Geology of the Eagle Heights Woods - 17 May 2024

We are grateful that Phil Fauble took the day off from his work as a hydrogeologist with the state’s Department of Natural Resources to lead this field trip.  Sarah Lundquist, the Program Coordinator for the First Nations Cultural Landscape Tour and her assistant, grad student Brenda Owen (Ho-Chunk) worked with our own Signe Holtz, to organize this trip for the group’s training during the week of May 13.   

The First Nations Cultural Landscape Tour is an award-winning, place-based, walking tour, led by students. Guests learn about the First Nations of Wisconsin and the 14,000+ years of human history along the shores of Lake Mendota in the area known as Teejop (Four Lakes) and Madison. Participants visit UW-Madison campus buildings, historical markers, and archaeological sites to discuss historic – and contemporary – relationships with First Nations.  

The weather was perfect – sunny and a comfortable temperature –- when we met in the Raymer’s Cove parking lot with the students. Omar Poler (Mole Lake Band of Lake Superior Chippewa), Indigenous education coordinator with the Office of the Provost and Annie Jones (Menominee), a professor with UW–Madison’s Division of Extension, who co-lead UW’s Native Nations Work Group e program also joined us.  Kane Funmaker (Ho-Chunk), who is succeeding Brenda in the graduate student role, also came for the tour. 

After introductions all around, Signe Holtz, Friends field trip coordinator, read a statement acknowledging the ancestral relationship of the Ho-Chunk to the Lakeshore Nature Preserve.  Phil has led geology field trips for the Natural Resources Foundation for more than 30 years, primarily at Devil’s Lake, and he had several tips for a successful tour that he shared with the unique group of attendees.  He brought his son Nicholas, a rising junior at UW-Stevens Point, to assist him with tree identification and ecology. 

 #1: Tell a story.  When the audience learns the overarching story, they can retain the specific details of this rock and that formation.  Phil’s story began with the origin of Earth 4.5 billion years ago and he brought it all the way to the present.   
 #2: Keep the group together.  That’s more important than hustling to get to every site, but leaving individuals behind. 

After we walked down the stairs to Raymer’s Cove Beach, Phil pointed out the exposed wall of (Cambrian period) sandstone in the Tunnel City Formation, ~500 million years old, initially created by deposits in a vast tropical sea.  Lake Mendota’s wave action erodes the relatively soft sandstone. Phil pointed out the layer above the sandstone, the St. Lawrence Formation.  This is a layer of dolomite (= limestone impregnated with magnesium), formed after the end of the Cambrian period during the 42 million years of the Ordovician period.  The dolomite layer is much harder, and more resistant to wave erosion.  The result is a shelf extending above and beyond the sandstone around most of Lake Mendota.  We subsequently walked on that dolomite shelf.   

But first, Phil took us up a gulley to show us the Jordan Formation, a layer of pure silica sand that lies above the St. Lawrence Formation. Like the Tunnel Formation’s sandstone and the St. Lawrence Formation’s dolomite, the Jordan Formation’s sand was deposited by ancient seas. The three Formations we walked on, namely the Tunnel City, the St. Lawrence and the Jordan, are shown in the lower right portion of this diagram of “Paleozoic Stratigraphy” from Clayton and Attig, 1997.  

From Raymer’s Cove, we walked easterly on the St. Lawrence Formation above the lakeshore in the Wally Bauman Woods and paused to look across Lake Mendota to Middleton before turning south and up to Lake Mendota Drive.

Phil led us across Lake Mendota Drive and into Eagle Heights Woods.  He noted the wildflowers in bloom and the overall improvement in the Woods. The map above shows the areas of restoration that have been funded by the Friends, who have provided more than $138,000 for the multiyear project.  At the top of the hill, he stopped to point out three large rocks. 

The gray, sparkly granite and the red rhyolite are both igneous rocks, formed from magma, while the gray-and-white-striped gneiss is metamorphic rock, formed by high temperatures and high pressures on earlier formations.  All three rocks are erratics, transported here by the most recent glaciation, less than 25,000 years ago.  Phil described how they would have tumbled down the leading edge of the glacier.  We also stopped to observe the nearby dolomite outcroppings exposed by erosion.

Three Native American mounds lie within a relatively small area at the top of the hill.  Their presence will provide opportunities for the First Nations Cultural Landscape Tour guides to educate their guests on the significance of Eagle Heights to the First Nations ancestors and inspire their guests to view the site and its history with reverence.  Omar Poler, who had attended a previous tour Phil Fauble gave, volunteered, “Following that tour, I saw the campus landscape in a new way, and for that I am especially grateful.”

We returned to Raymer’s Cove and repeatedly thanked Phil.  This summary barely touches the breadth and depth of his presentation.  For more information, see Prof. Dave Mickelson’s “Geology of Eagle Heights Woods” at http://www.friendslakeshorepreserve.com/geology1.html
 
Report by Doris Dubielzig