On the perimeter of a great carbonate reef at the tip of the North American continent, in a warm shallow sea, there once lived a collection of the most extraordinary creatures the Earth has ever known. After nearly two billion years of simple life forms, a huge spectrum of complex body shapes had evolved in just 10 to 20 million years. Turbulent mudslides buried these animals, cutting them off from decomposing bacteria and preserving them in perfect conditions.
Once buried under 6 miles (10 kilometers) of rock, the re-exposure of the Burgess Shale fossils began 175 million years ago. In 1909, a paleontologist excavated the dark fossil-bearing strata in a 320-foot (100-meter) high limestone cliff. Consisting of over 120 different animal types, the fossils revealed that life in the past was diverse in its body plans—and gave us the present notion of an early “experimental” phase of evolution.
The site forms part of Yoho National Park and is also a World Heritage Site. Hikes can be organized at the Walcott and Raymond quarries, but private collection of fossils or shale is strictly prohibited in case they contain an exciting new find.