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The Burgess Shale

The Burgess Shale is a scientific treasure trove. Usually, only the bones and shells of organisms tend to end up as fossils. But the Burgess Shale bestiary is almost exclusively composed of soft-bodied animals that in normal circumstances would stand no chance of being preserved. Given these exceptional fossils and the site's unique position at the tail end of one of the most important evolutionary events in life history - the rise of animals during the Cambrian Explosion - it is perhaps unsurprising that the Burgess Shale has attracted, and continues to attract, researchers from around the world.

Even though more than a hundred years have passed since the discovery of the main Burgess Shale site, field research continues to turn up new fossils, and many recent discoveries are waiting to be described. A number of previously-known species now need to be revised, thanks to the recovery of better fossil specimens, the development of innovative analytical techniques, or new interpretations.

Workers in the Burgess Shale use a sledgehammer

Extent of the Royal Ontario Museum excavations below the Walcott Quarry in 1999. Mount Burgess in the background.

© Royal Ontario Museum. Photo: Jean-Bernard Caron.

In this section, we present an overview of the current state of knowledge regarding the environment of the Burgess Shale, the extraordinary fossils founding the area, and how these came to be preserved. Many interpretations, ranging from the affinities of some animals to the exact factors allowing their preservation, are still hotly debated and the subject of healthy discussions among scientists.