Archaeological collections from the Mound City and other sites show that the Hopewell culture had a trade network involving contacts with other groups that stretched from the Rocky Mountains to the Atlantic coastline. The obsidian was traded from sources a long-distance away (the closest known source is in the Obsidian Cliffs located in Yellowstone National Park in northwestern Wyoming). Other materials traded from long-distance sources include mica and slate from the Carolinas, copper from the upper Great Lakes region, and shells and sharks teeth from the Atlantic and Gulf coasts. Object constructed of silver and meteoric iron, and rare gold have also been found in association with ornaments and utility pieces from Hopewelll sites. The abundance and quality of the workmanship of crafted materials and artwork reflect the high level of organization the culture and government of the Hopewell society. The society was complex enough to support artisan and craftsmen dedicated to special skills.
