Mima mounds in North America are primarily known from the western states of Washington, Oregon, and California; the Rocky Mountains; the mid-lower Mississippi Basin; and Louisiana-Texas Gulf Coast. By contrast, their former extent and abundance across the Upper Midwest prairie belt has never been systematically established due to their destruction by agriculture and historic confusion as to whether they were natural or anthropic mounds. Recent maps showing their distribution identify only two small moundfields, one centered on Waubun Prairie in western Minnesota, the other on Kalsow Prairie in north-central Iowa. But in fact, natural mounds were once a common feature of many Upper Midwest prairies, having extended from Kansas, Missouri, and Illinois north into Wisconsin, Iowa, Minnesota, the Dakotas, and across the prairies and parklands of Canada. Several remnant tracts, intact and preserved, bear witness to their former much greater extent. This chapter documents the original distribution across the prairie belt, which has implications for their origin insofar as it falls more or less entirely within the range of the Geomyidae (pocket gopher) family of fossorial rodents. Natural prairie mounds in the Upper Midwest invariably are found where limitations to vertical burrowing occur, or did occur, which leaves lateral burrowing as the only option to these and other soil animals. Owing to extensive overlaps between natural mounds and morphologically similar prehistoric “Moundbuilder” mounds, the idea is advanced that prairie mounds were opportunistically used for prehistoric interments, and later as ideation templates for prehistoric burial, effigy, and other mounds and utilitarian structures.

ABSTRACT On a regional geological map, western Wisconsin looks as if it has very simple, even boring, geology. It is dominated by flat-lying, layer-cake Ordovician sedimentary rocks thinly overlain by Pleistocene glacial drift, yet detailed investigation reveals many interesting geologic features, furnishing research projects and teaching examples for all levels of geological education. In this “simple” area around Spring Valley, Wisconsin, you will see a major cave, an old mine, a large earthen dam and a meteorite impact site. In addition to what these sites say about the area’s geologic and human history, they furnish insight into how geologists piece together evidence as well as illustrate relevant subjects such as groundwater supply, control of catastrophic flooding and intelligent land use. It is our hope that, while enjoying learning about the features in this scenic part of Wisconsin, many of you will be inspired to seek out the unique geology of your area, and bring that knowledge into your classrooms.