Cavern Lake

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An intriguing assortment of geological and biological elements explains why this area above Lake Superior’s north shore has been given special protection. The area features a rocky canyon outcrop covered in rare arctic-alpine plants. Also found here is a large cave occupied by colonies of bats. The natural environment of the reserve is considered to be so vulnerable that visitors are discouraged. The Bat Cave As at nearby Ouimet Canyon, jointing planes in the quartz monzonite and late Precambrian diabase rock have produced a canyon more than 48 metres deep. About 27 metres above Cavern Lake is what is considered to be the largest cave in Precambrian rock in Ontario, and possibly in Canada. The entrance measures 20 metres wide by 2.5 metres at its highest point, and the interior extends 13 metres horizontally from front to back. The cave is home to at least four species of bat: the little brown bat, the big brown bat, the rarer Keen’s long-eared bat, and the red bat. In the summer the cave is a roosting site, and in winter a hibernation site. Disturbances may prove harmful to these small winged mammals, especially in winter. Arctic and Sub-Arctic Vegetation Boreal forests—white birch, trembling aspen, spruces, balsam fir, jack pine—cover the dramatic landscape, which is made up of mesas and escarpments. Sub-arctic thickets and a variety of arctic-alpine flora grow on the canyon floor, where snow may generally be found until late spring. Fir-club moss and lichen cover diabase blocks and boulder talus, mixing with alpine woodsia, arctic pyrola, encrusted saxifrage, and fragrant shield fern—plants that are usually found further north. Park Facilities and Activities There are no visitor facilities or amenities.

Location: About 40 kilometres east of Thunder Bay.

Facilities and Activities summary



Tread Lightly. Nature Reserve
General Information
(807) 475-1495
Size: 188.99 ha
Year established: 1975
Park Classification: Nature Reserve
Northwest Zone Suite 221 435 James Street South
Thunder Bay
P7E 6E3
Operating Dates

Not applicable.