MICHIGAN: Flakes from 9,000-year-old obsidian tools were recently recovered from a Paleoindian hunting site that now lies more than 100 feet under Lake Huron. Obsidian, a black volcanic glass, was a prized resource used by members of ancient cultures to make sharp tools. There is no local obsidian source. Researchers traced the origins of the obsidian used in the tools to a quarry in central Oregon, 2,500 miles away. This suggests that an extensive trade network existed toward the end of the last Ice Age.