Burgess Shale

The Burgess Shale is a fossil-bearing sedimentary rock unit exposed in the Canadian Rockies of British Columbia, Canada. Dating to the Middle Cambrian around 508 to 505 million years ago, it is famous for the exceptional preservation of soft-bodied fossils (making it a Lagerstätte), generally preserved as very thin dark carbonaceous films. The rock unit is a black shale and crops out at several localities near the town of Field in Yoho National Park and the Kicking Horse Pass. Another outcrop is in Kootenay National Park 42 km to the south. It is one of the best known Cambian Konservat-Lagerstätten, preserving a key record of the Cambrian explosion.