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The Parks / Ontario / St. Lawrence Islands National Park

The densely wooded archipelago is really the high points of a Precambrian mountain range that once linked the southern edge of the Canadian Shield and the Adirondack Mountains of New York state, scraped smooth by the passage of glaciers and nearly submerged by the St. Lawrence River. This geological formation, called the Frontenac Axis, a 40 kilometre-wide granite bridge, during the last ice age was buried beneath massive glaciers 3 kilometres thick. When the glaciers receded 12 000 years ago, the mountains were overspread by floodwaters draining into the Atlantic Ocean along the St. Lawrence Valley. Those ancient mountain peaks formed the fragmented string of 20 islands and about 90 rocky shoals and islets - stepping-stones between the landmasses. The geology of the area is predominantly rocky rugged shoreline interspersed with significant wetlands and low vegetated inclines that support a broad range of flora and fauna.