The Year of the Niagara Escarpment

By Joanne Kluessendorf

The Wisconsin State Legislature has proclaimed 2010 the “Year of the Niagara Escarpment” and May the “Month of the Niagara Escarpment.” From the steamboat excursions in the late 1800s to today’s cyclists and hikers, people have been drawn to the Niagara Escarpment’s rocky ledge for more than 150 years as a place for recreation and relaxation. Although rock seems commonplace and indestructible, the area is a unique, fragile feature, providing us with wildlife, water, resources, recreation and respite.


Shortly after departing Menasha by sailboat, their destination came into view. They were heading for the limestone ledge on the east side of Lake Winnebago. Reaching the shore, they gathered up their tools, and began their ascent to the top of the ledge. Tormented by mosquitoes, they made their way to the top of the 200-foot-high cliff.

The climb was difficult, especially the last 40 or 50 feet, which was nearly perpendicular. Reaching the summit “fully paid for their labor with a magnificent view of the lake and surrounding country.”

The man who planned that trip in the summer of 1850 was Increase Lapham, Wisconsin’s first scientist. He came to map the animal-shaped earthen mounds, which Native Americans had built on the ledge-top centuries before. Placing such sacred symbols there, the mound builders must have considered the ledge a very special place.Escarpment Pullout

It is unlikely the rest of the group knew how special it actually was. Lapham, on the other hand, had a hunch. A native of New York, he had worked as an engineer on the Erie Canal before coming to Wisconsin. As soon as he saw the “ledge of limestone” in Wisconsin, he compared it to “the banks of the Niagara below the great falls, or the mountain ridge as is seen in western New York and Canada.”

He noted that, as they were “composed of rocks of the same geological age, the resemblance is not to be wondered at.”


Lapham was the first to realize that the ledge along Lake Winnebago is part of the prominent ridge of rock now called the Niagara Escarpment.Escarpment Map

It is one of the largest natural features in North America and forms the ancient “backbone” of the continent.

Named for Niagara Falls, which cascades over its edge, the escarpment stretches nearly 1,000 miles in an arc across the Great Lakes from western New York State into southern Ontario, Canada, south through the Upper Peninsula of Michigan, and into Wisconsin. At more than 1,000 feet high, the escarpment rises to its maximum height in Ontario.


An escarpment is a scientific word for a steep cliff face. But not just any cliff face. It’s one at the edge of a cuesta, which is a sloping ridge made of slightly tilted layers of rock. The steep cliff forms when soft rock, like shale, erodes away beneath hard, resistant rock like limestone, which then breaks off to create the flat cliff face.Escarpment Cliff

The Niagara Cuesta formed when movements in the Earth’s crust caused rocks to sag into a bowl-like depression where Michigan is now. The exposed, up-tilted, outer edge of this “bowl” formed the Niagara Escarpment.

In Wisconsin, it faces west, in Ontario it faces north or east, and in New York it faces north.
It is not part of a giant reef, as it is sometimes described. Although rocks of the same age occur in adjacent parts of the U.S. and Canada, they are not part of the exposed cliff.

What is now solid rock in the escarpment was once soft mud on the seafloor. During the Ordovician and Silurian periods of Earth’s history, about 450 to 430 million years ago, shallow seas covered much of North America (geologists and archaeologists list the oldest date first because it came first).

Wisconsin was located about 20 degrees south of the equator because of plate tectonics, so the climate was tropical. Over time, the mud turned to rock, was exposed at the surface, weathered and eroded. The harder Silurian dolomite (magnesium-rich limestone) formed the steep cliff face above the crumbly Ordovician shale.

You can see this relationship as you drive the road to the ledge-top at High Cliff State Park in Calumet County.


In Wisconsin, the escarpment is known commonly as “the ledge” or “the bluff.” It runs discontinuously for about 250 miles through the eastern part of the state from Rock Island at the tip of Door County, through Brown, Kewaunee, Manitowoc, Calumet, Fond du Lac, Dodge and Waukesha counties.

At 250 feet tall, it is highest along the western edge of the Door Peninsula. It reaches its lowest point in Waukesha County, where it disappears near Scuppernong Marsh.

During the last ice age, the rock ridge caused the vast glacier moving south from Canada to detour, splitting it into two lobes. One lobe scoured out Lake Michigan and the other carved out Green Bay.

EscarpmentThe area helped to create some of our most famous scenery and gave us some things that aren’t so visible, such as caves. These were created about 10,000 years ago when water from the melting glacier surged into fractures in the ledge, enlarging them into caverns.

You can explore the inside of the escarpment at Ledge View Nature Center in Calumet County or Cherney Maribel Caves County Park in Manitowoc County.

Today, cold air circulates through fractures in the rock, creating microclimates that support a number of unique animals and plants. Among these living treasures are tiny land snails that are remnants of the last ice age and some very ancient trees. The oldest red cedar tree in the world grows here.

Springs flow from the escarpment and it is important for groundwater recharge, however, drinking water can be easily contaminated. The overlying soil is so thin that pollutants cannot be filtered out.

The only significant waterfalls are the Wequiock Falls and Fonferek Falls found in Brown County.


Cultural remains of Wisconsin’s first settlers can also be found on the Escarpment.

About 1,500 years ago, Native Americans began to build earthen, effigy mounds in the form of animal and geometric shapes. Many of the mounds held burials, but others may have marked clan territories or ceremonial sites. Hundreds, if not thousands, of these mounds were built on top of the escarpment, especially along the east side of Lake Winnebago, suggesting they considered it sacred.

More than 90 percent of the mounds around Wisconsin have been destroyed, but some “panther” mounds have been preserved on the escarpment at High Cliff. And, unlike Lapham, you don’t have to climb the cliff to see them!

When European settlers arrived in Wisconsin in the mid-1800s, they found economic uses for the area. The layered rocks in some places along the ledge provided fine stone for buildings and foundations.

Lime Kiln RuinsWhen burned in kilns, some of the dolomite made excellent lime, which was used mostly for mortar.

Remnants of limekilns, similar to those at High Cliff, are scattered along the entire escarpment and quarrying is still a vital industry in the area.

Iron ore was mined at Neda in Dodge County, and furnaces in Mayville turned out cast iron products for decades. One of the abandoned mines is an important bat hibernaculum.

The settlers also discovered that the limy soil on top of the escarpment was perfect for raising crops and dairy cows.

Today, vineyards are sprouting up, especially in Kewaunee, Brown and Door counties, and this area is being designated as an American Viticultural Area.


Perhaps one of the most significant aspects of the escarpment is its singular beauty found on the stark white bluffs of Door County, the craggy Oakfield Ledge in Fond du Lac County, and the brooding cliff face at Ledge Park in Dodge County. Wherever the escarpment occurs, it imparts a distinctive character to the local landscape; a sense of place.

It encourages reflection, provides respite and inspires with its primitive beauty. And just like explorer Increase Lapham, we marvel at the spectacular views it offers. We need to protect and preserve it, so future generations can enjoy its many gifts.

Whether you call it “the ledge,” “the bluff,” or “the escarpment,” let’s celebrate our piece of the Niagara Escarpment in 2010 and every year to come! Love the Ledge!



 Joanne Kluessendorf is founding director of the Weis Earth Science Museum at the University of Wisconsin-Fox Valley in Menasha. A Milwaukee native, she holds a doctorate in geology from the University of Illinois. Prior to returning to her beloved Wisconsin, Joanne was a curator at the University of Illinois Museum of Natural History, wrote National Historic Landmark nominations for the National Park Service & consulted with government & industry on geological issues. She is a fellow of the Wisconsin Academy of Sciences, Arts & Letters and the Geological Society of America, and has received numerous honors including the American Geological Institute International Award for Outstanding Contributions to the Understanding of Geoscience, and the Richardson Award for Outreach from the Mid-America Paleontological Society. She lives in Appleton, just a ten minute drive from the Ledge.

Photos courtesy of Joanne Kluessendorf.

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Escarpment GrapesSure to excite wine enthusiasts in the area, an area touched by the escarpment in northeast Wisconsin is vying for American Viticultural Area (AVA) certification. The AVA recognizes grape-growing regions and has taken Steve De Baker, owner of Trout Springs Winery in Greenleaf, nearly four years to develop.

All AVA information goes through the Alcohol and Tobacco Tax & Trade Bureau (TTB) and requirements include evidence that climate, soil and physical features are distinctive. With the help of Eric Fowle at the East Central Regional Planning Commission, De Baker sifted through 125 years of Wisconsin Climatological data to prove that his winery is on average 7–20 degrees warmer than the rest of the state. That translates into a longer growing season when grapes have more hang-time in the vineyard to ripen.

“Different mitigating factors, such as soil, geology, marine influence, wind and hydrology, make this region of the world very unique for a viticultural region,” says De Baker. “Who could have known that what happened over a million years ago would celebrate the fruits of our labor and give back for all to enjoy this special place we call the Wisconsin ‘ledge!’”

Acceptance of this new AVA certification will allow his winery to put year dates and ‘estate grown’ on the wine bottles and stimulate more agri-tourism in the region.

When it comes to the grape-growing culture, learn what makes Wisconsin special. On June 10, the Neville Public Museum is hosting the “Northeastern Wisconsin Wine Roundtable & Reception,” giving participants a chance to sample locally-crafted wines with appropriate food pairings. A handful of our area’s expert growers will be in attendance to answer your questions about wine and the business. On June 19, the museum will entertain at “The Ledge: Uncorked,” an evening of wine, jazz & awareness. “This is an event to bring all entities together in celebration of the escarpment,” adds De Baker. Visit www.nevillepublicmuseum.org for more information!

— FC