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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

August 2000

A rocky outcrop of the Niagara Escarpment overlooking Lake Winnebago. © Jean B. Meyer
A rocky outcrop of the Niagara Escarpment overlooking Lake Winnebago.

© Jean B. Meyer

Exploring Wisconsin's great cliff

The Niagara Escarpment forms cliffs, caverns and drama as it arches through eastern Wisconsin.

Doug McLean

Picture yourself on a high cliff, enjoying a panoramic westward view over the waters of Green Bay, Lake Winnebago or Horicon Marsh. That cliff, called the Niagara Escarpment, is a geologic formation that runs hundreds of miles through our state and beyond, forming a great circle all the way to Niagara Falls at the New York-Canada border.

Along the escarpment you can explore crevasses, caves, and rockfalls, see beautiful rock formations, or search for fossils, Indian artifacts, rare plants and animals. You can hunt deer along this cliff, sometimes seeing them below you or above you; fish the deep waters near its wall; or hike paths that climb from the cool springs at the bottom, through huge tumbled blocks of limestone, to the smooth high ground above.

The Ledge, as this escarpment is often called, is where I do many of these things. From my home, I overlook more than 20 miles of the Ledge winding north toward Fond du Lac and up the east shore of Lake Winnebago. Let me point out many of its secrets that you may enjoy too.

The layer supporting the Ledge

The Niagara Escarpment is a 40- to 100-foot cliff that passes through the eastern third of our state, continues north of several of the Great Lakes, sometimes under water, into Canada, and down to Niagara Falls. From there it enters the Appalachians, where it is crumpled and folded, then goes south into Pennsylvania, Ohio, Indiana, and back through Illinois into Wisconsin.

This cliff is the edge of a vast sedimentary rock layer, one of several in the layer cake of sediments that formed on the bottom of ancient seas. This layer is like a giant saucer, with its western edge in Wisconsin, and its eastern edge at Niagara Falls. Some layers were composed of erodible material, others of limey material from the bodies of marine life. The Ledge is a hard limestone layer called Niagara dolomite, and it contains fossils of the simple life forms existing at that time. The Ledge is 400 million years old. The Rockies are only 70 million, and the Appalachians 300 million.

When the seas receded, the edges of the layers were exposed and most of them weathered into obscurity. The Niagara layer has retained its cliff edge because the layer beneath it is soft shale, which erodes quickly, leaving the dolomite overhanging. The dolomite eventually breaks off again and again, forming a new cliff face each time – just as it has at Niagara Falls, where the process is so dramatic that it can be measured in miles per century.

One other thing is responsible for the look of the Ledge: Ice. Mile-thick moving ice of successive glaciers obliterated the cliffs in some places and created huge fissures and crevasses in others. Although the cliff would be higher and sharper today without the glacial bulldozing, the crevasses and caves are left as great places to explore.

Much of the Ledge is wooded. There is too much fallen rock at its base, too little soil on top, for farming. There is often water at the base in the forms of springs, marshes, and lakes. Springs pop up at the base because dolomite, though hard, is fractured, filtering groundwater down until it comes to the underlying layer of shale, which is almost impermeable; as a result, the water is forced out in springs.

Life on the Ledge

Deer love this environment, and I like to bow hunt them here. Of the handful I have taken, all but one were taken here. A few years ago, a wounded deer led us on a daylong winter trek up and down the Ledge before we got it. On another occasion, I found my deer lying within inches of falling over the cliff. My stand that day was in a tree that leaned over the Ledge, so that, if I spotted a deer down below heading for one of the trails, I might "head 'em off at the pass."

Foxes, coyotes, rabbits, and other small animals den in the rocks. Wild turkeys, recently released on the Ledge here in Fond du Lac County, frequent the sheltering cliff. I walked along the top edge of the cliff last December and was startled from time to time as one turkey after another exploded from the rocks and yew bushes directly below me. Goose and duck hunters sometimes place blinds at the top of the Ledge, hoping for closer shots.

Unusual plants, birds and animals find the Ledge's microclimate congenial. The only grouse I ever saw in this county was seen here, as well as the only pileated woodpecker. The springs, the coolness of cliff and crevasse (snow has remained as late as August in some crevasses), and the shelter of rockfalls have combined to make an atypical environment. Walking fern, which puts down rhizomes from its leaf tips to form new roots, ground-hugging American yew bushes, and plenty of limestone-loving red cedar, which often clings to the cliff face with roots squeezed into fissures, can all be found on the Ledge. A friend showed me one 14-inch diameter section of red cedar from the cliff face that had 259 growth rings.

When I was a teacher, my imaginative students reported seeing all kinds of things on the Ledge: Rattlesnakes, cougars, bears, a wild man. The only one that was verified was the wild man – and he wasn't very wild; just fed up with society.

The same kids did bring proof of other things found on the Ledge: Fossils, crystals of calcite, dolomite, and garnet; and, best of all, artifacts. One boy climbed down into a crevasse, then into a narrow, roofed fissure. Inside, on a natural rock shelf, he found a three-inch spear point. In a narrow passageway among the crevasses, I found my own favorite point one day when I was out with my own bow and arrows. Near Mayville there is a cave where Indian rock paintings were found, and old-timers there spoke of Indian trails along the Ledge.

Artifact hunters do not hunt among the rocks so much as on the land that slopes down from the Ledge toward the marshes and lakes. This space can be as much as a half-mile wide and experienced hunters will search there on old shorelines, now high and dry. Here is where the most ancient native Americans would have left their artifacts – and a few 10,000-year old points have been found, points in use when woolly mammoths and early men followed the retreating glaciers.

Fossil hunters find cephalopods, brachiopods, chrinoids, various corals, and other fossils, principally in quarries. When the soil is stripped away, the top surface of the dolomite will also reveal glacial scratches and glacial polish as smooth as a table top, from the abrasive rock "flour" carried by the ice. I had a bit of this polished dolomite made into a belt buckle.

Following the Ledge

To hike on the Ledge, visit the state, county, and township parks located along the Ledge or ask private landowners for permission to cross their property. The longest hike I know of was one taken by two young men along 400 miles of the Ledge, where it comes down from Canada toward the Falls. To explore by car, go to Peninsula State Park and take either Shore Road along the base of Skyline Road on the top with its many overlooks and a tower; or drive out in the country and follow the escarpment along highways and back roads. Keeping it in sight will sometimes be a challenge, especially in southern Wisconsin. Usually, it appears as an elevated tree-covered line, with only a little rock showing in summer, except in the road cuts.

In some places the glaciers have obscured the Niagara Escarpment; in others, rivers have cut through it (Sturgeon Bay), and erosion has formed bays in it. The west shore of Door County, facing Green Bay, is the Niagara Escarpment, where you can see wave-cut terraces from ancient high water levels at the end of the Ice Age.

Wave-cut terraces on the Door County shoreline. © Deborah Proctor
Wave-cut terraces on the Door County shoreline, where the escarpment's dolomite slopes gently into Lake Michigan.

© Deborah Proctor

Have you ever noticed that, to get in or out of the villages along this shore, you must drive down or up steep roads? You are descending or climbing the Niagara Escarpment. On the east shore of Door County, the dolomite slopes gently into Lake Michigan, so that you can sometimes wade out into the lake a good distance. Though many people drive up and down the escarpment daily without realizing it, I remember boring my kids every time we drove over it by saying, "Here we go, over the Falls!"

While it may be easy for us to drive the Ledge, early settlers found it a barrier to travel. Near my home, a steep township road switches back down the Ledge, and it has a name – the Breakneck. There is another in Dodge County, and near Byron Marsh, far from any roads, I discovered a very old switchback, its stone wall crumbling, its surface choked with growing trees. It would not have been noticeable, except that winter snow outlined the man-made wall.

Many settlers who came here were not surprised to find cliffs. Half a dozen villages within a small radius in Fond du Lac and Dodge counties have the same names as a half dozen villages in New York State, just east of Niagara Falls. Westward-moving settlers brought their hometown names with them. The coincidence is that both localities are situated on the Niagara Escarpment. The question is, did the settlers know that they had moved to the same geologic formation, or did they just think that the new spot looked like their former home?

When this land was settled, economic uses were found for the Niagara dolomite, and the stone is still important today. Dolomite can be transformed into lime for farm and industrial use, or it can be crushed for road construction. Dolomite is used as building stone. Some is cut at right angles to its original horizontal position, producing a fresh look. Some is pried apart at its horizontal seams, giving a natural look. Most expensive of all is naturally weathered dolomite. Limestone construction can be seen in many old and new buildings. In my 100-year-old remodeled home there is an old basement stairs that now leads to nowhere, beautifully built of hand-hewn slabs of dolomite.

In early times, wells in dolomite produced good-tasting hard water. But fractures in the rock can allow surface water to enter wells, carrying pollutants. My first two wells had this problem. My third 540-foot well is cased through the dolomite and, from a layer of sandstone, produces safe, soft, iron-rich water. Back in prohibition times, one local entrepreneur poured waste mash from his illegal still into an old well. Through the fractures the stuff entered another well a quarter mile away, giving the water a mild Jack Daniels flavor.

Over the centuries people of many cultures discovered the Niagara Escarpment. Why not discover it for yourself? Like the bored teen-ager that walked it with my wife and I, you may have your boredom relieved. While we walked along the top, this person climbed down to explore below. For the next hour, yelps of discovery echoed up to us as she discovered secret passageways and robbers' dens among stone battleships and castles. More cries came to us as she was startled by scurrying, flying creatures, just as they were startled by the human intrusion into their cool, shadowy world of rock canyons.

Perhaps as you walk and climb these cliffs, you, too, will meet at eye level a sleeping owl, a cecropia moth, a flying squirrel, and you may be halted by the beauty of exotic flowers and strange fungi. Possibly, there will be for you a snow-white arrowhead lying among the rocks, a little time capsule from the past, releasing to your imagination histories long buried in the decaying humus on which it lies. Or maybe you will only be able to explore the escarpment by car, to admire the ancient, mossy rocks, durable through so many millions of years, yet slowly crumbling, as do all things. Then let these rocks stretch in your imagination to the faraway place where Niagara's waters plunge over them. Go ahead, explore the Niagara Escarpment. It has been there a long time, waiting for you.

Doug McLean writes from Brownsville, Wis.