PALMYRA — What started as a routine survey of the land surrounding a historic bridge has ended up unearthing two significant sites in the region's Native American history.
Larry Grantham, an archaeologist with the Missouri Department of Transportation's Environmental Studies and Historic Preservation department, said his team has discovered a pair of Native American sites bookending the MO-168 bridge over the North River just west of Palmyra.
On the east side of the bridge is a 1,200- to 1,500-year-old site from the late Woodland period. The site on the west side of the bridge, however, is much older — 3,000 to 5,000 years old, dating to the late Archaic period.
The MoDOT archaeologists found the twin historical sites while conducting an archaeological survey around the 79-year-old North River Bridge, which will be replaced next year under the auspices of MoDOT's Safe and Sound Bridge Improvement Program.
The bridge itself has historic significance as the longest bridge of its type still in existence, and the State Historic Preservation Office is working to document its history and advertise the bridge components for adaptive reuse at a new location.
MoDOT's archaeologists, however, are more concerned with the ground itself, which will be significantly altered as crews even out the grade in the vicinity of the bridge.
"Anytime we have a project that involves earth disturbance, we go out and do an archaeological survey," Grantham said. "In this case ... they're going to raise the grade by 4 feet. On one side there's going to be a lot of cut, and on the other side there's going to be a lot of fill."
More than 3 feet below the ground's surface was evidence of the area's Native American history.
Given the differing time periods of the sites, their findings at each have been dramatically different.
At the late Woodland site, which dates to roughly A.D. 650 to 900, the group is looking for evidence of structures on the site. The Native Americans who inhabited that site were much less nomadic than earlier peoples, Grantham said.
"By the late Woodland (period), they're building houses, and they're being semi-sedentary," Grantham said. He said cooking pits and storage pits also are likely to turn up.
The late Archaic site, which dates to roughly 3000 to 1000 B.C., is yielding more of the artifacts that traditionally are associated with Native American digs. The archaeologists are hand-digging the site in 3-foot squares of just a few inches' depth.
Among the artifacts the archaeologists have turned up are projectile points, drills and other tools, all made from chert, a type of rock found along the Mississippi River.
That suggests to Grantham that the late Archaic inhabitants moved around the northern half of Missouri in a seasonal cycle, returning to Northeast Missouri for a short time to pick up their weapons materials. Chert wouldn't have been found in most of the interior of northern Missouri.
"Part of the seasonal cycle involves coming this far down to get chert to make tools with," Grantham said. "They're taking these chert (pieces), taking a lot of material off and making what we call pre-forms. They don't want to carry any more than they have to. They'll take a lot of flakes off it and get it close to a final form."
Grantham said there's also evidence to indicate that the late Archaic people in the region were heat-treating the chert to refine its quality.
As for the location of the camp, there is a spring on the west side of the North River. With Northeast Missouri's smaller tributary rivers and streams often flowing inconsistently, the spring would have provided a more consistent source of water, Grantham said.
Grantham and his team were evaluating artifacts recently in MoDOT's lab in Jefferson City. They will return to the area to continue their excavation.
This isn't the first time MoDOT archaeologists have found significant Native American heritage in the area. A survey in the vicinity of U.S. 61 in 2004 and 2005, at the beginning of the Avenue of the Saints improvements, turned up ancient Native American artifacts and resulted in numerous excavations along the highway in Lewis and Clark counties.