Wisconsin’s geologic history is imprinted on the land. Geologic formations such as Devil's Lake, the Baraboo Hills and Pier Natural Bridge Park are remnants of a history that extends back millions of years.
John Muir, the Scottish-born but Wisconsin-raised naturalist and author, known as the “Father of the National Parks,” once wrote, “Glaciers … crushed and ground and wore away the rocks in their march, making vast beds of soil, and at the same time developed and fashioned the landscapes into the delightful variety of hill and dale and lordly mountain that mortals call beauty.”
During the last 2.5 million years, ice sheets repeatedly gripped and shaped the earth. Wisconsin is one of the best places in the world to witness landforms created by continental glaciation. So much so that the last period of the Ice Age, which ended about 10,000 years ago, has even been given the name Wisconsin.
Most of the state was bulldozed by the repeated visits of these glaciers, some of which were more than one mile thick. The last of them was the Laurentian Ice Sheet, whose lobes stretched down over northern and eastern Wisconsin. The southwestern third of the state was left untouched, leaving unique formations and ancient landscapes such as Devil’s Lake, the Baraboo Hills, and Pier Natural Bridge Park. Many of Wisconsin’s native peoples consider this so-called “driftless” area uniquely powerful and important.
The natural bridge in Pier Natural Bridge Park in Richland County is one of the largest in Wisconsin at 20 feet wide and 10 feet high. It’s part of a half-mile long ridge of sandstone nearly 60 feet long where the West Branch of the Pine River meets the Main Branch. The confluence of these rivers forms a natural bridge. Used as a shelter by Native Americans for centuries, the bridge is also said to have been the sight of General Atkinson’s troop encampment on the night of July 29, 1832 during the Black Hawk War.
