The Burgess Shale, which is about 505 million to 510 million years old, is a treasure trove for paleontologists like Caron because “it represents the roots of our modern diversity,” he says. There have been discoveries of Burgess Shale-type fossils elsewhere in the world, “but nothing really beats the quality of preservation and the diversity of the Burgess Shale,” says Caron. The preservation is so exceptional that paleontologists can see soft tissue like eyes, guts and brains.

Eyes and brains were characteristics that evolved during the Cambrian period, especially during the “Cambrian Explosion” — a mass radiation of complex life that saw the appearance of almost all major animal phyla. “After the Cambrian, you see all what we call animals, organisms which can move around, eat others, have complex feeding behaviours or ecologies. They can walk, they can swim with their appendages, they can see.”

This November marks 50 years of Burgess Shale research at the Royal Ontario Museum. “I always compare the Burgess Shale to a bottle of nice Bordeaux wine,” says Caron. “With age, it gets even better.”