Rib Mountain in Marathon County, Wisconsin — The American Midwest (Great Lakes)
Ancient Ripples
Photographed by Keith L, June 8, 2008
1. Ancient Ripples Marker
Over time, the sand grains cemented and transformed into sandstone, and eventually, with more heat and pressure, into quartzite, a very hard rock. This process preserved these ripple marks.
For the next several hundred years, extensive weathering and erosion reduced the surrounding region to a flat "peneplain." However, Rib Mountain, with its hard, resistant quartzite, projected high above this surface.
Then, about 600 million years ago, expanding oceans covered Wisconsin, depositing thousands of feet of sediment. Slowly, these layers of sediment wore away, once again revealing Rib Mountain and its ancient ripple marks.
[caption] Pictured above are algal stromatolites composed of blue-green algae, bacteria, and silt on the bottom of the Pre-Cambrian Sea. They are believed to be the first life-forms to colonize the earth.
Erected by the Wausau Area Jaycees and the Friends of Rib
this page online
Topics. This historical marker is listed in this topic list: Natural Features.
Location. 44° 55.236′ N, 89° 41.664′ W. Marker is in Rib Mountain, Wisconsin, in Marathon County. It can be reached from Park Road west of County Highway N. Marker is by the Queen's Chair in Rib Mountain State Park (fee area). Touch for map. Marker is at or near this postal address: 4200 Park Road, Wausau WI 54401, United States of America. Touch for directions.
Regionally, this marker is in Northern Wisconsin. It is also in the American Midwest and in the Corn Belt. Globally, it is in North America, the Great North Woods, the Western Hemisphere, the Western World, and the Anglosphere. Historically, it finds itself in what was once the territory of the Mississippian Culture and also the Northwest Territory.
Other nearby markers. At least 8 other markers are within 4 miles of this marker, measured as the crow flies: To Charles E. Parker (a few steps from this marker); Rib Mountain State Park (a few steps from this marker); Skiing Rib Mountain (within shouting distance of this marker);
Photographed by Keith L, June 8, 2008
2. Ancient Ripples Marker
Another marker is no longer nearby. Rib Mountain State Park (was within shouting distance of this marker but has been confirmed missing).
Photographed by Keith L, June 8, 2008
3. Ancient Ripples
Photographed by Keith L, June 8, 2008
4. Queen's Chair
Photographed by Susan Van Den Bosch, October 30, 2025
5. Ancient Ripples Marker
Credits. This page was last revised on September 4, 2026. It was originally submitted on February 21, 2009, by Keith L of Wisconsin Rapids, Wisconsin. This page has been viewed 1,828 times since then and 53 times this year. Photos: 1, 2, 3, 4. submitted on February 21, 2009, by Keith L of Wisconsin Rapids, Wisconsin. 5. submitted on October 30, 2025, by Susan Van Den Bosch of Almond, Wisconsin. • Kevin W. was the editor who published this page.
