Travel Reference
In-Depth Information
Wisconsinwasonceattheearth'sequatorialbeltbuckle.PlateshiftingcreatedtheCanadian
Shield, which includes about two-thirds of eastern Canada along with Wisconsin, Min-
nesota, Michigan, and New York. A half-billion years ago, a glacial lake flooded the Wis-
consin range—the northern section of present-day Wisconsin.
Glaciation during the two million years of the four glacial periods—geologically, a
blink of an eye—is responsible for Wisconsin's one-of-a-kind topography. (The final ad-
vance,occurring70,000-10,000yearsago,wasevennamedtheWisconsinperiod.)Wiscon-
sin endured five glacial “lobes” penetrating the state, reducing the state's previous ambi-
tious heights to knobs and slate flatlands and establishing riverways and streambeds. Only
the southwestern lower third of the state escaped the glaciers' penetration, resulting in the
world's largest area surrounded completely by glacial drift.
Northern Highland
Covering 15,000 square miles, the Canadian Shield is the most salient physiogeographical
feature of northern Wisconsin. Underlain by crystalline rock on a peneplain, the bedrock
and glacial soils are particularly suited to growing timber.
This area's high concentration of lakes is what separates the region from the rest of the
Midwest—and, in fact, distinguishes it in the world, since only the remotest parts of Que-
bec and Finland have more lakes per square mile.
Lake Superior Lowlands
Wisconsin's northern cap along Lake Superior displays a geological oddity, unique in the
Great Lakes—a fallen trench of Lake Superior, flanked by palisades. Before the glaciers
arrived to finish carving, shifting lowered this 10- to 20-mile-wide belt (now a half-mile
lower than the surrounding land). This wedge-shaped red-clay plain consists mainly of
copper-hued outcroppings and numerous streams and rivers, as well as waterfalls.
Eastern Ridges and Lowlands
BorderedbyLakeMichiganontheeastandnorth,this14,000-square-mileregionwasmuch
richeringlacialdeposits,andthefecundsoilsattractedthefirstimmigrantfarmers.Theim-
peded waterways were ideal conduits for floating timber to mills.
The Kettle Moraine region southeast of Lake Winnebago is a physical textbook of gla-
cial geology.
