Back when the continents were all still smushed together into a massive glob, as the first plants ever were taking root on land, when the limestone that underlies Ottawa was still forming, submerged beneath the shallow eastern shore of a massive sea that covered most of what is now North America, some of the most primitive cyanobacteria organisms on Earth were growing into thin sheets of biofilm which slowly churned out a mucus that mixed with sediment and gelled into hard-as-rock patterns.

Ottawa's approximate location 450-million years ago, underwater near the shore of an ancient sea.
Ottawa’s approximate location 450-million years ago, underwater near the shore of an ancient sea. Courtesy

400 million years later, after Canada drifted northward from the equator to its deceptively stable resting place at the footsteps of the North Pole, after many seas have flooded and retreated across what is now the Ottawa Valley, after mountain ranges had risen and been weathered down, after the entire evolution of the human species and the rise and fall of every civilization we’ve had… those bacterial poo rocks patterns are still with us – a fully textured display of our planet’s history lying along the banks of the Ottawa River for all to wonder upon.

Picture of stromatolites near the Champlain Bridge on the Ottawa River. Photo from

The field of stromatolites, as the fossil remains of these bacteria are known, are found just beside the Champlain bridge on the Quebec side of the Ottawa River, revealed after thousands of years of erosion. These stromatolite remnants are over 450 million years old. The larger domes are laid out in parallel north-south lines which represents control of their growth by tides. The smaller stromatolites show a distinct east-west elongation, and this together with associated ripple marks, suggests the flow of longshore currents in a shallow-water warm saline environment.

So, why am i waxing nostalgic about the time before dinosaurs? Because the stromatolites are usually submerged under the running water of the Ottawa River, except sometimes when the water is especially low… like right now!

You can park at the Champlain parking lot, just off of Boulevard de Lucerne, and walk down beside the water. You’ll be treated to a sight a half a billion years in the making, and in the presence of your ancestors 🙂

Take a listen to retired Professor Allan Donaldson professor from Carleton University’s earth sciences department talk about these cool formations:

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