Ask any mountaineer why they climb, and in some form their answer will embody elements of curiosity, adventure and the age-worn “because it’s there” philosophy. So it’s not hard to imagine cavers – a fraternity of introverted alpinists who prefer plumbing depths to scaling heights – being possessed of similar convictions. But where these geotactical brotherhoods share a common credo, the experiences they define could not be more different.
by Leslie Anthony
Mountaintops boast big spaces and sweeping views where, fresh from scouring far-off corners of the earth, mighty winds tug at your clothing and imagination. Broad horizons and tenuous purchase atop a mass of ice and rock engender paradoxical feelings; you’re at once both master of the world and its most insignificant component. Conversely, caves offer the antithesis: instead of bright and open you get dark, dank and wet – stagnant air and horizons reduced to your fingertips; it’s claustrophobic and cramped; you wedge into spaces that barely permit passage; and, in place of roaring winds there’s virulent silence – so pervasive it’s an entity unto itself.
While this alien milieu is unattractive to some, these same attributes appeal to the keen caver. And, despite the litany of discomfort, fascination with underground passages has been a theme in human history and culture. From the prehistoric cave art of southern France to Roman catacombs, from Jules Verne’s Journey to the Center of the Earth to Tom Sawyer’s escape from a murderous pursuer in a Missouri cave, and from tunnels dug into riverbanks as kids to the high-tech grotto under stately Wayne Manor in Gotham City, caves thread archaeology, literature, even Hollywood. The best way to understand this affinity is to find your own way into a cave, and you can do it right here in Ontario.
Ontario’s 250ish known caves are somewhat pedestrian (over 80 percent are under 50 metres long) compared to offerings elsewhere (Kentucky’s Mammoth Cave, for instance, has over 500 kilometres of passages). Nevertheless, they offer a reasonable intro to the subterranean scene, ideally suited for those with more casual interests in being generally small, accessible, and low on the scales of difficulty and danger. Ontario’s caves are mostly restricted to the southern tier of the province which, given how they’ve formed, isn’t all that surprising.
Cave Geology: A Primer
Underground caverns almost always represent the dissolving action of groundwater on soluble sedimentary rock. Thus, caves are subterranean openings in soluble rock strata. In carbonate rock like limestone, caves usually form a three-dimensional network of chambers and passages controlled by the inherent joint system and bedding planes. Other cave systems exhibit a linear or branching pattern that follows the course of erstwhile underground streams.
Cave origins are hotly debated by speleologists (cave specialists): are they formed above or below the water table? Most known caves lie above, but has it been the case throughout their history? Evidence suggests not, instead pointing to a two-cycle origin. In the first, circulating groundwater dissolves rock along joints and bedding planes. The second cycle begins when the cave emerges above the water table – either through uplift of the land or lowering of the water table – and the action of underground streams causes further enlargement. Meanwhile, calcium carbonate and other solutes accumulate on the walls, ceiling and floor of the cave when surface water seeps in, the most obvious being deposition in the form of stalactites (hanging from the ceiling), stalagmites (rising from the floor), and other dripstone features. These are more common in larger chambers where moisture evaporates from the floor, condenses, runs across the ceiling, dissolves more rock, and then precipitates (drips) off irregularities. Unfortunately, very few of Ontario’s caves boast such spectacular features.
Where can you go?
You’ve got a headlamp, tough pants, sturdy boots, kneepads and a helmet, but where to go? Southern Ontario is underlain by very old (about 600-500 million years before present) sedimentary rock of the soluble variety, and Ontario’s caves are concentrated (typically) in areas where this limestone is exposed to the surface: the Niagara Escarpment (from Niagara north to Tobermory and Manitoulin Island); limestone plains (notably east of Guelph and east of Peterborough); and the Ottawa Valley.
Many of those along the Escarpment are “crevice” caves – caused by large limestone blocks sliding away from the parent formation on underlying shale. Water both causes and exacerbates such processes, more often resulting in deep fissures than cozy caverns. Even these, however, can be fun to explore. In Halton Region, at Rattlesnake Point and Kelso Conservation areas, south at Mount Nemo and right here at Metcalfe Rock, you’ll find fissure caves up to 20 metres deep and 100 metres long. Deeper ones require ropes and a guide, but for the most part they’re simply great places to scramble around and get dirty on a hot summer day, shimmying down limestone chimneys to where the air is cool, damp, and smells like moss.
Cave temperature is another source of fascination. Though these tend to be coolish, they’re often remarkably constant. At Warsaw Caves Conservation Area east of Peterborough, the temperature in seven caves varies no more than 2 – 3˚C degrees year round. Each has a characteristic temperature; most are 12 – 14˚C, a result of the latent heat of the earth, but Cave 4 – a glaciere cave – is 0 – 2˚C, boasting ice on even the hottest summer day. In winter, cave entrances are ringed with frost formations caused by the escaping warm, moisture-laden air.
Warsaw Caves are great for families because they’re safe and located in a conservation area with hiking trails, canoeing and other interesting geological features. Formed by groundwater draining pro-glacial Lake Algonquin and elevated as the land rebounded from the weight of the glaciers, Warsaw Caves were once much larger, having collapsed as the glacial torrent was reduced to the quiet Indian River that now even disappears underground for a stretch. Still, these caves contain interesting things – flint chips embedded in limestone strata, ancient seabed fossils, and spider colonies strategically set where a steady supply of insects cascades down from above.
Because they’re a tough place to make a living, many animals use caves, but fewcall them home. Ontario doesn’t have huge cave-based bat colonies like tropical America and the Caribbean (though the Royal Ontario Museum has nicely recreated a Jamaican bat cave), but a few do have closed seasons because of hibernating bats. Otherwise, Ontario caves boast an assortment of microorganisms, arthropods, rodents and the occasional porcupine. Most animals tend to vacate heavily used caves, one reason wildlife may seem scarce to a visitor. In other parts of the world, older cave systems feature entire ecosystems based around the feces deposited by bat colonies; beetles and crickets feed on the dung, spiders eat the insects and larger animals hunt the spiders and bats. Some of these caves also support bizarre forms of insect, spider, crustacean, amphibian and fish committed to the subterranean lifestyle, having surrendered the metabolic costs of eyes and skin pigment – unnecessary in a world without light – for enhanced tactile and chemosensory features to root around in search of tiny invertebrates, an adaptation termed “troglodytic.”
Ontario has few troglodytes. In addition to being relatively cave-poor despite its ideal bedrock, Ontario’s caves are too young; the glaciers didn’t disappear until 10,000 years ago, and the majority of caves were created from glacial meltwater. A variation are the grottos and “sea caves” along the Bruce Peninsula, like recently reopened Greig’s Scenic Caves near Lion’s Head where parts of the movie Quest For Fire were filmed. These dozen sea caves were eroded by wave action on the base of the Escarpment when water levels were 100 metres higher than today. Unlike most of Ontario’s caves, they’re large enough to have been used by aboriginal peoples.
Fossils abound at Greig’s and also further south at Collingwood Scenic Caves, but the best fossils are found in the Bonnechere Caves near Eganville, northwest of Renfrew. The province’s largest commercial cave venture, formed on an isolated limestone outcrop by an early version of the Bonnechere River, these family-owned caverns feature boardwalks and lighting, perfect for those who prefer walking to crawling.
If you visit any of Ontario’s caves you’ll notice that they’re fragile environments, easily damaged by littering, graffiti or the touching of delicate formations. Unfortunately, conservation came too late for many. Spelunkers (though most don’t like to be called by this ’50s fad term) sarcastically note that the biggest hazard in Ontario’s caves is broken glass. Worse is the rapid disappearance of dripstone formations thousands of years in the making. In the 1800s the main chamber of a cave near Rockwood was decorated with stalactites and stalagmites, but has since been stripped bare. Likewise a spectacular cave on private property in the Ottawa Valley was still fully intact in 1965 but totally destroyed by vandals within 10 years.
I saved this distressing news not because I wished to end on a bad note or a soapbox, but because although dripstone formations are nice decorations, with or without them caves are windows on a much deeper history – their darkness and silence a fit setting for going back in time, whether to coral seas or glacial lakes. Caves aren’t mountaintops, but they needn’t be.
Warsaw Caves: warsawcaves.com
Bonnechere Caves: bonnecherecaves.com
Greig’s Scenic Caves: showcaves.com/english/ca/caves/Greig.html
Collingwood Scenic Caves: sceniccaves.com
Kelso, Rattlesnake Point, Mount Nemo: conservationhalton.on.ca
Ontario Caving Resources and Groups: cancaver.ca/prov/ont.htm