Just over a hundred years ago, in 1909, the noted American palaeontologist Charles Doolittle Walcott

Just over a hundred years ago, in 1909, the noted American palaeontologist Charles Doolittle Walcott discovered something strange in the Canadian Rockies. Ghostly imprints were etched into the rock, faintly delineating the twisted filaments of legs or antennae. A myriad of ancient organisms, five hundred million years old, were pressed between the layers of shale, their soft tissues intricately preserved.In many ways, Walcott had hit the palaeontological jackpot, as the fossil beds in what became known as the Burgess Shale formation contained some of the oldest, most diverse and best-preserved fossils known at the time. Soft tissue preservation was unprecedented in rocks of this immense age, and the Burgess Shale allowed scientists to examine an ancient ecosystem almost as it would have appeared when the animals were alive. The fossils were numerous and bizarre; along with the ones shown in the photos, Marella and Canadia (trilobite and annelid worm ancestors respectively) stranger forms were found, such as Opabinia, with a cluster of five eyes and a proboscis, and Hallucigenia, with a double row of long spines down its back. Derek Briggs and Simon Conway Morris, later to become famous as influential writers and theorists, concluded that a lot of the species in the Burgess shale had no modern descendants, and represented ancient groups - phyla - unknown from any other period in time. Based on these findings, the evoluntionary biologist Steven Jay Gould wrote a famous book (Wonderful Life) postulating that the animals had been failed evolutionary ‘experiments’ which died out as more well-adapted forms emerged.Study of the site has been ongoing into the present day, and a better understanding of the species has led to the evolutionary experiment hypothesis to be largely abandoned, as many of them have now been fitted into existing groups. In 2014, a new Burgess Shale outcrop was announced: by the time the find went public, at least fifty species had already been found, and species new to science are still being discovered.-TJTThe photos show the fossils Marella, a trilobite precursor, and Canadia, related to the ringed worms (annelids). They were found on the Smithsonian Museum’s website, where a lot more information on the discovery of the Burgess Shale Formation can be found. http://bit.ly/1G6Fwwv -- source link

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