The Ottawa River’s Hidden Geohistory

Explore the largest exposures of stromatolites in a North American city to learn more about the Ottawa River's incredible geological history.

Written by Joe Ryan

In New York State’s Lester Park a large assemblage
of stromatolites has been designated as a unique site with signage that lets people know what they are and how they got there. Stromatolites are layered sedimentary structures created by films of cyanobacteria trapping sediment together. This particular paleontological site dates back to the Early Paleozoic Era, about 500 million years ago. It is a big draw for fans of nature, including many geologists from around the world.

Being able to walk out across such interesting structures in rocks so old is incredible, but is it worth driving to New York for?

It might be, but you don’t have to cross the border to see stromatolites. You can find them right here in Gatineau on the shores of the Ottawa River, tucked away under the Champlain bridge. Throughout the late summer and into the fall you can (water level permitting) wander off the Voyageurs Pathway and walk right onto one of the largest exposures of stromatolites in a North American city.


You wouldn’t know it if you stumbled upon them though. There’s no signage explaining what stromatolites are, their geological significance or even mentioning that they are right beside this bike path. The absence of information made available to the public is tragic.

It means most who walk by aren’t aware that these strata were there before the Champlain Sea; of the important role stromatolites have played in biological evolution, or know that the joints (the sets of straight cracks) in the rocks are a natural phenomenon. What appears to the untrained eye to be human interference with the rock is actually nature’s own doing.

What’s worse is that uninformed visitors can accidentally engage in destructive practices, harming the valuable stromatolite formations without even realizing it. In the same way we respect rare animals by shooting with cameras and not guns, we should be respecting stromatolites by taking pictures home and not bits of rock.

Ottawa-Gatineau Geoheritage Project is one of the organizations seeking to gain recognition and appreciation of the National Capital Region’s (NCR) stromatolites. They have designed self-guided field trips for this and similar important geosites across the NCR. The trips allow you to see all the amazing natural geohistory that’s so close to your backyard. However, this information is only available to people who are seeking it out. The casual cyclist or walker misses it completely.

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Dr. Al Donaldson, retired professor of geology, Carleton University, and founder of Friends of Canadian Geoheritage believes that large parts of the NCR, including additional stromatolite occurrences, but also many additional sites offering strikingly different insights into the history of our planet, could collectively qualify as a United Nations Educational Science and Cultural Organization (UNESCO) Geopark. According to the UNESCO website, “A Global Geopark is a unified area with geological heritage of international significance.” Canada is known worldwide for it’s natural beauty, yet it only has one UNESCO Geopark.

Having parts of the NCR designated as a Geopark is a dream of Donaldson’s, but getting a site designated requires it to go through a rigorous application process. It would be worth it to try though, because the designation works in tandem with local, regional or national legislation to protect and celebrate geosites such as this one on the Ottawa River.

A designation of that scale could not only expand the NCR’s appeal as a tourist attraction, but also increase the protection our yet-to-be-designated Heritage River deserves. In the meantime, Donaldson would be happy having the National Capital Commission (NCC) install signage at the site. and beyond that, he would also like to see local groups interested in environmental protection, history, and science work more closely together and offer support to one another.

The stromatolite site on the shores of the Ottawa River is one of several that the Ottawa-Gatineau Geoheritage Project highlights each year during Geoheritage Day in October. On that day, geoscientists will be at eight sites in the region from 10 am to 3:30 pm, ready to answer questions about the specific natural feature they are highlighting.

4 responses to “The Ottawa River’s Hidden Geohistory”

  1. Well said. I am a member of Dr. Donaldson’s group, live close to the stromatolite exposure and visit it often. But, as you say, the public has never been informed.
    Any help convincing the NCC that this could be an educational experience for many tourists and locals alike would be a big help!

    • Hey Karen –
      I’m a fan of the Ottawa-Gatineau Geoheritage Project and, in my opinion, Geoheritage interpretation is an underdeveloped gem (pun intended) for locals, school groups and a segment of tourism alike. I understand dealing with the NCC can be complex, but wouldn’t developing and presenting a straw man proposal (proposed approach, budget, opportunities to tie into existing geoheritage/tourism activities/educational curriculum, and securing an interested sponsor or other funding options) directly achieve your goal? Without sounding like a prig, I find that a well considered business case is all the ‘convincing’ one often really needs. It makes getting to ‘yes’ a whole lot easier.
      Kindest, Andrea

  2. Hi Andrea,
    Thanks for your comment.
    One would think that your suggestion would be reasonable. It does not seem so, though, as the OGGP has tried for many years to have this site recognized, but with no results. As a small group of (mostly retired) earth scientists with little financial resources, it is nearly impossible to put together a considered proposal. If you know anyone who might want to help, just let me know

  3. Nisha says:

    I was so excited to discover the Ottawa Geoheritage Project while looking for interesting field trips for my Geography class. We are visiting the stromatolites tomorrow – hopefully they are not underwater!
    I am actually amazed that there is no signage to indicate this phenomenon. Even a little informative plaque would be enough to let people know to respect the area. It would be a start. Even Hogsback Falls (another site we are seeing tomorrow) has a sign about the geological history of the area and the rocks.
    Perhaps you could team with the Museum of Nature to do a geoheritage project? Just a thought.