More than 10,000 years ago, after the last glaciers retreated, people began living on the land now called Michigan, where caribou, mastodons, mammoths, and other animals roamed plains and marshes in a cool, wet climate. Anishinaabek (Odawa, Ojibwe, and Potawatomi) refer to these people and those who came after them as the Ancestors. The early Ancestors were mobile, adept hunters, fishers, and harvesters, and some camped on a sandy ridge near here now called Holcombe Beach. They used stone knives, projectile points, scrapers, and gravers, mostly made from regional Bayport chert. Archaeologists working in the early 1960s found distinctive fluted spearpoints and other tools left behind there, and a single bone from the site indicated that barren-ground caribou were part of the hunters’ diet. Archaeologists classify the earliest period of human history, more than 10,000 years before the present, as Paleo-Indian. In 1960, avocational archaeologist Jerry DeVisscher discovered Paleo-Indian artifacts at sites in this area, soon joined by Edward Wahla, and in 1961 University of Michigan archaeologists began excavating one site on an ancient beach ridge on the Holcombe Sod Farm. Later research determined that the lake associated with the beach ridge had disappeared well before people left the tools and bone that identify the site as one of the oldest in Michigan. In 1971 the Holcombe Site was listed in the National Register of Historic Places for its contributions to knowledge of the region's first people and of environmental change.