Discover Canada and Explore the Fossils and Geodiversity of the Bay of Quinte in Ontario
- Wayne Munday
- Oct 19
- 5 min read
Sip back and discover Canada and explore the fossils and geodiversity of the Bay of Quinte, along the northern shore of Lake Ontario near Belleville, Trenton and Prince Edward County. With a fossil record dating back to between 457 – 449 million years to the Caradoc Stage, the region’s limestone and dolostone bedrock preserves fossils from the Black River and Trenton groups, which record a thriving marine ecosystem long before dinosaurs existed. The Gull River and Bobcaygeon formations document nearshore to open-marine environments, while the overlying Lindsay, Verulam and Cobourg limestones reflect deeper continental shelf conditions teeming with brachiopods, trilobites, bryozoans, rugose corals, crinoid stems and occasional cephalopods. These carbonate rocks were later succeeded by the Simcoe and Lorraine groups, reflecting a shift to siliciclastic sedimentation during the Taconic Orogeny and marking the end of the Great American Carbonate Bank a Sauk megasequence. The advance and retreat of the Laurentide Ice Sheet during the Pleistocene further sculpted this landscape, exposing outcrops and making the fossils accessible at places like North Beach Provincial Park, Presqu’ile Provincial Park, Wellington Rotary Beach, and Zwick’s Centennial Park or maybe visit Quinte Museum of Natural History to discover this extraordinary environment.
The Bay of Quinte lies in south east Ontario tracing the narrow Z-shaped inlet along the northern shore of Lake Ontario. Stretching for about 100 Km, it is bordered by Prince Edward County to the south and the mainland cities of Belleville, Trenton and Deseronto to the north. This region is the traditional territory of the First Nation people of the Wendat, Mississauga, Anishinaabeg and Haudenosaunee which includes the Kenhtè:ke Kanyen’kehá:ka or Mohawks of the Bay of Quinte. The bay connects with Lake Ontario’s main basin at its eastern end near Carrying Place and links to the Trent River at its western end forming part of the scenic Trent–Severn Waterway a 386 Km canal system connecting Lake Ontario to Georgian Bay on Lake Huron. Conveniently located midway between Toronto and Kingston, the region is easily accessible via Highway 401 making it an inviting stop for travellers. Its landscape blends limestone bluffs, sheltered bays and forested shoreline parks. Beyond its renowned Ordovician fossil beds, the Bay of Quinte region is celebrated for its wetland birdlife, rolling vineyards and protected natural areas such as Presqu’ile Provincial Park and Sandbanks Provincial Park.
Beneath its scenic beaches and limestone outcrops of the Bay of Quinte lies an ancient seafloor sediments from the Middle to Upper Ordovician Period dating back over 450 million years. This was a time when this region was part of Laurentia and lay beneath the warm and tropical Iapetus Ocean near to the equator in the southern hemisphere.
The fossiliferous succession of limestone and dolostone in the Bay of Quinte region is made up of both the Middle to Late Ordovician Black River Group and Trenton Group deposited on an extensive carbonate shelf in a warm and shallow tropical sea between 457 and 449 million years ago during the Caradoc Stage. This successions tells a story of a thriving marine ecosystem long before land plants and dinosaurs first appeared. The older Black River Group is underlying the younger Trenton Group.
Interestingly, the Caradoc Stage, the fifth of the six subdivisions of the Ordovician Period, was named by Sir Roderick Murchison in 1839 after the sequence of sandstones found in Caer Caradoc Hill just north of Church Stretton in Shropshire, England.
The Gull River and Bobcaygeon formations of the Black River Group capture nearshore sediments while the overlying Lindsay, Verulam and Cobourg limestones of the Trenton Group record a deeper fossil rich continental shelf environment teeming with trilobites, corals, bryozoans and crinoids. These carbonate sequences are succeeded by the Simcoe and Lorraine groups that reflect a tectonically driven shift to siliciclastic sedimentation where weathered and eroded silicate rich rock and sediments were transported into the basin during the Taconic Orogeny.
The Taconic Orogeny was a major Ordovician mountain-building event that transformed the eastern margin of ancient North America known as Laurentia. Caused by the collision of a volcanic island arc with Laurentia it closed the Iapetus Ocean and started the formation of the Appalachian Mountains. The influence of this collision reached far into Ontario where the once tropical carbonate platforms gave way to siliciclastic sedimentation.
This transition marked the end of the Great American Carbonate Bank (GACB) a Sauk megasequence of sedimentary rock representing one of North America’s earliest and most extensive continental transgressions that started back in the Precambrian. During the Sauk transgression, rising seas inundated much of the continental interior or North America, depositing widespread sandstones, shales and limestones on top of Precambrian basement rocks. The sediments that now make up Bay of Quinte bedrock were first accumulated as calcareous muds. Over time the shells and skeletons of benthic animals that lived on the sea floor were buried, compacted and cemented.
During the Pleistocene Epoch, Ontario and much of North America was covered by the vast Laurentide Ice Sheet, a continental glacier that repeatedly advanced and retreated over millions of years. Originating from the Labrador-Ungava Plateau and Arctic islands, with its central dome over Hudson Bay, the ice sheet reached thicknesses of up to 3,000 meters and a maximum extent covering more than 13 million square kilometers. Its immense weight and movement sculpted this landscape, carving out the basins that would become the Great Lakes and shaping countless smaller lakes and landforms across the Canadian Shield and removed the soil and softer rocks to expose the outcrops at the Bay of Quinte. Wave action continues to expose the outcrops and wash fossils free along shorelines such as Presqu’ile and Belleville’s Zwick’s Centennial Park making the Bay of Quinte an accessible fossil-hunting landscape.
The Bay of Quinte fossil assemblage preserves a diverse array of Ordovician marine invertebrates, including trilobites (Ceraurus and Hemiarges), brachiopods including strophomenids, rhynchonellids, orthids and rarer atrypids along with gastropods, bryozoans and rugose corals. These fossils reflect the rich biodiversity of the tropical seas that once covered the region and are often found in limestone along the shorelines of North Beach Provincial Park, Potter’s Creek Conservation Area, Presqu’ile Provincial Park and Zwick’s Centennial Park. Many specimens occur as molds, casts, or recrystallised shells. Visitors can responsibly explore these areas or decide to learn more about Ontario’s Ordovician heritage and visit the Quinte Museum of Natural History.
