By Parks Canada
Canadian Rocky Mountain Parks World Heritage Site
Explore scientific connections
Join us as we uncover the connections between these fossils and the evolution of early animal life.
Now… let’s figure out how fossils of sea creatures over 500 million years old ended up on top of mountains in British Columbia, Canada!
What are fossils?
When animals and plants die, their bodies typically decompose completely. But when the conditions are just right fossils can be left behind.
Soft tissues typically decompose quickly, leaving only the hardest parts like bones, teeth and shells fossilized.
What makes Burgess Shale fossils so special?
The Burgess Shale fossils are preserved in a way we rarely see.
The fossils are so well preserved that many of their soft tissues remain visible in exquisite detail within the rock. This means we can see eyeballs, guts, brains and (in some cases) even their last dinner!
Visitor and guide study fossils (2018) by Ryan CrearyParks Canada
Why are fossils so important?
Fossils hold important clues for scientists who are trying to understand what plants and animals looked like 500 million years ago. This gives them a better understanding of how things have changed over time.
What can these fossils tell us?
Due to the exceptional preservation of the Burgess Shale fossils, scientists can trace important evolutionary traits back millennia. This helps us understand how these animals lived, interacted and evolved over time.
The Cambrian period
The Burgess Shale fossils are from the Cambrian period of Earth’s history. The period began over 540 million years ago and lasted more than 55 million years.
The Cambrian explosion
This period of time is also called the Cambrian explosion. While there was no actual explosion, complex animal life quickly began to change.
The Cambrian explosion saw a burst of evolution and rapid increase in the diversity of life.
What caused this explosion of life?
Scientists believe that this may have been caused by a combination of climate change and increased oxygen in the atmosphere.
Many animal groups developed in this period, like arthropods - spiders and insects - and chordates - ancestors of vertebrates which include humans!
Life, 500 million years ago
There is evidence of larger and more complex creatures evolving during this period.
As animal diversity and competition increased, we begin to see the evolution of predator-prey relationships. Eyes and jaws - parts not seen before - developed in response to these pressures.
Evolution and adaptation
On the seafloor, sponge-like creatures grew in dense mounds constructing ocean reefs, while hard-bodied animals called trilobites dominated with their highly adaptable segmented bodies.
Never before had the Earth seen such a diverse array of life!
Burgess Shale UNESCO mural (2022) by Marianne CollinsParks Canada
How were the Burgess Shale fossils formed?
Burgess Shale animals lived in much the same way as marine animals live today. We see animals tucked amongst sponges, burrowed in mud, clamped on to rocks, walking the seafloor, and swimming in the water.
A catastrophic event
Stormy weather triggered large mudflows that quickly buried animals living near the seafloor.
A dense layer formed protecting the specimens from scavengers, while fine sediment and lack of oxygen in the environment prevented the further decaying of soft tissues.
Frozen in time
Research suggests that calcium carbonate found on the sediment surface acted as cement, sealing the animals fate. This layer became deeply buried and was subjected to heat and pressure over millennia, eventually forming shale rock.
This shale rock was then thrust upwards through the movement of Earth's tectonic plates, exposing the Burgess Shale fossils in exceptional condition.
As a result, the Burgess Shale fossils are the perfect specimens for today's scientists to study.
Railway workers and stone bugs
In the 1880’s the Canadian Pacific Railway was being constructed through the Kicking Horse Pass, which now makes up part of Yoho National Park.
It was during this period that railway workers and surveyors first reported finding “stone bugs” on Mount Stephen.
Geological Survey of Canada
Following the reports from railway workers, Geological Survey of Canada geologist Richard McConnell was sent to map the geology of the Rockies along the route of the railway line.
McConnell published a report on the geology and the fossils found at Mount Stephen in 1887.
Charles Doolittle Walcott
The discovery of fossils at Mount Stephen attracted the attention of Charles Doolittle Walcott from the Smithsonian Institution.
Walcott was a specialist on Cambrian trilobites and brachiopods who first visited the area in 1907.
Years of exploration
Walcott was so inspired by his initial visit, he returned regularly to continue his research between 1909 and 1925.
Through these years, Walcott excavated through several layers of rock, cataloguing new species with his family by his side.
The Walcott Quarry
One of his greatest contributions to science came with his discovery of the Burgess Shale.
While exploring the mountains north of Mount Stephen in 1909, Walcott discovered numerous fossils from animals previously unknown to science.
Tour group at the Walcott Quarry (2018) by Ryan CrearyParks Canada
Further collections from the site have expanded our understanding of the Burgess Shale deposits and the fossils found here.
Notable collections were made by Harvard University in 1930, the Geological Survey of Canada in 1966-1967 and the Royal Ontario Museum starting in 1975.
Researchers re-examining Walcott’s collection using modern technologies continue to make new discoveries to this day.
While the Mount Stephen and Walcott Quarry sites have yielded the majority of past discoveries, new sites have been found nearby in Kootenay National Park.
Panoranma of the Dawn of Life exhibit at the Royal Ontario Museum (2022) by Paul EekhoffParks Canada
The Dawn of Life at the Royal Ontario Museum
Nearly 200 Burgess Shale fossils are on display at the Royal Ontario Museum's impressive Dawn of Life exhibit.
The exhibit features almost 1,000 fossil specimens that chronicle the evolution of life from 4 billion to 200 million years ago.
Discover the ROM online
An impressive collection of Burgess Shale fossils, including more than 180 species, is displayed digitally on the Royal Ontario Museum's Burgess Shale website.
Both the Dawn of Life exhibit and the virtual museum are excellent resources for information on the latest scientific research, and the many species being discovered at Burgess Shale sites.
Smithsonian National Museum of Natural History
Walcott amassed an impressive 68,000 fossils from the Burgess Shale through the years.
This collection is held at Smithsonian National Museum of Natural History, Washington DC, where a permanent display showcases his discoveries.
Parks Canada - Protect and Present
Parks Canada protects these internationally significant sites and treasures for future generations, ensuring their continued scientific study for years to come.
The Canada National Parks Act and Regulations makes it illegal to remove or deface natural objects in a national park.
Due to its historical and scientific significance, the Walcott Quarry and Mt. Stephen sites are protected under the National Parks Act and closed to casual visitors.
These sites may only be visited on scheduled guided hikes or with a research permit.
The Walcott Quarry
This is the original site where Charles Walcott first discovered a tiny and extremely well preserved fossil in 1909, which he called Marrella.
Parks Canada offers guided hikes to three unique Burgess Shale locations in Yoho and Kootenay national parks.
Mt Stephen Trilobite Bed
Mount Stephen overlooks the town of Field, BC and the Kicking Horse Pass National Historic Site in Yoho National Park.
A short but steep hike brings you to expansive views of the valley and countless fossil specimens.
UNESCO World Heritage Designation
United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Sites are designated as having “outstanding universal value” under the Convention Concerning the Protection of the World Cultural and Natural Heritage.
UNESCO World Heritage Designation
The Burgess Shale sites in Yoho National Park were added to the UNESCO World Heritage list in 1980.
These sites now form part of the larger Canadian Rocky Mountain Parks World Heritage Site.
Stanley Glacier, Kootenay National Park
Soft-bodied fossils from the Cambrian period can be found in numerous locations around the world.
In neighboring Kootenay National Park, deposits can be found near the foot of Stanley Glacier. Parks Canada offers family friendly guided hikes to this location throughout summer.
3D image of Trilobite fossil (2021) by Matt ScobelParks Canada
Animated videos and Dawn of Life panoramic photo provide by Royal Ontario Museum - https://www.rom.on.ca/
Historic photos of Walcott Quarry provided by Smithsonian Institution Archives - http://siarchives.si.edu/
Historic photo of railway workers provided courtesy of Glenbow Archives, Archives and Special Collections, University of Calgary
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