The St. Lawrence River Isn't Really a River. It's a Wound.

At Québec City you can watch a tide of more than four metres rise and fall in fresh water, hundreds of kilometres from the open sea. Downstream, a trench about 300 metres deep runs toward the Atlantic. In 1663 an earthquake sent whole hillsides sliding into the river. Twenty-eight clues from the Thousand Islands to Anticosti, counted down to the one thing every map leaves out: below Montréal, the St. Lawrence valley is a tear in North America's crust about 600 million years old. What's beneath YOUR town? Personalized 15-page report — the rock, the name, the vanished places, your town's oldest map → https://hiddenprovinces.com The Thousand Islands as the summits of billion-year-old hills, outside the rift. The Long Sault Rapids drowned in 1958 and the 69-metre staircase of Seaway locks. The Lachine Rapids that stopped Cartier and built Montréal. Green Great Lakes water and brown Ottawa water running side by side for 150 kilometres. The volcano myth of Mount Royal and the line of the Monteregian Hills. The 1732 Montréal earthquake. A fin whale skeleton in a field near Daveluyville. Lake Saint-Pierre and the last 31 centimetres of tide at Trois-Rivières. Ice canoes between Québec and Lévis. The narrows that named Québec and Cartier's false diamonds. Logan's Line, where the Appalachians were pushed onto the continent. Montmorency Falls pouring over a rift fault. The salt wedge off Île d'Orléans. The Charlevoix crater, 54 kilometres across, and the earthquakes of 1663, 1870 and 1925. The Charlevoix coast as a fault scarp. The Saguenay fjord, the Tadoussac upwelling and the belugas. The Laurentian Channel, the earthquakes under the estuary, the Empress of Ireland and Anticosti's record of the first mass extinction. All of it sits along the St. Lawrence rift system: a failed arm of the Iapetus Ocean that opened about 600 million years ago, stalled, moved again when the Atlantic opened, and is now being slowly squeezed, which is why Charlevoix still shakes. Sources include Natural Resources Canada / Earthquakes Canada (eastern Canada seismic zones; historical events of 1663, 1732 and 1925), the Geological Survey of Canada (Current Research 2001-D15; Map 2168A; Geoscape Montréal and Geoscape Québec), Fisheries and Oceans Canada (tide tables; beluga Science Advisory Report 2023/024), the Canada Water Agency, the St. Lawrence Action Plan, Parks Canada, the International Joint Commission, the Canadian Register of Historic Places, Library and Archives Canada, the Ministère de l'Environnement du Québec, the Commission de toponymie du Québec, the Ville de Québec, Sépaq, the Saguenay–St. Lawrence Marine Park, the Port of Trois-Rivières, the Canadian Encyclopedia, the Dictionary of Canadian Biography, UNESCO, the Earth Impact Database, Harington (2003), Pinet et al. (2011, Geoscience Canada), Baird et al. (2009, 2010), Tremblay et al. (2001, 2003), Ebel (2011) and Schmieder et al. (2019). Where sources disagree, on the island count, the age of the crater, the size of the 1663 earthquake, the length of the Laurentian Channel and the age of the rift, the narration gives both figures. Subscribe to The Hidden Provinces — beneath the map.