Burgess Shale Site

Site of fossil-bearing rock formations created over 500 million years ago by a mud slide, in Yoho National Park, British Columbia, Canada. The shales in this corner of the Rocky Mountains contain more than 120 species of marine invertebrate fossils. One of the world's most important fossil sites, it has been a UNESCO World Heritage Site since 1981.

Although discovered 1909 by US geologist Charles Walcott, the Burgess Shales have only recently been used as evidence in the debate concerning the evolution of life. In Wonderful Life (1990) Stephen Jay Gould drew attention to a body of scientific opinion interpreting the fossil finds as evidence of parallel early evolutionary trends extinguished by chance rather than natural selection. However, more recently both Gould's theories and the site's supposed uniqueness have been called into question.