Ottawa Gatineau Geoheritage

The Ottawa-Gatineau Geoheritage Project promotes greater public knowledge and appreciation of the geology and related landscapes in and around Canada's National Capital Region

5. Westboro Beach

Stromatolites, orthocones and trace fossils fossils

Westboro Beach

Kitchissippi Lookout parking lot, off Ottawa River Parkway, Ottawa, Ont.

Stromatolites seen in cross-section, Westboro Beach.

Photo by Q. Gall.

Section of Gull River Formation limestone at Westboro Beach. Stromatolites can be found in the bushes at the top of the section

Photo by Q. Gall.

Stromatolites are biosedimentary structures built up during sedimentation by cyanobacteria and blue-green algae. Layers were built up as the cyanobacteria grew up through successive depositions of lime muds to create rounded, domed structures. At Westboro Beach, the bedrock shows vertical cross-sections through these fossils. The fossils here are lined up with those seen in plane view near the Québec side of the Champlain Bridge.