Why a 505-million-year-old cliff in Canada holds the secrets to life on Earth

Countries & Cities · Published 29 September 2026 Swipe more like this →

In short: The Burgess Shale is a treasure trove of Cambrian life, capturing soft-bodied organisms in exquisite detail. Discovered in 1909, this site transformed our understanding of evolution, revealing a bizarre world of ancient creatures that defy modern classification. It remains a vital window into the history and future of our planet.

Located in the Canadian Rockies of British Columbia, the Burgess Shale is a fossil-bearing deposit dating back about 505 million years to the middle Cambrian. It is renowned for the exceptional preservation of soft-bodied organisms, which are typically lost to decay. These fossils, often preserved as carbonaceous films less than one micrometre thick, were likely entombed by rapid sediment-rich water currents. The site's unique preservation is linked to its position at the base of a 160-metre-tall cliff formed by the Cathedral Formation, which protected the beds from tectonic compression.

Palaeontologist Charles Walcott discovered the site on 30 August 1909 and spent years amassing over 65,000 specimens. Initially, Walcott attempted to force these fossils into known living taxa, a classification approach now largely rejected. It was not until the 1960s, through the work of Harry Blackmore Whittington and his students, that the true, bizarre nature of the fauna was revealed. Organisms like the five-eyed Opabinia and the spine-covered Hallucigenia demonstrated that Cambrian life was far more diverse and anatomically unusual than previously imagined.

The site's significance sparked a famous intellectual debate between Stephen Jay Gould and Simon Conway Morris. In his 1989 book Wonderful Life, Gould argued that the Burgess Shale represented a unique evolutionary experiment with disparate body forms that largely went extinct. Conversely, Conway Morris maintained that these animals could be classified within modern phyla. Today, the Burgess Shale is a UNESCO World Heritage Site, recognized for its role in understanding the Cambrian explosion and even predicting the long-term future of Earth's climate as the Sun expands and oxygen levels decline.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Why the world's most important Coal Age fossils are hiding in plain sight
• Why this remote Quebec cliffside is a vital window into ancient life on Earth
• Before the Cambrian, Earth's first big organisms looked like quilted mattresses
• How a foggy Newfoundland headland became the cradle of Earth's earliest complex life
• The Paleozoic's starting line is a burrow in Newfoundland
• Butrint: The Ancient Mediterranean Port That Survived Empires, Earthquakes, and Centuries of Abandonment
• From Danube gunboats to NATO frigates: the evolving history of the Bulgarian Navy
• Bwindi Impenetrable National Park: A High-Altitude Refuge for Half the World's Mountain Gorillas
• Why a small Belgian lane became a permanent piece of the British Empire
• Byblos: The Ancient Lebanese City That Gave Its Name to the Bible
• How an ancient volcanic eruption sparked one of the world's oldest engineering feats
• Can a global tourism hotspot save one of the world's rarest primates from extinction?

More in World Heritage Sites · More in Countries & Cities · Latest · A–Z · All topics