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The Burgess Shale |
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The Burgess Shale, a series of fossil beds in the Canadian Rockies, was first noticed in 1886 by Richard McConnell of the Geological Survey of Canada (GSC). His and subsequent finds, all from the Mount Stephen area, came to the attention of palaeontologist Charles Doolittle Walcott, who in 1907 found time to reconnoitre the area. He opened a quarry in 1910 and in a series of field trips brought back 65,000 specimens, which he identified as Middle Cambrian in age. Due to the quantity of fossils and the pressures of his other duties at the Smithsonian Institution, Walcott was only able to publish a series of "preliminary" papers, in which he classified the fossils within taxa that were already established. In a series of visits beginning in 1924, Harvard University professor Percy Raymond collected further fossils from Walcott's quarry and higher up on Fossil Ridge, where slightly different fossils were preserved.
Interest in the area's fossil beds faded after Raymond's 1930s expeditions. In the early 1960s Harry B. Whittington was persuaded that further investigation was required, and organised surveys in partnership with the Geological Survey of Canada. These new specimens led him to set up a team to re-examine Walcott's fossils, which had languished in a store-room at the Smithsonian since Walcott's death in 1927. In the early 1970s the team published papers that diagnosed many of the specimens as fossils of previously unknown types of animals, some possibly belonging to new phyla. These analyses heightened interest in the existing debate about whether the Cambrian explosion represented a truly abrupt evolution of recognisable animals or was the result of a longer development, most of which was hidden by gaps in the known sets of fossils that had been found.
All this time no Canadian museum had its own collection of Burgess Shale fossils. In 1975 the Royal Ontario Museum (ROM) began collecting, found 7,750 new specimens around the existing sites, and discovered similar fossil beds up to 40 kilometres (25 mi) away. Their collection currently stands at 140,000 specimens and growing, and the rate at which new species are found suggests that the Burgess Shale will continue to produce important discoveries for the foreseeable future.