The Ancient Fossils of Burgess Shale in British Columbia
British Columbia’s Burgess Shale is a palaeontologist’s dream, holding layers of fossils from 540 million years ago. The fossils give a glimpse into the very spark of life.
The soft-bodied creatures with no vision wiggled and squirmed in the Pre-Cambrian mud. But their secluded world was transforming, bursting with new life forms over a few million years. Hard shells, skeletal structures, limbs and even eyes formed in the middle Cambrian, the era known as the Cambrian Explosion. Discovered in southeastern British Columbia, the fossils of animals long gone, and the precursors of animals today, were found at Burgess Shale.
Ancient “Stone Bug” Fossils in B.C.
As part of his duties as head of the Smithsonian Institute, palaeontologist Charles Doolittle Walcott toured North America in his search for Cambrian fossil evidence of life over 540 million years ago. In 1886, Canadian geologist R.G. McConnell heard about “stone bugs” unearthed by workers laying track for the Canadian National Railway. The “stone bugs” were trilobite fossils, creatures that were captured forever in the shale, limestone and slate of Mt. Stephen in Yoho National Park. In 1907, Walcott made his way to Mt. Stephen in the Canadian Rockies near the town of Field to have a look.
Image of a Trilobite, a Burgess Shale creature. Dinopedia.
The trip was well worth the renowned scientist’s time. Buried in the rock before Walcott’s eyes were countless remnants of prehistoric life, animals captured hundreds of millions of years before the dinosaur era. Previously underwater, the fossil stratigraphy is now located high in the British Columbia mountains. “He collected fossil specimens from the trilobite beds, and returned in 1909 to map similar geological rock layers on the other side of the valley,” said Parks Canada – Teacher’s Corner – Burgess Shale.
Walcott also found more types of arthropods, phyllopods, sponges, “lace crabs” and other fascinating creatures of the past. The next summer, 60-year-old Walcott came back to Canada and brought along his family to help in his search for more fossils. Walcott named the site the Burgess Shale, after the closely situated Burgess pass, and one site became known as the Walcott Quarry.
Phyllopod Beds in the Burgess Shale
“Walcott established his quarry in the phyllopod bed of the Burgess Shale and worked with hammers, chisels, long iron bars,” said Stephen Jay Gould in Wonderful Life: The Burgess Shale and the Nature of History (W. Norton and Co., New York 1989, pg 75), and surprisingly, “small explosive charges for a month or more each year from 1910 through 1913.” Taking thousands of samples back to the Smithsonian in Washington, D.C. (in all, he collected 65,000 fossil specimens), Walcott made thorough notes with photographs and detailed descriptions and also published papers about his spectacular, momentous addition to the fossil record.
When the excitement was died down, Walcott’s work laid unseen in work drawers. In 1930, Percy Raymond of Harvard University located another lode of fossils above Walcott’s Quarry. That area was dubbed “Raymond Quarry”; it contained a different range of undersea fossils.
The Burgess Shale Expanded in 1980s
Under the direction of Professor Henry Whittington of Cambridge University (England), the Geological Survey of Canada put the Burgess Shale in their sights and began research in 1966. By 1972, a new means of examining fossils was devised, so that the three-dimensional shapes could be examined, not only the flat surface.
Section of the Burgess Shale, Andrew MacRae, 1995
The professor and students explored “evolutionary relationships existing between some of these bizarre ancient animals and modern-day forms,” said Parks Canada, “and found that a handful of fossils appeared to be unrelated, or “failed” evolutionary experiments.” Further examinations continued throughout the 1980s, enlarging the Burgess Shale over a 20-kilometre area. Dr. Desmond Collins of the Royal Ontario Museum and his researchers “collected many thousands of unique and bizarre fossils, making many important new discoveries.”
Collection procedures no longer include explosives. Excavations are completed cautiously by hand, drilling holes and prying off the rock, rather than blasting it away. Peculiar creatures unrelated to today’s life include the soft-bodied “Opabina Regalis” with a long snout and five eyes. Also extinct, the “Hallucigenia” was another strange fossil found at Burgess Shale. It seems to have no head and long spines, top and bottom. The lower spines appear to have been for walking; perhaps the top spines were for protection.
Canadian Fossil Beds Part of World Heritage Site
The Canadian Rocky Mountain Parks were named World Heritage Sites in 1981 and 1990. The Burgess Shale is specifically included. As “one of the most significant fossil areas in the world… the Burgess Shale fossils provide key evidence of the history and early evolution of most animal groups known today,” according to the UNESCO listing, and “yield a more complete view of life in the sea than any other site for that time period.”
While there are guided hiking tours of Yoho National Park’s Burgess Shale, collecting of fossils and rocks is not permitted, and parts of the quarries are off limits except for researchers. Visit the Burgess Shale Geoscience Foundation for a wealth of information and a glimpse of Canada’s fascinating ancient history.
This article first appeared on Suite101.com in 2010. Copyright Susanna McLeod