No Stone Unturned

Archaeologists on the trail of earliest Americans at Cooper’s Ferry
Students conducting excavation at Cooper's Ferry Archaeological Field School. (Photo: Loren Davis)

(Above) Students excavate a pit at Cooper’s Ferry Archaeological Field School in 2013. (Below) In 2013, Loren Davis and his team found these stemmed projectile points in a single pit at the bottom of the Cooper’s Ferry site. (Photos: Loren Davis)

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It may have been late afternoon after the sun had set below the canyon rim on a cloudless summer day. Or early morning, as dew still clung to grasses by the fast-flowing stream. At this place along the lower Salmon River thousands of years ago, someone laid four stone projectile points side by side in a shallow pit. It’s likely that bones, stone tools and what archaeologists call “debitage” (stone chips and flakes) had been tossed in earlier. With hands probably calloused from a lifetime of pounding, carving and cutting with rock, this person covered the pit and topped it with round cobblestones to mark the spot.

We’ll never know who left those precious points. Was it a man or a woman? An artisan skilled in making razor-sharp blades from local rocks? Maybe a young hunter who was heading up the canyon in search of deer to feed his family.

It’s a good bet that someone planned to return and retrieve them. These people, whose ancestors may have migrated from Asia at the edge of an ice sheet or along a coastal waterway, needed such weapons to survive. Points made from local rocks —obsidian, chert, basalt — comprise the business end of darts most likely thrown with a device known as an “atlatl” (similar to the ball-throwing sticks some people use to exercise their dogs). But these four points, the result of hours of meticulous flaking and retouching, remained underground. Dust from the nearby plateau blew year by year through the steep-sided canyon and buried them ever deeper. Archaeologists think they remained there for more than 13,000 years until a graduate student dug them up in 1997. He found them at the bottom of a pit nearly 10 feet below the surface.

That student was Loren Davis, now an associate professor of anthropology at Oregon State University. With OSU students and other researchers, he has embarked on a journey to learn more about the people who made those artifacts.

In Idaho's lower Salmon River canyon, the Cooper's Ferry archaeological site is adding important findings on prehistoric inhabitants. (Photo: Hayden Wilcox)

In Idaho’s lower Salmon River canyon, the Cooper’s Ferry archaeological site is adding important findings on prehistoric inhabitants. (Photo: Hayden Wilcox)

Davis knows the trail is cold. “Archaeology is a gamble. You never know what’s going to work out,” he says. During his graduate school years he had considered working at prehistoric sites in Siberia and Baja California, Mexico. But for this Oregon native, the West held the strongest attraction. Five years into an ambitious exploration of a riverbank just above the lower Salmon, his roll of the dice is paying off. His team has already found the oldest examples of a type of stone tool that is unique to the Far West. And ancient artifacts continue to accumulate with each summer field season.

Ice-Age Hunters

In 1997, Davis was no stranger to the lower Salmon River canyon. As a master’s student at Oregon State, before finding the points, he had worked as an archaeologist for the Bureau of Land Management, reviewing and inspecting cultural sites along the river. Later, while pursuing his Ph.D. at the University of Alberta, he combined archaeology with geology, particularly the last 2.5 million years, a period known as the Quaternary. It was an epoch of ice-age cycles. Now-extinct species of camels, horses, wooly mammoth, mastodon and bison roamed the steppes across Europe, Asia and North America. Whoever left those points along the lower Salmon probably hunted them.

That environment holds a key to the human story in North America, Davis says. “The world was so dramatically different at that time. There were ice sheets and giant lakes, and sea level was much lower. You have to have a geological outlook to make sense of a lot of it.”

Now, every summer, he heads back to the lower Salmon, to its confluence with Graves Creek at a spot known as Cooper’s Ferry, just south of the farm and ranch community of Cottonwood. Since 2009, he has led the Cooper’s Ferry Archaeology Field School (see “Searching the Past”), where students from Oregon State and around the country learn to scrape and sift millimeter by millimeter through soil as they look for clues left by those ice-age hunters.

So far, working under the shade of a mesh tarp in temperatures often over 100 degrees, they have found, photographed, labeled and bagged more than 30,000 objects: stone tools, tool-making flakes, mussel shells, animal bones (fish, rodent, rabbit, deer) and projectile points.

Loren Davis holds the largest of 13 stemmed points found in a pit at Cooper's Ferry in 2012. (Photo: Alex Myers)

Loren Davis holds the largest of 13 stemmed points found in a pit at Cooper’s Ferry in 2012. (Photo: Alex Nyers)

In 2013, they discovered part of a wolverine skeleton buried in a pit with a stemmed dart point and, in another nearby pit, 13 other points lying next to each other. They have found soil burned red, heat-cracked rocks and charcoal from ancient cooking fires. Davis estimates they are about halfway through an excavation that will take the better part of 10 years.

“This is a huge responsibility,” says Davis. “If you’re going to open up a site that’s this special, you have to be willing to do it at a very careful, slow pace. So in most years, we move downward only 40 to 50 centimeters (15 to 19 inches). We’re trying to find everything the size of a dime or larger in place. We want to uncover it in the ground and record it.

“The goal is not just to find stuff. If that was it, we’d just get a front-end loader, dig it all out and screen it. But we wouldn’t know how the artifacts go with each other, how the dates match with them and so on.”

Clovis and More

It’s the extraordinary care with which the work is being done, as well as the quality and the age of the artifacts, that make Cooper’s Ferry a prime site for archaeologists. The results are adding new perspectives to discoveries made at other Pleistocene-age landmarks in the West. Organic remains at those sites — the famous sagebrush bark sandals recovered by Luther Cressman at Fort Rock Cave; animal bones, fabric and human wastes (known as coprolites) found by Dennis Jenkins at Paisley Caves — have shed light on how early people lived.

For much of the 20th century, the story of the earliest people in North America was known as “Clovis First.” It proposes that all Native Americans descended from a single cultural group. In the 1930s, artifacts found near the New Mexico town of Clovis spurred a search for more such objects. Clovis culture became associated with a stone point that is fluted on both sides, meaning it features a concave channel running from the base toward the tip. Similar points, dating to more than 12,000 years ago, have been discovered across the continent.

Searching the Past

At the annual Archaeological Field School, students dig, scrape and catalog artifacts in their journey to understand North America’s earliest people.Read more…

However, in the Far West, the oldest points lack distinctive Clovis trademarks. They do not contain fluted channels and appear to have been made by a different method. They are about the same age as the oldest Clovis points but may have been made by another culture. Archaeologists call it the Western Stemmed Tradition.

“Cooper’s Ferry contains a lot of information about the Western Stemmed Tradition. It’s a series of technological patterns that extends from British Columbia to northwestern Mexico and seems to be an economic lifeway for food gathering and tool production,” says Davis. “We think the Western Stemmed Tradition may represent a separate cultural pattern that’s present in the Pleistocene before 10,000 years ago and may be a cultural manifestation of a totally different people than Clovis.”

Digital Dig

As specialists in prehistory — human activity before the advent of written records — archaeologists wrestle with two major problems. First, their science is based on evidence embedded in an evolving landscape and deposited by people who left precious little else. The story is inherently uncertain and open to interpretation. Second, as they dig through layers of soil and remove objects, they destroy the actual record that accumulated as people came and went over thousands of years.

Landmarks near Cooper's Ferry on the lower Salmon River could have guided early people through a post-ice age landscape. (Photo: Loren Davis)

Landmarks near Cooper’s Ferry on the lower Salmon River could have guided early people through a post-ice age landscape. (Photo: Loren Davis)

The solution for Davis and his colleagues lies with the latest information technologies. They have created what amounts to a virtual dig site that can be widely shared in great detail, right down to replicas of the artifacts themselves. The methods they are using at Cooper’s Ferry are as far removed from the first studies at Clovis as modern people are from those early hunter-gatherers along the lower Salmon River.

Like detectives at a crime scene, Davis and his crew work hard to preserve evidence. As they remove soil by the bucketful and extract objects with surgical precision, they photograph every step of the way. They use a modern survey instrument known as a “total station laser transit” to pinpoint the location of every significant feature — debitage, mussel shells, bones, projectile points, soil layers, even rodent burrows. With a hand-held X-ray device, they analyze soil composition around the artifacts. And high in a shade-making tarp suspended over the dig site, cameras snap photos minute by minute. They produce about 9,000 images per day.

“These photos can be strung together in time-lapse movies,” says Davis. “I can’t be everywhere at the site, and if I have a question about an event, I can go back and watch the time-lapse and see what happened.”

Then there’s the Cooper’s Ferry Wide Web. Through computers set up in a trailer at the site, this Intranet system allows researchers working simultaneously in a half-dozen small plots to record information about every object they find. As they work, each team logs in with a laptop, enters data and even prints unique labels for the artifacts they have collected.

“We find so many items, we would get bogged down with the analysis if we didn’t develop these systems,” says Davis. “When you do it the 15th century monk way, with a paper and pencil, you get repetition. With this system, you can have simultaneous users, and the server keeps it straight. It gives unique numbers to each person so you don’t get overlap. We don’t have to clean the data later. It saves a lot of time.”

Researchers recovered these prismatic blades and core fragments (stages in the production of finished stone points and tools) at Cooper's Ferry. (Photo: Loren Davis)

Researchers recovered these prismatic blades and core fragments (stages in the production of finished stone points and tools) at Cooper’s Ferry. (Photo: Loren Davis)

Knowing where artifacts accumulated over thousands of years is key to understanding how people lived at Cooper’s Ferry. “We have a tremendous amount of spatial data. That’s the majority of what we do when we’re excavating,” explains Davis. “Things are found in space longitudinally and in association with other objects.”

Such detailed documentation enables the OSU researchers to share evidence with colleagues, students and the public. They have even employed a student to produce videos displayed on a Cooper’s Ferry YouTube channel (youtube.com/user/CoopersFerry­Site). “Archaeology is generally not all that transparent,” Davis adds. “You either have to be there or you have to take my word for it. Or you can go see artifacts in a museum.”

In addition to the photographs, soil chemistry and spatial data, Davis and his team benefit from the advent of 3-D printing. With a $100 digital scanner used by computer gamers, they scan artifacts in the field. They process the resulting images into files that can be sent to a 3-D printer for creating accurate physical replicas. Now, other scientists and students can learn, not just from reports and photos, but from their own hand-held inspection.

Reliable Resources

After Davis made his landmark find in 1997, it took him 12 more years to go back. It wasn’t for lack of interest. He needed the support for what he expected to be a multi-year effort. That arrived in 2008 when Joseph Cramer, a retired oil geologist with a keen interest in North American archaeology, gave $1 million to Oregon State to establish the Keystone Archaeological Research Fund. Davis directs the fund and says it was key to starting work at Cooper’s Ferry. It provided critical backup, for example, when BLM funds were cut in 2012 as a result of the federal budget deal known as sequestration.

In that same year, Davis and his students located a trench dug in the early 1960s by archaeologist B. Robert Butler of the Idaho Museum of Natural History. In re-opening it, they found pull-tab beer cans (Lucky, Buckhorn and Rainier) and other modern artifacts, but more importantly, they found that Butler had stopped short of the deepest, earliest archaeological deposits. Digging further, the Oregon State scientists found the wolverine skeleton and the nearby pit with 13 projectile points.

People with even longer ties to Cooper’s Ferry are also uppermost in the minds of Davis and his colleagues. The Nez Perce (Nee-Me- Poo) National Historic Trail crosses the lower Salmon River and marks the desperate flight in 1877 of 750 men, women and children from the U.S. Cavalry across some of the most difficult terrain in the West. It stretches for 1,170 miles through Oregon, Idaho, Wyoming and Montana.

Davis and his collaborator, archaeologist David Sisson of the BLM, also an Oregon State alumnus, have attended Nez Perce tribal council meetings to discuss their procedures and findings. “We try to keep them informed more than anybody,” says Davis. ”We get visits from tribal members. They’re intrigued about what we’re finding.”

A West Coast Story

It’s likely that occupation of Cooper’s Ferry didn’t start with the people who left the four points that Davis found by the river in 1997. Older sediment layers just below those points are waiting to be explored but have already yielded objects. “We may have a much deeper time span than we realized,” he says. “It’s a little like doing Wheel of Fortune. We’ve only turned one or two tiles, so it’s hard to guess the whole thing. We just need to keep opening up more to figure things out.”

CF-green-obsidian-4-part-copyBesides going deeper in time, the Cooper’s Ferry research may expand the Western narrative about how early people came to North America and how they lived and reacted to a changing landscape. That’s because the tools and points found there show links to people at other locations in the region, places such as Paisley Caves, Lind Coulee in Washington, and Baja California, Mexico. Western Stemmed Tradition points have been found in each.

Davis has focused part of his efforts on the Oregon coast. In a project that could point the way to future investigations in coastal waters, he created a map of what the near-shore environment would have looked like at the height of the last ice age, when sea levels were almost 300 feet lower than they are today. If early people occupied coastal sites, he says, much of what they left behind would now be underwater. Based on bathymetric surveys, he mapped likely river courses and locations where people might have lived. His maps already play a role in the U.S. Bureau of Ocean Energy Management’s permitting process for near-shore development.

At Devil’s Kitchen State Park near Bandon, Davis has found artifacts in buried deposits that range between 6,000 and 11,000 years old. The site is unusual because the land on which it sits is rising relative to sea level. “It’s a preserved river valley that didn’t get submerged. This is an example that is normally buried deep in sediment,” he says.

If people from a non-Clovis culture walked from Asia to North America at the height of the last ice age, they would have run smack into an ice sheet that blocked their way east. It’s possible that, as ice-free corridors opened later, they moved south along the long-submerged coastline and through inland river valleys.

It’s unlikely that as such opportunities became available, Davis thinks, people would have sat in Alaska twiddling their thumbs until the ice sheet had fully collapsed. The Copper River valley, for example, opened early, and people could have walked from the Yukon to the ocean. “Is that what happened? I don’t know,” he adds. But he’s walking down his own trail to find out.

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