After grueling hours of meticulously scraping away soil inch by inch, Jake Milroy saw a shattered edge emerging from the dirt. Soon, he gingerly held a pottery fragment as big as his hand, last touched by humans between 600 and 1,000 years ago.

“It was pretty crazy, having that material connection to ancient people,” says the University of Oklahoma anthropology senior. “It’s such a real, tangible thing.”

Milroy was one of 22 students from OU and as far away as Atlanta’s Emory University participating in the OU Field School in Archaeology, offered by the Dodge Family College of Arts and Sciences’ Department of Anthropology and the Oklahoma Archeological Survey, or OAS. The group spent a month in Oklahoma’s early summer heat and rain to answer one enduring question: Who were the Spiro people?

Spiro Mounds lies nestled in a bend of the Arkansas River in eastern Oklahoma and is considered among the most important U.S. Native American archaeological sites. 

Spiro Mounds Archaeological Park’s 12 mounds were extensively documented by OU researchers starting in the 1930s. They discovered a world of artistry and ceremony based upon a broad trade network and a highly developed religious center. Thousands of Spiro artifacts are studied at U.S. museums ranging from the Smithsonian Institution to OU’s own Sam Noble Oklahoma Museum of Natural History.

OAS Director Amanda Regnier says Spiro sat at the pinnacle of a prehistoric political system networking communities within the Mississippian culture. The site was occupied from roughly A.D. 900 to A.D. 1450, with people across the Southeast gathering in Spiro for at least 300 years.

“We have evidence that massive pilgrimages were held,” she says. “We know a great deal about Spiro’s mounds, but we don’t know who lived at Spiro year-round or what their daily lives were like.” 

Clues are emerging that Spiro’s religious and burial sites were maintained by a small community of permanent residents. OU researchers and students are sifting through layers of the earth looking for traces of them.

The Spiro Landscape Archaeological Project started in 2011 with gradiometer scans of the site’s non-forested areas. “Near-surface geophysical equipment let us see what’s beneath the surface of the ground without having to excavate,” Regnier says.

The research team sought anomalies. “Any time humans churn up soil, whether it’s to build a house or burn garbage, they alter its magnetic value,” she adds. “We use a gradiometer to detect those changes.”

Periodic excavations began at Spiro in 2013. OU continued its work this May when survey staff and students dug some 30 6-foot-by-6-foot excavation units in three different areas of the Spiro site, all while battling record rainfalls.

“The weather was, without a doubt, the biggest challenge,” Regnier says.

Despite soggy conditions, teams headed out daily from residence halls at the nearby University of Arkansas-Ft. Smith. On site, two students would kneel or lie flat to dig four-inch levels in each excavation unit while gathering samples, screening buckets of dirt and writing descriptions of discoveries. Student teams excavated an average of two levels—eight inches—each eight-hour day.

“People’s image of archaeology is some guy with a brush dusting bones off,” Regnier says. “But we explain to students at the outset, ‘Fieldwork is manual labor in the hot sun.’ ”

Milroy doesn’t mind. “I didn’t expect to be so immersed in the experience,” he admits. “Being involved with a genuine, hands-on research project has been a core experience in my college education.”

For students like Milroy, who hopes to become a cultural resource manager, OU’s field school offers an undergraduate research opportunity and meets an accredited requirement for future jobs.

Milroy worked under OAS Senior Researcher Scott Hammerstedt, whose team uncovered traces of a potential house and communal trash pit, or midden. Previous work by OU researchers found signs of a 20-foot-long wall typical of a Spiro home and evidence of as many as 25 houses.

After more than 600 years of decay, such evidence is often just a ghostly imprint.

 “For instance, if there’s a round, dark stain in the soil, that could be a post hole or a pit someone dug,” Regnier says.

Other evidence is clearer. The large pottery fragment Milroy unearthed and multiple others were found within the home’s footprint, bringing Spiro alive for the Tulsa, Okla., native. “I found myself trying to imagine where that pot might have been stored in the house and how it was used,” he says.

Close examination of the fragment also yielded a surprise. “Most of the artifacts we’ve been finding date to between 1050 and around 1250,” Hammerstedt says. “This looks like it might be from around 900 A.D.”

Another thrilling find came from the same site and era—two pierced beads, one made from clay and fired into a ceramic and the other fashioned from black phosphate found in limestone, burnished to a shine evident even today.

Nearby, OU Department of Anthropology Chair Patrick Livingood and his team uncovered evidence of a small structure that may have served as a temporary building for Spiro pilgrims. Gradiometer scans indicate traces of dozens of similar buildings at Spiro.

“Temporary buildings are an unusual ancient architectural form,” Livingood says. “Only a handful have been documented historically and archeologically.”

Regnier’s own group excavated buried, communal middens revealing ancient traces of debris and food, including squashes and sunflowers. “This gives us an idea about diet. From pieces of animal bones, we can tell that people at Spiro also ate a lot of turkey and fish,” she says, adding that Hammerstedt’s team found a large set of bones that may be deer remains.

“But across the three sites, the main things we found were debitage—debris from making stone tools,” Regnier says. “The Spiro people were going down to the river and getting cobbles of chert or other knappable stone to make tools.”

Field school students had a chance to try their own hand at flintknapping during downtime at the University of Arkansas at Ft. Smith. “It made me realize how difficult knapping is and really appreciate the skills of ancient Native craftsmen who made projectile points,” Milroy says.

Projectile points and hundreds of other artifacts like debitage, charcoal and liters of soil samples from each excavation unit were taken to OAS for laboratory study by OU students and experts, including Senior Researcher Jennifer Haney, a paleobotanist who will run soil samples through flotation testing to identify plant remains. Pottery will be examined for design and chemical makeup.

Thus far, Regnier says, findings have led team members to a few early conclusions. 

“Spiro probably never had a large population,” Regnier says. “The thing that’s really interesting is most of the activity at Spiro occurs in a small window, from about 900 to 1200 A.D. As ceremonialism and rituals increase, there are fewer people living at Spiro.”

Sometime in the mid-1400s, traces of Spiro occupation disappear altogether, likely due to a 100-year drought researchers believe changed the Spiro way of life. The OU researchers established a memorandum of understanding with both the Caddo Nation and the Wichita and Affiliated Tribes. Adult and youth tribal members visited the field school to learn more about their ancestral history, which scientists surmise is connected to the Spiro diaspora.

Research results, treasured finds and decades of work aside, Regnier believes the best evidence from OU’s Field School in Archaeology can always be found in the present.

“The most rewarding thing is getting to teach the students and hear some of them say, ‘Oh my gosh, this is it. This is the thing I want to do with my career and love the most.’ ” 

Anne Barajas Harp is editor of Sooner Magazine.

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