Identification of the Sources of Hopewellian Obsidian in the Middle West

One hundred and twenty years ago, the first obsidian implements were reported from Hopewellian mounds by Squier and Davis (1848). Since that time, a number of regions have been suggested as the source area: Alaska, the Pacific Coast, Yellowstone National Park, New Mexico, and central Mexico. Neutron activation analysis of the elemental composition of Hopewellian obsidian indicates two separate element groups. One of these, the 150 Group, has its source at Obsidian Cliff in Yellowstone. The second, the 90 Group, is also located in Yellowstone, but the exact flow has not yet been discovered.