisputed tracks, the fossil found by Racehorse Creek should be of high interest to paleontologists.
The track shows three prominent, forward-pointing toes, and the presence of a fleshy heel pad, Mustoe said. Skeletons show Diatryma also had a rear toe, but it was too short to reach the ground.
Because flightless birds weigh more than their airborne brethren, a heel pad would provide helpful support for the big bird.
"It tells us a lot about how the Diatryma walked," Mustoe said.
And maybe what it ate.
Early on, researchers believed the bird was carnivorous. Early Diatryma skeletons found in Wyoming were near the bones of small horses, so some people concluded the bird ate horse meat, Mustoe said.
Later, other researchers decided that Diatryma were mostly, if not entirely, vegetarian, because their body makeup suggests they were ponderous creatures rather than speedy predators, and because their beaks were not well-suited for grasping and tearing.
"They were most likely big vegetarians," Mustoe said. "Maybe Diatryma was cracking coconuts with its beak, who knows."
In addition, the three toes in the new track show stubby, triangular toenails, not long sharp talons, another sign the bird wasn't a meat-eater, he said.
Paleontologists also will ponder how the age and location of the new discovery fits what's already known about Diatryma. Fossil skeletons of the birds have been found in the Rocky Mountains area and in New Mexico but not in the Pacific Northwest. And those skeletons are 10 million years older than the new track.
The track found by John Patterson dates to 45 million years ago, about 5 million years earlier than the new one.
"The fact that there could more than one type of bird is likely," Patterson said. "It's a good possibility it's a cousin, separated by 5 million years."
Mustoe, who plans to write a scholarly report about the discovery, said he's undaunted by the scientific debate over Patterson's track.
"I've been through the mill plenty of times," Mustoe said. "It's well within my comfort range."
Author: Dean Kahn | Source: The News Tribune [July 12, 2010]
