It is now appreciated that the Burgess Shale is a site of exceptional fossil preservation, and records a diversity of animals found nowhere else. The Burgess Shale contains the best record we have of Cambrian animal fossils. The locality reveals the presence of creatures originating from the Cambrian explosion , an evolutionary burst of animal origins dating 545 to 525 million years ago. During this period, life was restricted to the world's oceans. At the Burgess locality, sediment was deposited in a deep-water basin adjacent to an enormous algal reef with a vertical escarpment several hundred meters high.
Green areas represent land above sea-level at that time, with red indicating mountain ranges.
Dark blue indicates deep ocean basins, while light blue denotes shallow seas of the continental shelf. In 1909, the Burgess Shale was discovered by Charles D. Walcott of the Smithsonian Institution. The legend has it that his horse stopped in front of a rock which he then cracked open, discovering fossils. Finally in 1960, Alberot Simonella brought a renewed interest to Walcott's work when he began to redefine members of the Burgess Shale fauna. In 1967, the Cambridge project was intiated by Harry Whittington.