Sometimes archaeological discoveries are made in places where you least expect them. That was certainly the case for a research team from the University of Michigan, whose discovery and subsequent work was summarized in the Proceedings of the National Academy of Sciences.
Thanks to an effort six years ago to update government maps, features were discovered that revealed evidence of ancient hunting methods - on a ridge under approximately 120 feet of water off of Lake Huron near the Michigan coast.
The underwater ridge, known as the Alpena-Amberley Ridge, is located approximately 35 miles from Alpena, Michigan, in an area that was a land connection between Michigan and Ontario, Canada some 9,000 years ago. Using initial guidance from the map and following up with sonar, drones, and scuba divers, the group from Michigan located a group of ancient hunting structures and artifacts from the Late Paleoindian and Early Archaic period.
The main structure is unusually intricate - more so than any other known structure beneath the Great Lakes. This particular structure is known as "Drop 45".
Parallel rock lines with an overall funnel shape forced wildlife toward a naturally formed cul-de sac, with hunting blinds that were created within the stone lines and various obstructions designed to direct the caribou into areas where they could be easily harvested. Separate rock formations served as circular hunting blinds to further conceal the hunters from the caribou.
The positioning of the features allowed the research team to draw some conclusions about the seasonal hunting habits of the natives. While the best season for caribou hunting would have been in the fall, the features were aligned such that it would only be effective when the caribou were traveling northwest. Northwestern movement would coincide with the spring migration as the climate warmed up.
By itself, that information isn't very surprising, except that other hunting blinds in a V-shape that are located upslope from the Drop 45 location are facing the opposite direction - designed to conceal hunters from caribou during the southeastern migration in the fall.
With different types of hunting structures oriented to different hunting seasons and migration patterns of caribou, it's logical to assume that at the time of these structures that the land bridge was a convergence point for caribou migration in both directions. This made it an efficient place for hunters of the day to create their structures.
The research team also noted their great fortune in finding this site underwater - had it been on the land surface, it almost certainly would have been disturbed, if not destroyed outright, by farming and other forms of human development. The remarkable amount of preservation offered by Lake Huron retained more delicate artifacts such as chipped stone debris that allowed the team to draw further conclusions about the culture of the hunters, as well as their organizational methods.
Perhaps there are other fields and artifacts preserved in the cold waters of Lake Huron, waiting to be discovered so that they can reveal their secrets. If so, the Michigan team and other researchers will be at the ready to study them.