Wisconsin Historical Society Press
Press Release

“Hidden Thunder” Illuminates Ancient Rock Art History

The voices of "Hidden Thunder" work together to strip the graffiti, misconception and mystery off the Midwest sandstone pictographs.

By - Sep 21st, 2016 10:03 am
Hidden Thunder: Rock Art of the Upper Midwest

Hidden Thunder: Rock Art of the Upper Midwest

Etched into stone, rock art has remained for thousands of years as the lasting record of indigenous peoples around the world. Petroglyphs and pictographs, such as those at the World Heritage Site of Lascaux Cave in France, draw the curious and the scholarly alike to read the stories in stone that those who came before left behind. A new book by the Wisconsin Historical Society Press, Hidden Thunder: Rock Art of the Upper Midwest, opens one of the lesser-known chapters in the world’s rock art tale, bringing to readers North America’s most important rock art sites in the Upper Midwest.

With an aim to increase the understanding of rock art and encourage its preservation, watercolor artist Geri Schrab and archaeologist Robert “Ernie” Boszhardt use science and art to connect readers to rock art history and culture in a way that neither could do alone. Boszhardt takes a comparative, analytical approach to understanding the sites while Schrab expounds upon her experience at each place, offering her interpretations of the symbolic and sacred resonance of the art. Boszhardt’s analysis increases readers’ objective, historical understanding of the sites while Schrab creates an artistic re-imagining of the old art.

Viewpoints shared by members of the Menominee, Ho-Chunk, Ojibwe, and other Native nations offer additional insight on the historic and cultural significance of these sites. Together these myriad voices reveal layers of meaning and cultural context that emphasize why these fragile resources–often marred by graffiti and mishandling or damage from the elements–need to be preserved.

The voices of “Hidden Thunder” work together to strip the graffiti, misconception and mystery off the Midwest sandstone pictographs and tell the long-forgotten stories of the ancient people whose art remains.


Geri Schrab is an award-winning watercolor artist whose sole artistic focus is American Indian rock art sites. She has twenty years of experience visiting and painting rock art sites across North American and Australia, with an emphasis on Wisconsin and the greater Lake Superior region.

Previous publications are “Bridging Time,” a fine art book, and “Weaving the Past with the Present,” a coloring book of North American rock art sites. Her work can be found online at www.gerischrabstudio.com.

Robert “Ernie” Boszhardt is a professional archaeologist with more than forty years of experience, the vast majority in Wisconsin. He worked for the Mississippi Valley Archaeology Center at the University of Wisconsin-LaCrosse for nearly thirty years and is now an independent archaeologist and an honorary fellow at the University of Wisconsin-Madison.


“Hidden Thunder” captures our inherent curiosity and creativeness, human traits that have always left their imprint on the places we live, work, and worship. The images, visions, and fantastic works of art painted and carved by American Indians hundreds of years ago still carry power, foster intrigue, elicit spiritual and emotional responses, and create dreams for the future and visions of the past. Ernie Boszhardt and Geri Schrab take readers on an inspiring journey of discovery and enlightenment to these places of enduring value.
John Broihahn, Wisconsin State Archaeologist

The dry, academic jargon found in so many rock art studies has been abandoned for rich descriptions that retain scientific vigor but in words we can understand. Personal experiences and artistic insights are mixed with scientific observations to produce a balanced view of the art found in these often-sacred spaces. “Hidden Thunder” is an essential book that opens a new path for appreciating rock art and sets a standard for describing a complex subject.
Thor Conway, archaeologist, anthropologist, author of Native American Rock Art, History, & Culture

The powerful ancient drawings of canoes, stars, bows, arrows, mythical beasts, birds, and our four-legged brothers stand with great meaning to those who understand the symbolism, and it saddens me that many of the existing sites have been and are continually being vandalized. We are grateful for the work being done by Ernie and Geri to preserve in some way what our ancestors have left behind.
Joey Awonohopay, Director of Language and Culture for the Menominee Tribe of Wisconsin


Thursday, Oct. 20, 2016 — Hidden Thunder Book Launch — A Wisconsin Book Festival Event

7 p.m.

Location: Wisconsin Historical Museum, 30 N. Carroll Street, Madison, Wis.
Join archaeologist Robert “Ernie” Boszhardt and watercolor artist Geri Schrab as they team up to interpret the hidden history and heritage of some of the American Indian rock art found in the Upper Midwest as they did for their new Society Press book, “Hidden Thunder.” This special event is co-sponsored by the Wisconsin Historical Society, the Wisconsin Book Festival, the Wisconsin Humanities Council, and the Charles E. Brown chapter of the Wisconsin Archeological Society. A book signing will follow.

Saturday, Oct. 22, 2016 — Hidden Thunder Book Talk & Signing* with Geri Schrab
Time: 1-4 p.m.
Location: Effigy Mounds National Monument , Harper’s Ferry, Iowa.

Tuesday, Oct. 25, 2016 — Hidden Thunder Book Talk & Signing
Time: 6:30 p.m.
Location: Lawton Memorial Library (La Farge, Wis.).

Thursday, Dec. 1, 2016 — Hidden Thunder Book Talk & Signing
Time: 1:30 p.m.
Location: Soldiers Grove Public Library, Soldiers Grove, Wis.

Saturday, Dec. 3, 2016 — Hidden Thunder Book Signing* with Geri Schrab
Time: 10 a.m. – 2 p.m.
Location: Woodland Studios, 195 E. Main Street, Stoughton, Wis. This event is part of an exhibit of co-author Geri Schrab’s artwork Nov. 18 – Dec. 31, 2016.

Saturday, Dec. 10, 2016 — Hidden Thunder Book Talk & Signing
Time:1:30 p.m.
Location: Kenosha County Archaeological Society, Kenosha, Wis.
* (unless noted, both authors will be present at the event)

The Wisconsin Historical Society Press has been publishing the best of Wisconsin history and culture, as part of the Wisconsin Historical Society, since 1855

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