Sunday, April 15, 2018

Call it Driftless Border

by Drew Hanson

There is a place in Dane County with many names including the Cross Plains Reserve, Interpretive Site, Ice Age Complex and Cross Plains State Park. None of these names speak to the uniqueness of this place which distinctly straddles the border between glaciated and unglaciated landscapes. I propose we call it Driftless Border.

By analogy, imagine Rib Mountain State Park instead called Wausau State Park. Or the person with several nicknames including some not so flattering. Names matter.

The Driftless Area is an expansive part of southwest Wisconsin that was untouched by Pleistocene glaciers. Most of the Driftless Area’s outline is subtle, especially to the untrained eye, partly due to the presence of older glacial deposits. In other places, the boundary of the Driftless Area is invisible because the glacial deposits that had defined its boundary were carried away by glacial meltwater or other erosional processes. However, in Dane County between Cross Plains and Verona, the Driftless Area is bordered by geologically young glacial deposits, giving this part of the Driftless Area a well defined border. Hence the name, Driftless Border.

This is not the first time the name Driftless Border has been used. It appeared in my 2013 article at https://pedestrianview.blogspot.com/2013/03/monumental-stepping-stone.html
and in 2015 at https://pedestrianview.blogspot.com/2015/01/the-best-hiking-in-dane-county-someday.html

The unique geology of the Driftless Border was well-known to University of Wisconsin geologist Fredrik Thwaites (1883-1961) whose 1908 master’s thesis described the geology of the Cross Plains/Verona/Middleton area. A biography of Thwaites appeared in Geoscience Wisconsin, volume 18 and is downloadable at https://wgnhs.uwex.edu/pubs/gs18a09/


I believe Thwaites’ knowledge of the Driftless Border and its national significance shaped National Park Service geologist Robert Rose’s review of Ray Zillmer’s proposed Ice Age National Park in Wisconsin. In 1961 Rose wrote:
“The driftless area of Wisconsin is world famous because it is an unglaciated area of considerable size … lying far within extensively glaciated territory… Several eminent geologists who have been consulted are unanimous in the view that a segment embracing a good example of the moraine-driftless area relationships is highly essential in illustrating the story of continental glaciation. With the completion of each field study, beginning with the initial reconnaissance of 1958, the desirability of including such a segment becomes more firmly recognized… The relationships between moraine and bedrock of sedimentary origin are most strikingly exhibited in an area of about 9,000 acres south and east of Cross Plains. Within this area rugged morainal ridges belonging to the Wisconsin [Glaciation] occur while the strikingly eroded margins of the driftless area lie immediately to the west and south. In brief, this key area is a self-contained unit scenically and scientifically.”
This is why this area became a unit of the National Scientific Reserve and underscores the rationale for the name, Driftless Border.

Naturally, the Driftless Border also needs a designation, such as state park, national reserve, national monument, etc. but that is for another discussion.

For additional information about the unique geology of the Driftless Border, see:
Geology of the Ice Age National Scenic Trail, David M. Mickelson, Louis J. Maher Jr., and Susan Simpson, University of Wisconsin Press, 2011; and
Ice Age Complex at Cross Plains, Final General Management Plan and Environmental Impact Statement, National Park Service, U.S. Department of the Interior, Wisconsin Department of Natural Resources, 2013.



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