Natural Prairie Mounds of the Upper Midwest: Their Abundance, Distribution, Origin, and Archaeological Implications

Natural prairie mounds (i.e., Mima mounds or pimple mounds), once common across much of North America west of the Mississippi River, have long piqued the interest of geomorphologists, pedologists, and archaeologists. An enormous geological literature has resulted since no consensus exists regarding their nature and origin. By contrast there is a small archaeological literature on this problem since archaeologists typically consider their primary directive accomplished whenever a possible mound is determined to be a non cultural feature.

Investigators have focused mainly on their southern occurrences in Arkansas, Louisiana, Texas, and Oklahoma, and western occurrences in California, Oregon, Washington, Idaho, Colorado, and Wyoming. Few contemporary researchers are aware that they were also common in the Upper Midwest—in Iowa, Minnesota, Wisconsin, Illinois—as well as in Missouri. Beginning in the late nineteenth century archaeologists (e.g., W.J. McGee, T.H. Lewis, Gerard Fowke) recognized the numerous prairie mounds in this region. Other researchers (e.g., David Bushnell, Edward Schmidt, Jacob Brower, Newton Winchell) adamantly insisted on a cultural origin hypothesis despite the near complete absence of any associated human-made artifacts.

Particular attention will be given to Lewis, a famous burial mound surveyor, who observed prairie mounds in Minnesota, Wisconsin, Illinois, Iowa, Kansas, Missouri, and Arkansas; Schmidt, a recorder of hundreds of prairie mounds in Minnesota; and Fowke, an active field archaeologist for the Smithsonian. The single largest probable prairie mound site is at Harpers Ferry, Iowa. At Harpers Ferry it is postulated that the Johnson and Johnson biomantle model and the Dalquest-Scheffer-Cox model of nest-centered centripetal rodent burrowing best accounts for the reported numerous prairie mounds. In summary this paper documents the former abundance and a much wider than previously known distribution of prairie mounds in the Upper Midwest and Missouri, and discusses their origin and archaeological implications.