Investigating Thunder Bay’s mysterious ring of rocks

Researchers think the puzzling rock formation might have been a sacred site — but a local Indigenous community is not so sure
By Charnel Anderson - Published on Aug 07, 2020
Anthropologist Scott Hamilton began studying the formation in late 2015. (Courtesy of Alex Bilyk)



THUNDER BAY — Made up of more than 1,000 rocks and about 35 metres in diameter, it normally lies beneath the surface of Boulevard Lake. What is the oval-shaped formation, and where did it come from? No one knows for sure, but anthropologist Scott Hamilton and a team of researchers in Thunder Bay have been sorting fact from fiction in an effort to unearth the true origins of this mysterious ring of rocks. 

“Some people speculate that it is really a rock pile leftover from the construction of the dam,” says Hamilton, a professor in the Department of Anthropology at Lakehead University  “Somebody said it was a prank. There was even one person suggesting that it was the foundation rocks that held down a 1930s tent-revival religious meeting.”

Hamilton and other researchers from Lakehead University have been studying the rocks for years. Over time, and thanks to fast-paced technological innovations, they’ve discovered some clues as to what purpose the puzzling rock formation might have served. 

The rock circle is “quite large,” Hamilton says, and composed of rocks of various sizes. Most are embedded in the muddy lakebed; some, he adds, are “large, angular pieces of rock that look like native stones from the Gunflint Formation” and would be “pretty difficult to move around.” However, the majority of the rocks, he explains, are “less than 10 or 14 inches across … rounded cobbles that look like stones that have been collected off a washed beach.” In his view, the formation was likely human-made.

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In the early 20th century, a hydroelectric dam was built on the Current River, creating the Boulevard Lake reservoir. This spring, the lake was drained in order to facilitate the rehabilitation of the century-old dam — which, according to Mike Vogrig, project engineer with the City of Thunder Bay, is no longer used as a source of electric power, but helps manage the lake’s water levels — giving Hamilton and others an unprecedented view of the rocks. 

Hamilton began studying the formation in late 2015, when low water levels in Boulevard Lake left it more exposed: he and his team took photos of the stone circle using consumer-grade drones and later used software to stitch the images together, creating a 3-D model. 

This year, Hamilton and his team did something similar, but with new drones and sensors. As Alex Bilyk, a sessional instructor in the Department of Natural Resources Management at Lakehead University and one of the researchers working with Hamilton, explains, they used two sensors: a high-resolution camera that uses the same electromagnetic spectrum as the human eye, and a lower-resolution, multi-spectral sensor that “captures far beyond what the human eye can see.” 

Researchers also employed a Terrestrial LiDAR scanner, which uses laser beams to measure distance. As Bilyk puts it, “It’s radar with light.” Bilyk says they’ve collected one-and-a-half billion data points on this particular set — they’ll be used to understand the stone circle’s orientation and its relation to other features, such as the old Current River water line. 

Based on the rock ring’s location on “a big open floodplain, immediately above a set of falls, on a flat terrace overlooking the river’s original course,” Hamilton says, the formation likely predates the construction of the dam. “Given the relatively recent settlement of Prince Arthur’s landing,” he explains, “it’s probably a post-1850, -1860 deal.” 

Before the dam’s construction, Hamilton says, the site would likely have been a “very attractive place” for an encampment, because of its proximity to the river, a seasonal fish-spawning ground, and the waterfall: “From my perspective, the most plausible explanation is that it’s somehow related to Indigenous occupation — and probably pre-settlement of Port Arthur.” 

The team studying the rocks — which includes graduate students from the Department of Anthropology and faculty in the Department of Natural Resources Management and the Centre for the Application of Resources Information Systems — have been working in collaboration with local First Nations communities, including Fort William First Nation. 

And it’s not so sure that the site is Indigenous in origin. 

As Hamilton points out, the ring isn’t a perfect circle, nor is it a complete circle. “The southwest quadrant … is open,” he says. “I’m not sure whether it’s because those rocks are buried in the muck in the reservoir bottom or whether there’s a gap that was deliberately left open.” The cardinal direction of the gap is significant, says Robert Pierre, economic development officer at Fort William First Nation, because, “traditionally, any of our structures that are of ceremonial significance have eastern-facing doors.” 

Pierre says that most community members in Fort William were not aware of the rock ring’s existence: out of a handful of Elders consulted, only one had known about it, and they believed it had been constructed post-contact. According to Pierre, Fort William First Nation believes the site might have been part of a stable used to park horse-drawn carts for visitors. 

So far, researchers have been careful to use only non-invasive research methods, so as to not disturb what Hamilton believes could be a potentially sacred site. While the research so far has been inconclusive, researchers are interested in the possibility of using ground-penetrating radar and taking soil samples, which may help determine when the rock formation was constructed. 

Will the mystery surrounding the 35-metre rock formation ever be definitely solved? “You mean a definitive, ‘Wow, we really know, and there’s no more curiosity’? No,” says Hamilton. “I think usually what happens is that people like me come up with their best guess, based on the information at hand at that time. And, like all science, subsequent work refines or refutes those initial interpretations.” 

This is one in a series of stories about issues affecting northwestern Ontario. It's brought to you in partnership with Confederation College of Applied Arts and Technology. Views and opinions expressed in this article are not necessarily those of the college.

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