The province of Ontario contains many sites of outstanding geological importance. Many are internationally well known and attract visitors from around the globe. Others no less important remain hidden in plain sight.

During the last 3 billion years Ontario has been witness to giant tectonic collisions as North America collided in turn with South America and Africa creating huge mountains now long gone. Many of Ontario's northern rocks originated as magma on ancient ocean floors long before life flourished. The province has been dented by fiery meteorites, drifted across the equator, been flooded by tropical seas rich in marine life and scraped bare by ice sheets.

Ontario's rich geologic history is illustrated here by short descriptions of more than 200 field sites ranging from Timmins in the north to Windsor in the south. These include the Sleeping Giant near Thunder Bay; Agawa Canyon; the Sudbury meteorite crater; Niagara Escarpment; the Falls and Gorge; numerous caves, the mineral-rich Bancroft area; and the high lakeshore cliffs at Scarborough Bluffs. Some sites are sacred to First Nations and are associated with spectacular rock art.

Also included are sites from adjacent parts of Quebec such as the Monteregian Hills near Montreal, the Gatineau Hills at Ottawa and a few sites in New York State, all of which add to the story of the geological evolution of Ontario and all of which are all within easy driving distance from Ontario. Each site features a short summary of its significance and is depicted on a map with GPS coordinates.

Take a drive through our geology and take a few moments to think of Ontario's long and varied history.

Nick Eyles
holds a Ph.D (East Anglia) and D.Sc. (Leicester) and is Professor of Geology at the University of Toronto. His prime research interest is in glacial sedimentology and has many years' experience with field work at modern glaciers. He has worked at the universities of Leicester, Newcastle upon Tyne and East Anglia in Great Britain, at Memorial University in Newfoundland and has been at Toronto since 1981 when he was awarded a prestigious NSERC University Research Fellowship. He has authored more than 150 publications in leading scientific journals on ice age geology and environmental geology and has conducted geological fieldwork from the Arctic to the Antarctic, including work with the Ocean Drilling Program onboard the drillship Resolution. Recent sabbaticals have been held in Brazil and Australia. His other books include Canada Rocks and Ontario Rocks.

Nick Eyles' profile page

• Winner, Geoscience Information Society Best Guidebook Award