Archaeology: Interstate Park’s ancient copper tool and extinct bison bones posed a millennia-old mystery

Park workers dug up objects in the 1930s that raised questions about when people first lived in what’s now Wisconsin.




5 minute read

Via the Wisconsin Historical Society. Republished with permission.

Hammered copper pike, c. 1000-4000 B.C. (Wisconsin Historical Society)

In October 1936, Civilian Conservation Corps (CCC) workmen found a hammered copper pike during excavation of a peat deposit at Interstate Park in northwestern Wisconsin. The pike measured almost 11 inches in length, had tapered ends, and was made of native copper.

While partially encased in peat, which had hardened around the pike during its long burial in the marsh, its exposed ends remained bright and shiny despite having been entombed for thousands of years.

Two months earlier, workers at the same site had found bones from the extinct Bison occidentalis, a species of bison then believed to have been extinct for 10,000 to 12,000 years. The discovery of a man-made tool alongside bones of such antiquity suggested that humans had lived in Wisconsin much earlier than most scientists had believed and that these people had possibly hunted the bison.

The excavations at Interstate Park, c. 1936. Note the water in the excavation pit. Seepage made it necessary to pump out the pit on a daily basis. Source: A.W. Pond from the Alonzo W. and Dorothy L. Pond papers. Image use courtesy of Chomingwen and Arthur Pond. View the original source document: WHI 41921

European settlers in the mid-nineteenth century first began to find copper tools in Wisconsin almost as soon as they began to break the soil for farming. At the time, some scholars attributed the construction of these copper implements to a vanished race of peoples that had occupied the region prior to the Native Americans the Europeans had found living there.

After additional research and discoveries, however, by the early twentieth century the arguments over the people responsible for making these artifacts had been resolved in favor of the Native Americans. Nonetheless, archaeologists still did not know how the copper tools had been made or how old they were.

With the discovery of this copper pike commingled with extinct bison bones, the mystery regarding copper artifacts took an unexpected twist. Only a decade before the Interstate Park site excavations, stone tools had been found associated with the same species of extinct bison at Folsom, New Mexico.

After careful scrutiny, scientists determined that the Folsom artifacts proved that humans had settled the Americas in the late Pleistocene epoch, at least as early as 8000 B.C.

In light of the conclusions from Folsom, the excavation of the bones at Interstate Park took on a new importance. The discovery of the copper pike and, shortly thereafter, two stone projectile points, suggested that the Interstate Park site was also very old and that the bison had been hunted for food by Native Americans living in the area.

In 1937 Alonzo Pond, the project superintendent of the CCC project at the time of the pike’s discovery and a former archaeologist at Beloit College, spoke at the joint meeting of the Wisconsin Archeological Society, Wisconsin Academy of Sciences, Arts, and Letters, and Wisconsin Museum Conference, telling those present that the pike, owing to its association with a species of bison believed long extinct, argued for great age for the site, perhaps 10,000 to 12,000 years old.

Pond’s claim was largely ignored until the mid-1950s when geologist Harris A. Palmer reexamined the bison bones, confirming that they were, indeed, the extinct Bison occidentalis. By this time, radiocarbon dating had been developed and scientists had used it to date two sets of Bison occidentalis bones from a site in Wyoming to approximately 4320BC to 5530BC, dates much more recent than previously assumed.

Bison occidentalis skeleton on exhibition in the Ice Age Gallery of the Milwaukee Public Museum. This skeleton is a reconstruction made from bones from several different bison found at Interstate Park as well as a few plaster casts. Source: Image courtesy of Matt G. Hill

By the mid-1950s, archaeologists with the Wisconsin Historical Society and Milwaukee Public Museum had also determined two new dates for the Old Copper Complex, as the array of heavy, utilitarian copper tools had become known. When combined, their research put the dates for Old Copper between 3250 B.C. and 5900 B.C.

Research now indicated that copper had been used by numerous Native American groups over thousands of years and scientists speculated that these tools were the oldest man-made objects in the state.

Since the Old Copper dates differed little from those for the extinct bison, thoughts again arose that the bison at Interstate Park might have been hunted and killed for food, with the bones then disposed in the nearby marsh. Although never widely accepted, researchers no longer dismissed the association of the tools and bone, and it remained a viable theory.

Further scientific study, however, began to dismantle the possibility that the Wisconsin bison had been killed by human hunters. Researchers again reviewed the dates for the Old Copper Complex and more accurately determined the dates to range from 1000 B.C. to 4000 B.C.

Even more recently, a study compared the bones from the Interstate Park Bison site with known bison kill sites in western North America, which indicated that the age spread of the animals and overall composition of the Wisconsin assemblage is unlike that of any of the others. Moreover, none of the over 1,300 bones found at Interstate Park has any trace of cut marks from butchering.

Rather than prey for Native American hunters, the Interstate Park bison now appear to have died natural deaths, possibly starving to death in one of northern Wisconsin’s harsh winters. The carcasses may have later washed into the marsh and gradually been covered over with wind-blown and water-carried sediments, only to be exposed again by CCC workmen thousands of years later.

Bison bone (near front center) exposed at the time of the excavations. Wooden boards were laid on the floor of the site to keep the workmen above the muck and from crushing the fragile bones. Source: Photograph by A.W. Pond from the Alonzo W. and Dorothy L. Pond papers. Image use courtesy of Chomingwen and Arthur Pond.

It now seems that while humans likely left the copper pike and two stone tools shortly after the bison were deposited, they cannot be implicated in the deaths of these animals and were only associated by coincidence. Indeed, such pikes were used to chip holes in the ice for winter fishing, not hunting game.

In the end, scientific research showed that this copper awl was not as old as first believed. Other archaeological finds of distinctive fluted and lanceolate projectile points and other stone tools, however, have confirmed that humans settled in Wisconsin as early as 11,500 years ago. Also, while not a kill/butchering site, the Interstate Park Bison site remains important in understanding both early Holocene epoch bison ecology and human adaptations in the region, including the choice of prey.

  • By Marlin F. Hawley, Curator, Wisconsin Historical Society

[Sources: Pond, Alonzo W. “Wisconsin Joins the Ranks of Oldest Inhabited Areas in America” “The Wisconsin Archeologist” 17(3):51-54; Palmer, Harris A. “A Review of Interstate Park, Wisconsin Bison Find” “Proceedings of the Iowa Academy of Science” 61:313-319; Hill, Matthew G., Marlin F. Hawley, and Chris Widga. “Depression-Era Archaeology, Early Man in North America, and the Interstate Park Bison Site, Polk County, Northwestern Wisconsin” (unpublished manuscript, Department of Anthropology, Iowa State University, 2007).]


You may republish this article online or in print under our Creative Commons license. You may not edit or shorten the text, you must attribute the article to St. Croix 360 and you must include the author’s name in your republication.

If you have any questions, please email


Creative Commons License Attribution-ShareAlikeCreative Commons Attribution-ShareAlike
Archaeology: Interstate Park’s ancient copper tool and extinct bison bones posed a millennia-old mystery