What started as a routine survey of the land surrounding a historic bridge has ended up unearthing two significant sites in Missouri, USA. Larry Grantham, an archaeologist with the Missouri Department of Transportation, said his team has discovered a pair of Native American sites bookending the 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, dating to the late Archaic period.
     At the late Woodland site, which dates to roughly 650 to 900 CE, the group is looking for evidence of structures. 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." He said cooking pits and storage pits also are likely to turn up.
     The late Archaic site, which dates to roughly 3000 to 1000 BCE, is yielding 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. "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." 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.

Edited from Which.com (11 November 2011)