Burgess Shale Cambrian Palaeontological Record


Anomalocaris canadensis from the Burgess Shale

Anomalocaris canadensis from the Burgess Shale, an extinct arthropod and the top Cambrian predator. ROMIP 51211. (© Royal Ontario Museum 2021 – Image J.-B. Caron).

Geological Period

Cambrian / Miaolingian

Main geological interest




Yoho and Kootenay National Parks, British Columbia, Canada.
51°26’18.0″N, 116°28’20.0″W

Anomalocaris canadensis from the Burgess Shale, an extinct arthropod and the top Cambrian predator. ROMIP 51211. (© Royal Ontario Museum 2021 – Image J.-B. Caron).

Characterized by exceptional soft-tissue preservation, contains the most complete fossil record of Cambrian (Wuliuan) marine ecosystems.

The Walcott Quarry in Yoho National Park is the best-known and most visited Burgess Shale site. Together with the nearby Trilobite Beds on Mount Stephen, it was designated a UNESCO World Heritage Site in 1980 because “the Burgess Shale fossils provide key evidence of the history and early evolution of most animal groups known today, and yield a more complete view of life in the sea than any other site for that time period”. It is a key global reference for Cambrian sites exhibiting similar taphonomic characteristics that are referred to as “Burgess Shale-type” deposits (Gaines, 2014).

Parks Canada guide with visitors on a Burgess Shale interpretive hike at the Walcott Quarry, Yoho National Park. (© Parks Canada / Ryan Creary).

The Burgess Shale has proved critical to the scientific understanding of the Cambrian explosion, an event that marked the first appearance of recognizable animals in the fossil record. Characterized by exceptional preservation of soft-bodied organisms, the Burgess Shale yields an extraordinary diversity of marine animals that lived along or near the Cambrian seafloor, including sponges, ctenophores, cnidarians, echinoderms, hemichordates, chordates, chaetognaths, molluscs, annelids, priapulids and arthropods, in addition to cyanobacteria and algae. This site provides a wealth of information for a range of paleoecological and evolutionary studies, including research into some of our deepest relatives (eg. Morris and Caron 2013), and also provides the basis for large scale quantitative palaeocommunity studies due to the abundance of specimens preserved at multiple sites (eg. Nanglu et al., 2020).

Burgess Shale fossils are found at several locations within the regional Stephen Formation clastic sedimentary sequence in Yoho National Park and Kootenay National Park. The Stephen Formation is divided into “thin” and “thick” expressions representing platformal and basinal facies respectively (Aitken and Fritz, 1968). Burgess Shale fossils occur mainly in the thick Stephen Formation where it consists of a succession of thin-bedded mudstones, claystone, and carbonate up to 300m thick.

Discovered by Charles Walcott in 1909, the Burgess Shale experienced a resurgence of research in the latter half of the 20th century (Morris, 1998). Since 1975, the Royal Ontario Museum has been conducting ongoing research on the Burgess Shale resulting in significant new discoveries (eg. Caron et al., 2014).

Burgess Shale localities within part of the Canadian Rocky Mountain Parks World Heritage Site. © As the Crow Flies cARTography.

Aitken, J.D. and Fritz, W.H. (1968) Burgess Shale Project, British Columbia. (82 H-8, (West Half)). 68–1A, pp. 190–192.

Caron, J.-B. et al. (2014) ‘A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies’, Nature Communications, 5, p. 3210. Available at: https://doi.org/10.1038/ncomms4210.

Gaines, R.R. (2014) ‘Burgess Shale-type Preservation and its Distribution in Space and Time’, The Paleontological Society Papers, 20, pp. 123–146. Available at: https://doi.org/10.1017/S1089332600002837.

Morris, S.C. (1998) The Crucible of Creation: The Burgess Shale and the Rise of Animals. Oxford University Press.

Morris, S.C. and Caron, J.-B. (2012) ‘Pikaia gracilens Walcott, a stem-group chordate from the Middle Cambrian of British Columbia’, Biological Reviews, 87(2), pp. 480–512. Available at: https://doi.org/10.1111/j.1469-185X.2012.00220.x.

Nanglu, K., Caron, J.B. and Gaines, R.R. (2020) ‘The Burgess Shale paleocommunity with new insights from Marble Canyon, British Columbia’, Paleobiology, 46(1), pp. 58–81. Available at: https://doi.org/10.1017/pab.2019.42.

Todd Keith
Parks Canada, Yoho National Park, British Columbia, Canada

Jean-Bernard Caron
Richard M. Ivey Curator of Invertebrate Palaeontology, Royal Ontario Museum, Toronto, Ontario, Canada