Burgess Shale Bc Canada

The Burgess Shale was discovered by accident in 1909, and the animals it contains are so strange that some early researchers thought they were reconstructing them upside down

Charles Walcott, the secretary of the Smithsonian Institution, stumbled on the Burgess Shale fossil beds in Yoho National Park, British Columbia, in August 1909, reportedly when his horse slipped on loose rock near Burgess Pass. What he found was a window into a moment 508 million years ago, when soft-bodied animals were preserved in unusually fine sediment at the base of an ancient reef wall. At that period, soft tissues almost never fossilise. Here they did: guts, eyes, muscles, gills, and the full body plans of animals that left no living descendants.

The creatures in the Burgess Shale became famous in science partly because they are so alien. Hallucigenia was initially reconstructed upside-down and back-to-front; the spines that researchers thought were legs turned out to be dorsal defences. Anomalocaris, at 50 centimetres, was the apex predator of its world and had no anatomical relationship to anything alive today. Opabinia had five eyes and a feeding appendage with a claw at the end. The Cambrian explosion – the rapid diversification of complex animal life beginning around 541 million years ago – is visible here in direct physical form.

Getting There

The Burgess Shale sites are in Yoho National Park near the town of Field, British Columbia. Parks Canada requires all visitors to join guided hikes operated by certified interpreters; no independent access to the fossil beds is permitted. This is not bureaucratic obstruction – the fossils are fragile and the scientific stakes are high enough that protecting the sites is genuinely important.

Two main sites offer guided access. The Walcott Quarry hike is 20 kilometres return with 760 metres of elevation gain, taking 8-10 hours. The Mount Stephen Trilobite Beds hike is 6 kilometres return with 520 metres of elevation gain, taking 4-5 hours. Both require reasonable fitness for steep mountain terrain at altitude. Booking through the Burgess Shale Geoscience Foundation (burgess-shale.bc.ca) is essential; trips are limited in size and fill weeks or months in advance for summer dates.

The town of Field is small; accommodation consists of several guesthouses and the Emerald Lake Lodge (the upscale option, about 10 kilometres from town). Yoho is adjacent to Banff and Kootenay national parks, making it a natural addition to a broader Rocky Mountain itinerary.

The Context

Stephen Jay Gould’s 1989 book “Wonderful Life” brought the Burgess Shale to wide public attention with the argument that the diversity of Cambrian body plans was radically broader than anything alive today and that evolution’s subsequent path was shaped by contingency rather than inevitability. Later researchers disputed some of Gould’s interpretation – the alien-looking creatures turned out to be connected to living phyla more closely than he claimed – but the book remains the best popular treatment of the site’s significance and is worth reading before the hike.

The fossils themselves are in the Royal Ontario Museum in Toronto and the Smithsonian in Washington, not on-site. What you see on the hike are the actual rock formations, the quarry faces, and the context for understanding how the preservation happened. This is more interesting than it sounds if you arrive with the background.