Geographers divide the State into five major areas, three of which lie in the belted plain covering all of central and southern Wisconsin. This belted plain is so named because it includes a ring of ridges, each with a short steep descent on one side and a long gentle slope on the other, marking the junctures of weak sedimentary rocks with more resistant, overlapping formations. Such ridges are called cuestas.
First of the three areas within the belted plain is the Western Upland, which begins in southern Polk County and widens southward until, at the Wisconsin-Illinois border, it extends from the Mississippi River to beyond the middle of the State. With elevations above sea level ranging between 900 and 1,200 feet, it has the highest altitudes of the belted plain. Two cuestas -- the Galena-Black River and the Lower Magnesian, of much greater length -- are salient land features in this region of 13,250 square miles. The Baraboo Ranges intersect the Magnesian Cuesta at Sauk County. A section of the Galena-Black River Cuesta, extending from Fennimore to Mount Horeb, is widely known as the Military Ridge. The Green Bay-Prairie du Chien Military Road, built in 1835, followed the crest of the cuesta. Other wellknown heights are Blue Mounds of 1,716 feet, highest point in southern Wisconsin, situated near Mount Horeb; and Platte Mounds and Sinsinawa Mound in the vicinity of Platteville.
Most of the Western Upland was never covered by the glaciers and therefore retained its early rugged landscape. But in the eastern part of the Baraboo Ranges the ice tore away huge blocks of the quartzite rock, deposited moraines, and created Devils Lake; in a region near the St. Croix and Chippewa rivers the glaciers deposited a thick drift. Nearly all of that portion of the Magnesian Cuesta which extends for 35 miles through Polk and Barron Counties is covered by glacial deposit. Drift left by some of the earliest ice sheets is spread throughout the Upland near Beloit and Monroe. The area north of the Baraboo Ranges affords good examples of glacial lake deposits.
Chief rivers of the Western Upland are the Chippewa, St. Croix, Trempealeau, Black, La Crosse, Wisconsin, and the Mississippi on the western border. The latter two have terraced their valleys and cut exceptionally deep gorges; the gorge of the Mississippi is cut to a point more than 500 feet below the level of the Upland Ridges. Interstate Park on the St. Croix River, Perrot, Merrick, and Wyalusing State Parks along the Mississippi, and Devils Lake and Tower Hill State Parks are regions of great natural beauty.
The province known as the Eastern Ridges and Lowlands covers 13,500 square miles in eastern and southern Wisconsin. Its western boundary reaches southwest from the Menominee River in Marinette County to the Wisconsin River in Sauk, thence southeast to the southern limit of the State in Rock County. The eastern boundary touches on Lake Michigan from the tip of Door County south to the Illinois line. Along this eastern boundary abandoned beaches, wave-cut cliffs, and terraces are found at varying distances inland. Door, Racine, and Kenosha Counties possess the best preserved of the ancient shorelines of the glacial predecessors of Lake Michigan.
The Eastern Ridges and Lowlands is a glaciated plain, flanked by northeast-southwest running cuestas of Lower Magnesian and Black River limestone on the west, and by a broader and higher parallel escarpment of Niagara limestone on the cast. In contrast to the cuestas of the Western Upland the escarpments are generally of lower altitude and are simpler in outline. Between the two cuesta flaakings a lowland, underlain by Galena-Black River limestone and St. Peter sandstone, provides the level topography and fertile soil which make this province the foremost agricultural portion of the State.
For a distance of some ninety miles in the upper part of this Green Bay-Lake Winnebago-Rock River Lowland the topography is that of a smooth plain, made so by evenly spread glacial lake deposits. From here south topography is progressively more irregular until in the southern lowland the area is marked by a glacially made landscape of modified hills, moraine and drumlin mounds, many small streams, and lakes. A great kettle moraine, an irregular mass resulting from glacial accumulation between two lobes of the ice sheets, and marked by deep hollows and knobs, is an important topographical feature of the area from Kewaunee County south to Walworth County.
The principal lakes of the Lowland are the Oconomowoc group and the Lake Geneva group in the south, a large group north of the Oconomowoc group, the Madison chain, and Lake Winnebago; the chief river systems are the Rock and the Fox of Illinois in the south and the Fox of Wisconsin in the north. A series of rapids in the northern Fox River provides the most valued water power in the State. Important manufacturing cities have developed at the sites of the rapids, and these, with Fond du Lac, Oshkosh, Madison, and the cities of the Lake Michigan shore, make the Eastern Ridges and Lowlands region the most highly populated and industrialized of the five geographic provinces. The lake regions, Terry Andrae, Peninsula, and Potawatomi State Parks, and the coastal islands and mainland of Door County are notable for their scenery.
Between the Western Uplands and the Eastern Ridges and Lowlands is the great crescent-shaped Central Plain. With the exception of a small area in the northwest portion which is floored by Keeweenawan lavas, all of the area is immediately underlain by Cambrian sandstone. Elevations vary from 685 feet above sea level (at Ellis Junction) in the eastern end of the plain to 1,242 feet at the western end.
Within the 13,000 square miles of the crescent are both driftless and glaciated areas. The unglaciated Camp Douglas country extending from Wisconsin Dells through Mauston and Camp Douglas to Tomah, and from Camp Douglas through Wyeville and Black River Falls to Merrillan and Humbird, a flat expanse of sandy, arid-looking landscape broken frequently by isolated buttes and mesas, is typical of Central Plain "driftless" country. Roche à Cris, standing 225 feet above the plain, and Friendship Mound, even higher, are well known among scores of castellated ridges and mounds.
Though the Camp Douglas country was never overridden by the glaciers, the water from the melting ice sheets covered the region with lake deposits -- sand, gravel, and clay. Some of the Camp Douglas country is within a much larger area, which was once the basin for glacial Lake Wisconsin, and much of the Camp Douglas sand is sand of that lake bottom.
The glaciated landscape of the Central Plain is one of low, rounded hills and moraines, with occasional castellated hills, called nunataks, which were surrounded by the ice during the glacial period but never overridden by it.
Three-quarters of a million acres of swampland lie within the Central Plain. One great swamp covers an area of 30,000 acres between Wisconsin Rapids, Camp Douglas, and Black River Falls.
Lakes are few within the crescent. Some lie in the northwestern part of the section and a few others in the east within Waushara County. Green Lake in Green Lake County is deepest of all inland Wisconsin lakes; Lakes Shawano and Poygan, associated with the Wolf River, are among the largest lakes of the Central Plain. Major rivers are the Wisconsin, Wolf, Fox, Black, Chippewa, and St. Croix. The Wisconsin and the St. Croix rivers have both cut deep gorges, the beautiful Dells of the Wisconsin at Wisconsin Dells and the Dalles of the St. Croix at Interstate Park near St. Croix Falls. Rapids on the Chippewa River provide water power for the furniture factories and paper mills at Eau Claire.
With the exception of a relatively small area touching on Lake Superior, all of Wisconsin outside the belted plain is Northern or Lake Superior Highland. This plain, covering 15,000 square miles, shield-shaped and gently arched -- with elevations ranging between 700 and 1,700 feet -- is part of a great upland area which reaches beyond Wisconsin to Canada, Labrador, and Hudson Bay. Its moderate topography and underlying pre-Cambrian rock are evidence of the Wisconsin which was once all lofty mountains. Now only in the Northern Highland and a few other places are the early gneisses, quartzites, granites, schists, and lavas exposed.
Certain ridges and monadnocks are remnants of the early landscape. These more resistant metamorphic rocks stood above the ancient plain much as they do now. The eighty-mile long Penokee-Gogebic Range in the northern part of Ashland and Iron Counties is an outstanding example of a pre-Cambrian ridge. The quartzite Barron Hills of Barron County, the Flambeau Ridge of Chippewa, and quartzite Rib Mountain near Wausau are prominent. The latter, rising 1,940 feet above sea level, is the highest known outcrop in the State. The mountain summit has been designated a State Park.
Most of the Northern Highland was glaciated, but a small area near Wausau, Stevens Point, and Wisconsin Rapids escaped the ice. Some hundreds of square miles in Marathon, Wood, Clark, Taylor, Lincoln, and Langlade Counties are within an old drift area which was abandoned by the ice earlier than other parts of the highland. Here the lakes and swamps have practically all been drained and filled, the landscape shows great erosion, and the pre-Cambrian rock is almost everywhere very near the surface.
Areas of younger glaciation have abundant lakes and swamps and many moraines and drumlins; they are covered with a great thickness of drift. Lakes of the glaciated Northern Highland fall into two groups those of northwestern Wisconsin, of which Lakes Court Oreilles, Upper St. Croix, Chetek, and Namekagon are probably best known, and those of the extreme northern part of the State in Vilas, Oneida, and adjacent counties. The latter, the Highland Lakes group, are numbered in the hundreds. Most of the lakes lie in holes, called kettles, that were left by the melting of ice blocks buried in the drift.
Principal rivers of the Northern Highland are the St. Croix, Chippewa, Menominee, Wolf, and Wisconsin. All of these rivers have rapids and waterfalls and are a source of water power. Extensive marshes, numerous boulders, and frequent areas of poor sandy soil that are found in the glaciated parts of the Northern Highland, combined with a short growing season, make much of this region better suited to forestry and recreation than to farming.
The Lake Superior Lowland, fifth and last of the geographic provinces, is a comparatively small region of 1,250 square miles -- all within Douglas, Bayfield, and Ashland Counties in the northwest corner of the State. It is essentially a plain, with altitudes ranging between 600 and 1,000 feet above sea level.
Presumably this area was one part of a great pre-Cambrian peneplain which included the area now occupied by Lake Superior, the Northern Highland, and areas extending northwest into Minnesota and northeast into Canada. Unlike the hard bedrock of most of the peneplain, a relatively small part of the area was of weak sandstone and shale. In a period of uplift the rock weathered and was worn away to such an extent that the area became a lowland. Eventually the continental ice sheets covered the lowland, scoured its surface in some places, and left deposits in others. The water from the melting glaciers formed a mammoth lake whose waters spread and retreated, becoming finally the present Lake Superior.
The Lake Superior Lowland is covered by the deposits made when the lake extended farther inland; abandoned beaches and shorelines are frequently evident. The sand and clay soil, largely compounded of Lake Superior deposit, makes the region better adapted for grazing and for hay production than for grain and general agriculture. Glacial drift is thick in certain parts of the lowland and contains some native copper.
For a considerable distance inland from Lake Superior the postglacial streams have cut deeply into the plain, and here the landscape is one of ravines and hills.
The most prominent relief feature of the Lowland is the escarpment which extends southwest to northeast from the Wisconsin-Minnesota line to the Apostle Islands and marks the boundary between Superior Lowland and Northern Highland. A companion escarpment edges a lowland of Minnesota. The two indicate the abutment of weak sandstone against the hard lavas and other older rocks of the Northern Highland. The Superior escarpment appears at Ashland as a low sloping wall and, south of the city of Superior, as the South or Douglas "Copper" Range.
As the St. Louis, Nemadji, Brule, Bad, and Montreal rivers descend over the Superior escarpment to the lake, they have developed cataracts which are among the steepest in the State. The Copper Falls of the Bad River and the falls at the juncture of Tylers Fork and the Bad River may be seen at Copper Falls State Park near Mellen. Little Falls and Manitou Falls on the Black River (tributary to the Nemadji) are in Pattison State Park south of Superior. Manitou Falls, one hundred and sixty feet, is the highest cataract in Wisconsin.