Discovery, Collection, and Re-examinations
The first Burgess Shale fossils were found on Mount Stephen in Canada's Rocky Mountains by a construction worker, whose reports of them reached Richard McConnell of the Geological Survey of Canada. McConnell found trilobite beds there in 1886, and some unusual fossils that he reported to his superior. These were misdiagnosed as headless shrimps with unjointed appendages, and were named Anomalocaris because of their unusual appendages – but turned out to be pieces of a puzzle that took 90 years to solve.
Similar fossils were reported in 1902 from nearby Mount Field, another part of the Stephen formation. These may have been why Charles Doolittle Walcott visited Mount Field in 1909. While taking photographs there Walcott found a slab of fossils that he described as "Phyllopod crustaceans". From late August to early September 1909, his team, including his family, collected fossils there, and in 1910 Walcott opened a quarry that he and his colleagues re-visited in 1911, 1912, 1913, 1917 and 1924, bringing back over 60,000 specimens in total. Walcott was Secretary of the Smithsonian Institution from 1907 to his death in 1927, and this kept him so busy that he was still trying to make time for analyzing his finds two years before his death. Although he drew attention to the exceptional detail of the specimens, which were the first known fossils of soft-bodied animals from the Cambrian period, he also had other research interests: the Early Paleozoic stratigraphy of the Canadian Rockies, which took up the great majority of his time there; and Precambrian fossils of algae and bacteria, to which he assigned as much importance as to the fossils of animals. He managed to publish four "preliminary" papers on the fossil animals in 1911 and 1912, and further articles in 1918, 1919 and 1920. Four years after Walcott's death his associate Charles Resser produced a package of additional descriptions from Walcott's notes. Walcott's classifications of most of the fossils are now rejected, but were supported at the time, and he accepted a change for one of the few where his conclusion was disputed. Many of the later comments were made with the benefits of hindsight, and of techniques and concepts unknown in Walcott's time.
Although in 1931 Percy Raymond opened and briefly excavated another quarry about 20 metres (66 ft) above Walcott's "Phyllopod bed", there was very little interest in the Burgess Shale fossils from the 1930s to the early 1960s, and most of those collected by Walcott were stored on high shelving in back rooms at the Smithsonian Institution. Between 1962 and the mid-1970s Alberto Simonetta re-examined some of Walcott's collection and suggested some new interpretations. Beginning in the early 1970s Harry Whittington, his associates David Bruton and Christopher Hughes, and his graduate students Derek Briggs and Simon Conway Morris began a thorough re-examination of Walcott's collection. Although they assigned groups of fossils to each member of the team, they all decided for themselves which fossils to investigate and in what order. Their publications and Stephen Jay Goulds' popularization of their work in his book Wonderful Life aroused enduring scientific interest and some public interest in the Cambrian explosion, the apparently rapid appearance of moderately complex bilaterian animals in the Early Cambrian.
The continuing search for Burgess Shale fossils since the mid-1970s has led to the description in the 1980s of an arthropod Sanctacaris and in 2007 of Orthrozanclus, which looked like a slug with a small shell at the front, chain mail over the back and long, curved spines round the edges. Recent digs have discovered species yet to be formally described and named. They have also unearthed more and sometimes better fossils of animals that were discovered earlier, for example Odontogriphus was for many years known from just one poorly preserved specimen, but the discovery of a further 189 formed the basis for a detailed description and analysis in 2006. Re-examination of Walcott's collection also continues, and has led to the reconstruction of the large marine animal Hurdia in 2009.
Read more about this topic: Fossils Of The Burgess Shale