Although monumental earthworks can be found from southern Canada to Florida and from Wisconsin to Louisiana, Ohio has the largest collection of these structures in the United States, despite the fact that Ohio has no federally recognized Indian tribes. Their creators were united under the vague term “Hopewell Culture”, named after the family on whose rural land one of the first mounds was discovered. Cultural activity associated with Hopewell is thought to have ceased in the Ohio region around 450-400 BCE. Tribes such as the Eastern Shawnee, the Miami Nation, and the Shawnee, who historians believe are most likely the modern-day descendants of the mound builders, were forcibly displaced by the European genocide of the continent’s indigenous population and now live on reservation lands in Oklahoma.
Glenna Wallace, chief of the Eastern Shawnee tribe, is one of those descendants. When we spoke, Wallace was on her way to Washington, D.C., to meet with President Joe Biden at the White House Tribal Nations Summit. These annual events were first convened in 2009 by President Barack Obama, but were discontinued during the Trump administration. Wallace had just recently returned from southern Ohio, where she had been visiting places connected to her tribe’s ancient roots. “The Native American voice has not been very strong in Ohio. What our people achieved there didn’t necessarily get the best protection there could have been,” she told me. “People were forced to leave, and our burial mounds are not maintained.”
Burks and I drove about 70 miles southeast of Columbus, along winding highways lined with creeks and roadkill, to reach a small family farm in the foothills of the Appalachian Mountains. The trees around us were covered with autumn leaves. A herd of cattle wandered past, their muscular backs framing the hills in the distance. As Burks completed the 20-minute process of assembling his magnetometer—when completed, it would form a cart nearly seven feet wide and weighing about 30 pounds—he emphasized that the vast majority of the artificial hills and mounds he spends his time searching for had been physically dismantled long ago. In only a few cases have these earthen fortifications been excavated or studied for the first time; instead they were simply plowed over; use bulldozers to build roads, houses and shopping centers; or, in one infamous case, incorporated into the landscaping of a local golf course.
Archaeologists believe that these earthen fortifications functioned as religious gathering places, tombs for culturally important clans, and annual calendars, perhaps all at the same time.
Until recently, it seemed that much of the continent’s pre-European archaeological heritage had been carelessly destroyed, uprooted and lost forever. “When people see the plowing, they think the archaeological sites are completely destroyed,” Burks said, “but they’re still there.” Traces remain: electromagnetic residues in the soil that can be detected with special surveying equipment. Here, in this very pasture, he added, there were once at least three round enclosures. Our goal that morning was to find them.
Magnetometry – Berks’ specialty – is able to register even tiny changes in the strength and orientation of magnetic fields. When pressed across the landscape, the magnetometer can detect where these fields in the soil below have changed, potentially indicating the presence of an object or structure such as old walls, metal implements, or filled-in pits that may be graves. Magnetometry is also extremely good at finding bonfires or bonfires, the heat of which can permanently change the magnetism of the soil, leaving behind visible signs. This means that even apparently empty pastures – or, indeed, public golf courses and suburban yards – can still contain magnetic evidence of ancient settlements, invisible to the naked eye.
In this context, the first hurdle is knowing where to start scanning. Fortunately for archaeologists and tribal historians alike, Ephraim George Squier and Edwin Hamilton Davis—a two-man team working in the mid-19th century—mapped as many excavations as they could find, motivated to learn more about these artificial landforms before they were destroyed or forgotten forever. Explaining the rationale of their project, the authors wrote that the excavations received only passing descriptions in the journals of other travelers and, in their opinion, “need to be more carefully and in detail, and above all, more systematically investigated.” They hoped that in this way they would “shed some light on the grand archaeological questions connected with the primitive history of the American continent.”