A diverse array of animals was found in fossils from the Burgess Shale site in British Columbia,
dating from the Cambrian period.
They include:
Pikaia (swimming eel-like chordate)
Hallucigenia (with spikes on seafloor)
Anomalocaris (large clawed predator)
Marella (arthropod swimming at left)
Ottoia (burrowing U-shaped worm)
Cambrian exhibit at Field Museum.