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Fort McCoy has archaeological sites within its boundaries that represent more than 10,000 years of history.
Most of the artifacts from those sites which pre-date European contact are either stone tools or chips of stone removed while shaping stone tools. These stone chips, which archaeologists refer to as flakes (singularly) or debitage (collectively) are removed from specific types of stone by a process known as flintknapping.
This process involves striking stones in a precise way to remove pieces that will eventually leave behind the desired tool, be it a spear point, arrowhead, knife, or other type of stone tool. Naturally, the first step in making a stone tool is acquiring a type of stone which is suitable for making a tool.
The installation lands contain two adequate tool stone types which comprise the vast majority of the debitage recovered during archaeological investigations: Prairie du Chien chert and silicified sandstone. Prairie du Chien chert forms geologically in limestone and dolomite beds found primarily along the Mississippi River corridor, but there are remnants of such Prairie du Chien outcrops within Fort McCoy lands on the east side of South Post.
Silicified sandstone forms as sandstone beds become more mineralized as water leeches out loose sediments and replaces it with silica. Silicified sandstone outcrops and deposits are most prevalent in the north end of the installation.
While these two types of tool stone are the most common materials recovered at Fort McCoy, they are far from the only types of tool stone found.
Other types of tool stone recovered at Fort McCoy include materials which come from eastern and northern Wisconsin, Minnesota, Iowa, Illinois, and North Dakota. The differences in the materials include different colors and quality of the tool stone.
Materials like rhyolite and quartz can be used to make tools, but cannot produce fine, sharp edges as easily as cherts or silicified sandstones.
Another type of tool stone which is locally available in North Dakota is Knife River Flint, which can produce a very sharp edge, and tools made from this material have been found at Fort McCoy in very limited quantities.
The main source of Knife River Flint is more than 500 miles away from Fort McCoy, and like other materials from around Wisconsin, Minnesota, Iowa, and Illinois, would have been intentionally carried to Fort McCoy from wherever it was found.
This practice was likely more common in the earliest days of people interacting with the Fort McCoy landscape, as early hunters and gatherers would travel hundreds of miles during their seasonal rounds following resources such as game and forage foods.
As early as 1,500 years ago, however, exchange or trade networks were employed which spanned more than half the country, and this was another method by which tool stone from hundreds of miles away could have ended up in the hands of people at Fort McCoy.
Researchers from Colorado State University’s Center for Environmental Management of Military Lands partnered with scientists from the Office of the State Archaeologist and the Department of Anthropology at the University of Iowa to undertake a study using X-ray florescence (XRF) to analyze 327 stone flakes from 37 archaeological sites located in Fort McCoy to determine where the original stone came from.
The device used for this study analyzed the chemical makeup of the flakes and could differentiate between proportions of trace elements within the flakes, which the scientists at the University of Iowa suggested could help narrow down the origin of specific materials to their geological formation.
The potential exists to be able to narrow this to the state level and beyond, possibly on a county-by-county basis as the techniques become more commonly used and refined and more reference samples are studied. Unfortunately, the XRF process requires reliably sourced comparative samples in order to confirm sources, and these comparative samples were not readily available to researchers performing the analyses. This left the results of the study to focus on the differences of trace elements present within the archaeological samples rather than confirm the source of the samples outright.
The XRF analysis was able to confirm that several specimens which were initially identified as “exotic” chert by the CSU researchers who recovered them were not from Wisconsin, but rather from at least 240 miles away from Monroe County, Wisconsin.
Tracking the origins of tool stone helps researchers better understand the movements of pre-contact peoples around the region as they travelled to and from the area now known as Fort McCoy, as well as how those who stayed in and around Fort McCoy interacted with people from other places.
All archaeological work conducted at Fort McCoy was sponsored by the Fort McCoy Directorate of Public Works Environmental Division Natural Resources Branch.
Visitors and employees are reminded they should not collect artifacts on Fort McCoy or other government lands and leave the digging to the professionals.
Any individual who excavates, removes, damages, or otherwise alters or defaces any post-contact or pre-contact site, artifact, or object of antiquity on Fort McCoy is in violation of federal law.
The discovery of any archaeological artifact should be reported to the Fort McCoy Directorate of Public Works Environmental Division Natural Resources Branch.
(Article prepared by the Fort McCoy Archaeology Team.)
| Date Taken: | 01.10.2025 |
| Date Posted: | 01.10.2025 14:40 |
| Story ID: | 488921 |
| Location: | FORT MCCOY, WISCONSIN, US |
| Web Views: | 9 |
| Downloads: | 0 |
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