In 1960 and 1961, Ronald J. Mason and Carol Irwin Mason excavated two sites on the Door Peninsula in Wisconsin's Door County. The Mero site and the Heins Creek site contained many artifacts, including pottery, chipped and ground stone, copper, and bone. Mason named the earliest component at the Mero site North Bay I and considered it a late phase of the Middle Woodland period, with clear links to Hopewell and Point Peninsula cultures.