During excavations at the Middle Woodland La plant I site (23NM51) on Barnes Ridge in New Madrid County, Missouri, a single obsidian artifact was unearthed. Obsidian artifacts are rare in Missouri and no Missouri obsidian artifact has previously been characterized by trace element analysis. Because of the potential significance of this find, the artifact was subjected to nondestructive XRF analysis at Northwest Research.

The artifact is a small obsidian flake (22 mm x 17 mm x 3 mm thick) that exhibits some polish that may be interpreted as evidence of prehistoric bag wear incurred during transport. Trace element analysis of the artifact (see the figure below) indicates that it originated from the well-known Obsidian Cliff source located in Yellowstone National Park in Wyoming. The source locality is over 1100 airline miles (1760 km) from the La Plant I site and over 1800 miles (2880 km) if riverine routes were used. Although it is likely that the acquisition of the obsidian was associated with the extensive Hopewell procurement systems of the Middle Woodland period, we can still only speculate as to whether the glass made its way to the La Plant I site through direct long-distance procurement or through exchange with groups inhabiting the Hopewell periphery.