The first fossil discoveries in the area of the Burgess Shale were made on Mount Stephen in the late 19th century. Exactly who made the first discovery may never be resolved … there are conflicting claims from a geologist, Richard McConnell, and an astronomer, Otto Klotz. Nevertheless, the early finds set the stage for the later discovery of the Burgess Shale.
The Trilobite Beds are named after the millions of trilobite fossils found on the slopes of Mount Stephen, about 5 km (3.1 miles) southeast of the Burgess Shale, between Wapta Mountain and Mount Field. The discovery and first descriptions of fossils from this location near the end of the 19th century played a pivotal role in attracting Charles Walcott to the area, first in 1907 and again in 1909 when he discovered the Burgess Shale.
The discoverer of the “Fossil Beds” (as they were commonly known) may never be known
A geologist for the Geological Survey of Canada (GSC) named Richard McConnell is often credited with making the first collection of fossils from this location on September 13, 1886 – after labourers working in the nearby village of Field told McConnell about “stone bugs” (trilobites) they had seen on the slopes of Mount Stephen.
Other GSC geologists had already collected fossils from Mount Stephen along the CPR construction line, but not specifically from the soon-to-be-famous beds.
Ogygopsis klotzi from the Fossil Beds and reverse of slab showing original label. © GEOLOGICAL SURVEY OF CANADA. PHOTO: JEAN-BERNARD CARON
Following McConnell’s initial visit, additional collections were made at the site by Survey geologists. The most significant of these was perhaps one made by Henri-Marc Ami five years later, in 1891.
That same year Otto Klotz, an astronomer working for the Department of the Interior along the railway at the time, acquired a separate collection from the Fossil Beds. These apparently were collected by his cook during the summer of 1886.
Ogygopsis klotzi collected by Klotz’s cook from the Fossil Beds and reverse of slab showing original label. © UNIVERSITY OF MICHIGAN MUSEUM OF PALEONTOLOGY. PHOTO: JEAN-BERNARD CARON
Klotz was using astronomical observations to determine precise longitude co-ordinates for the railway. As part of his work he also accurately determined the heights of peaks such as Mount Burgess – which he named in 1886 for Alexander MacKinnon Burgess, Deputy Minister of the Interior at the time.
Klotz, best known for becoming Canada’s first Dominion Astronomer in 1916, sent his fossil collection to Professor Carl Rominger, an acquaintance and geologist at the University of Michigan at Ann Arbor, where Klotz had graduated in 1872. (Klotz’s collection is now at the University of Michigan Museum of Paleontology.) It did not take long for Rominger to publish a cursory account of these fossils in an 1887 essay entitled “Description of primordial fossils from Mount Stephens [Mount Stephen today], N.W. Territory of Canada”. In this, he named Klotz as the discoverer of the Fossil Beds – an assertion quickly disputed by McConnell.
Fossils from Mount Stephen illustrated by Rominger (1887)
GSC Geologist Robert McConnell published his report on the trilobites in 1887, catching the attention of Charles Walcott. Walcott, who would go on to discover and name the Burgess Shale, was a prominent American geologist who had a life-long interest in trilobites. However, it would be another 20 years before he would make his first visit to the area (in 1907).
An employee of the US Geological Survey at the time, Walcott obtained specimens from both the McConnell/GSC (Geological Survey of Canada) collection and the Otto Klotz collection, finally concluding the Mount Stephen fossils were of Middle Cambrian age.
Walcott corresponded with the GSC on a regular basis at the time, helping identify many specimens (for Survey paleontologist Henri-Marc Ami, in particular) and providing his expertise on the stratigraphy of the area.
Left, fossil list from the Fossil Beds on Mount Stephen with the two right columns bearing the notations CDW (for Charles Doolittle Walcott) and HMA (for Henri-Marc Ami) dated 1892. Right, stratigraphic map on reverse showing Mount Stephen and Mount Field and sketches of fossils. © GEOLOGICAL SURVEY OF CANADA. PHOTOS: JEAN-BERNARD CARON
A few years later, even as Walcott was helping to identify the Canadian finds, several of McConnell’s and Ami’s specimens were studied by Joseph Whiteaves, the GSC‘s chief palaeontologist in Ottawa.
Anomalocaris canadensis collected by Ami from the Fossil Beds and reverse of slab showing original label. © Geological Survey of Canada. Photos: Jean-Bernard Caron
In a historically important paper published in 1892, Whiteaves described a strange Mount Stephen fossil as resembling a kind of headless shrimp with poorly preserved appendages. Because of the unusual pointed shape of the supposed ventral appendages and position of spines near the rear end of the animal, Whiteaves named it Anomalocaris canadensis. The genus name “Anomalocaris” meant “unlike other shrimps” and the species name “canadensis” referred to the country of origin.
This species represents one of the most spectacular animals from the Burgess Shale. While it is now interpreted as the largest predatory arthropod in the Cambrian seas, the story of its description is a series of misinterpretations and errors.
In 1887, following the 67th Annual Meeting of the British Association for the Advancement of Science, held in Toronto, a special cross-Canada rail excursion allowed delegates to experience the spectacular geology and palaeontology of western Canada. The trip was organized by Byron Edmund Walker, an influential Toronto banker and amateur palaeontologist — and it included a visit to the Mount Stephen Fossil Beds, where many participants, including Walker, made collections.
Walker loaned his collection of fossils from Mount Stephen to George F. Matthew, an eminent Canadian authority on Cambrian fossils
In 1899 Matthew published a paper describing and naming many new fossils from this material, including a narrow, tapered, ridged fossil he called Orthotheca corrugata, and a larger flattened tube christened Byronia annulata in honour of Walker.
The Mount Stephen Orthotheca was interpreted by Matthew as a kind of annelid worm tube, but was later recognized to be a spine (and the type specimen) of another iconic Burgess Shale animal, Wiwaxia corrugata.
In 1904, Walker donated his important fossil collection (including the Mount Stephen material) to the University of Toronto’s Geological Museum, which in 1913 became the core of the newly-founded Royal Ontario Museum of Palaeontology, under the directorship of William Arthur Parks. Walker, who had been knighted by King George V in 1910, was co-founder of the ROM and first Chair of the Board of Trustees.
The name most commonly associated with the Burgess Shale is probably Charles Doolittle Walcott (1850-1927). A specialist on Cambrian trilobites and brachiopods, he published hundreds of papers during his long and successful career. One of his greatest contributions to science came with his discovery of the Burgess Shale in 1909.
Charles Doolittle Walcott was a towering figure in the history of American science at the turn of the 20th century. He was director of the United States Geological Survey (1894-1907), Secretary of the Carnegie Institution of Washington (1902-1905), Secretary of the Smithsonian Institution (1907-1927), president of both the American Association for the Advancement of Science (1923) and the National Academy of Science (1917-1922), and even acted as a science advisor to Theodore Roosevelt.
Despite his many duties, Walcott remained an active field geologist and paleontologist until his death in 1927. He spent every field season from 1907 to 1925 working at least part of each summer in the Canadian Rockies – often accompanied by his family, including his second wife Helena (from 1907 to 1910), his third wife Mary (from 1914 to 1925), and one or more of his four children (until 1918).
Walcott’s interest in the Canadian Rockies began as early as 1886, when fossils were discovered on Mount Stephen in the Fossil Beds (now called the Trilobite Beds). He published two papers (in 1887 and 1888) based on fossils from this locality that had been sent to him by colleagues.
Walcott finally managed to visit the Trilobite Beds in the summer of 1907, but only for a short time. His main aim during the five-week field season was geological: to study the broader stratigraphy of various Cambrian sections in the area, including on Mount Stephen. Walcott spent only one day (Sept. 4th) at the Fossil Beds. Part of his research for that year was published in the scientific section of the Canadian Alpine Journal in 1908 (a publication of the newly-established Alpine Club of Canada).
This publication was the first illustrated account of most of the fossils found at the locality. In it, Walcott proposed the term “Ogygopsis shale” after the dominant form of trilobites found there. (The term is still sometimes used today in the technical literature to refer to the Trilobite Beds.)
“The best way to make a collection from the ‘fossil bed’ is to ride up the trail on a pony to about 2000 feet [about 600 m] above the railroad, collect specimens, securely wrap them in paper, place them in a bag, tie the bag to the saddle, and lead the pony down the mountain. A fine lot can be secured in a long day’s trip, 6 a.m. to 6 p.m.”
At the time, this article would have been widely read by tourists visiting the area, probably encouraging private collectors and visits to the site. (Note: Do not attempt to follow Walcott’s advice today! Collecting fossils from the area is not allowed without a research and collecting permit).
Tourists arriving by train would have stayed at the comfortable Mount Stephen House in Field, just below the fossil locality. “All enjoyed the home-like Mount Stephen House” Walcott wrote on Aug 25th 1907. Walcott and his family continued to stay at the hotel in the following years when they did not camp closer to the fossils.
Walcott also introduced the term “Stephen Formation” (in a different publication, also published in 1908) as a unit of Cambrian rock which included what he had defined as the “Ogygopsis shale.”
The Walcott family returned to the Canadian Rockies in 1909 to continue exploring the Stephen Formation and to search for more of the “Ogygopsis shale” on nearby mountains.
On Aug. 30th, almost at the end of his field season, Walcott was riding alone between Wapta Mountain and Mount Field, just a few kilometers north of Mount Stephen, on a trail still used to reach the area, when he stumbled on “many interesting fossils”. This was a day after he had discovered more “Ogygopsis shale” nearby, according to his field notebook (though not a single specimen of Ogygopsis would ever be found there).
He returned the next day accompanied by his wife Helena and his son Stuart. Together they found several other remarkable fossils that Walcott immediately sketched in his field notebook. Obviously impressed by this discovery, Walcott’s entry for Aug. 31st – Sept 1st reads:
“Out with Helena, Stuart collecting fossils from the Stephen Formation. We found a remarkable group of Phyllopod crustaceans – Took a large number of fine specimens to camp.” The next day: “We continued collecting found a fine group of sponges on slope (in-situ) – Beautiful warm days”
The fossils discovered by the Walcotts represented types of animals that had never been seen before.
The Walcotts spent a total of five days that year collecting fossils in the area, mostly from loose slabs of rock found near the trail and on slopes.
Walcott quickly realized the importance of his finds. In a letter sent later that year to William Arthur Parks (his colleague and long-term correspondent at the University of Toronto) Walcott wrote: “…I had a few days collecting in the Stephen Formation [today’s Burgess Shale] in the vicinity of Field in September, and found some very interesting things.”
Charles, Helena and three of their children (Helen, Stuart and Sidney), as well as Walcott’s long term field camp cook, Arthur Brown, returned to the area the following year (1910). They all camped below Burgess Pass near the 1909 discovery site, a site which they would use year after year. Travelling by railroad and horse, as well as living in the camp and collecting Burgess Shale fossils would become a familiar summer occupation for the Walcotts in the coming years.
On Aug. 2nd he wrote: “Out collecting with Helena, Stuart and Sidney. We found a fine bed of ‘Lace crab’ [Marrella] plus various odd kinds of things.” They had finally located the source of the fossils in its proper stratigraphic context – i.e., within the rock beds rather than scattered about in loose rocks that had slid down onto the trail.
From that day on, most fossils would be quarried from several layers within a section two metres (six feet) thick that Walcott subsequently referred to as the “Phyllopod bed.” (The name came from the presence of arthropod fossils with finely preserved leaf-like appendages, like Waptia.
Walcott and his team initially dug a small quarry, which would grow much larger over the coming years. (The location is now known as the Walcott Quarry, and the area separating Wapta Mountain from Mount Field is informally known as Fossil Ridge.)
Excavated blocks of shale had to be slid down the side of the mountain and then transported by horse to camp, where the shale was split, trimmed, and packed. Fossils were then sent to Field and shipped by train to Washington, D.C.
1911 marked the first time Walcott had a chance to publish his findings from the “Burgess Shale”. In a paper on holothurians and medusae Walcott proposed the name Burgess Shale as “a geographic name for a shale to which the term of Ogygopsis shale [=Mount Stephen Trilobite Beds] was given in 1908. It is proposed to call it the Burgess shale of the Stephen formation”.
Walcott named one of the most spectacular fossils Sidneyia inexpectans, meaning “Sidney’s discovery”, as it was discovered in 1910 by his son Sidney. This became one of the first animals from the Burgess Shale to be described and illustrated. The first reconstruction of this animal appeared in The Ottawa Naturalist in 1917, but proved to be misleading.
In addition to his technical accounts, Walcott also wrote a popular article for National Geographic in June 1911 called “A Geologist’s Paradise”, describing the scenic beauty of the region. The Burgess Shale became an instant sensation, quickly spreading beyond conventional scientific circles.
1911 also marked the tragic death of Walcott’s wife Helena in a train crash on July 11th. (Walcott would later marry the prominent naturalist Mary Vaux in 1914.) Despite his loss, and perhaps to bury his grief in work, Walcott returned to the site with his family in August.
His team spent five weeks digging for fossils, occasionally using explosives to blast through the rock. At the end of the season the quarry was about 20 m (66 feet) wide and 3 m (10 feet) deep with a back wall about 3.5 m (11 feet) tall. As in 1910, huge blocks of shale were brought to camp to be split, trimmed, and packed.
Walcott returned again in 1912, 1913, and 1917, collecting more specimens and further extending the quarry, but fewer and fewer new species were found.
Walcott had suggested as early as 1912 that the base of his quarry was unsuitable for fossils, writing “The layers of shale are arenaceous, irregular, and not favorable for preserving fossils.” In a report published in 1918 he reflected on his 1917 quarrying activities: “this practically exhausts a quarry which has given the finest and largest series of Middle Cambrian fossils yet discovered and the finest invertebrate fossils yet found in any formation in any country.”
Walcott made only short collecting trips after 1917, returning in 1919, 1921, and 1924, collecting fossils from loose material below the quarry on talus slope. The day of his last visit to the quarry (July 11th, 1924) he wrote: “We went up to my old fossil quarry and collected 2 packages of fossils from rock quarried in 1919. Nothing new but all good for exchange.”
During Walcott’s last summer at the quarry (1924), Percy Raymond of Harvard University made his first visit to the site while leading a summer school course in field geology. Raymond never met Walcott in the field but would soon return to the quarry with more ambitious goals.
Over the course of his many visits to the area, Walcott collected some 65,000 fossils. This collection became one of the jewels of the Smithsonian Institution’s permanent collections at the US National Museum (now the National Museum of Natural History in Washington D.C.).
Specimens received from the field after each of Walcott’s collecting seasons were trimmed at the Smithsonian Institution using a rocksaw to remove as much of the surrounding shale as possible. This would have minimized the weight and volume of rock that had to be stored. Catalogue numbers and small, green, diamond-shaped labels were applied to the specimens (35k for the Walcott Quarry specimens and 35k/10 for specimens collected above it – probably representing the level of the Raymond Quarry).
Specimens were then neatly arranged in trays and organized in successive drawers according to their taxonomic group. Species would be arranged in alphabetical order within phyla, so a specimen of Marrella splendens, for example, would have been placed in alphabetical sequence with other arthropods.
When a single slab of rock was collected with several species visible, each specimen would have been cut out of the larger slab, and the various individual fossils separated and organized in different drawers by species. During this process, parts and counterparts of the same specimens were not kept together and were often dispersed through various areas of the collections.
Walcott also sent duplicates of some of his fossils to other museums (often the counterparts) as exchange material, so parts and counterparts of the same specimens (including figured specimens) sometimes ended up in different collections.
After Walcott’s death in 1927, his fossils would be largely ignored for nearly 40 years. It was not until 1962 that Alberto Simonetta and Laura Delle Cave published several scientific papers presenting a number of reconstructions of the fossil arthropods. (With a few exceptions, Walcott did not include re-creations of his fossils.) These studies were preliminary and the Walcott collection remained unused until Harry Whittington and his team re-investigated Walcott’s collection, along with collections subsequently made by Raymond, and the Geological Survey of Canada.
Even though Walcott observed in the field that some specimens came from particular layers within the Phyllopod Bed, he never recorded the exact stratigraphic origin of his specimens. For this reason, the Smithsonian collection represents a mix of fossils from different layers representing different time periods. The lack of detailed stratigraphic information was one justification for subsequent Geological Survey of Canada and Royal Ontario Museum expeditions.
Today the Walcott collection at the National Museum of Natural History remains a critical reference for the Burgess Shale because it hosts most of the type specimens that were used to describe the majority of species recovered from this site.
The collection also continues to provide important new discoveries, mainly from the non-type and non-figured specimens (those specimens that have not been described in print, representing the vast majority of the collection).
For example, two specimens which had clearly been set aside and photographed by Walcott for publication (but for some reason were never included in any of his papers) turned out to belong to a new species. In 2007 the two specimens were used in a publication – together with newly-collected specimens from the Royal Ontario Museum – and the species was named Orthrozanclus reburrus. This suggests more new species could still be awaiting discovery in Walcott’s collection, decades after they were unearthed!
The following objects were discovered by the Royal Ontario Museum during various expeditions to the Burgess Shale starting in 1975. They were found in Walcott’s camp below Burgess Pass, about one kilometre (0.6 miles) south from the main Burgess Shale quarry. Rusty cans and tinware are still visible today in several areas of his camp, as well as beds made of now rotting cedar boughs and piles of leftover pieces of shale (from blocks that were brought to the camp to be split and checked for fossils). Many fossils, including Marrella splendens, were found by ROM crews in these debris piles.
The McClary Company of London, Ontario offered a range of camping supplies. Walcott may have purchased field equipment from either the Toronto or Winnipeg outlets when he travelled to the Burgess Shale across Canada by train.
Practical Items from Walcott’s 1910 Campsite – all manufactured in the early 20th century
These objects were found by ROM crews in 1994 and 1995 when they were removing the piles of debris that had accumulated since Walcott last worked the quarry in 1917. These objects provide important clues to early 20th-century techniques employed by Walcott for extracting large blocks of shale and fossils.
These newspapers were found frozen in a block of ice in 1995 by a ROM crew digging at the debris that had fallen into the Walcott Quarry. Newspapers were used to pack fossil specimens, and these were left behind after Walcott’s 1917 field season. (The cartoon on the front page represents Theodore Roosevelt.)
Hitting the wedge with heavy hammers and rotating it regularly would have had the same effect as a pneumatic or gasoline rock drill. But it would have required a great deal of effort to make a hole large enough for a stick of dynamite. (Some pitting from dynamite explosions is still visible in the back wall of the quarry.)
Chisels like this were used to carefully split shale in the search for fossils. This one was probably left behind because the flat tip had broken against the hard shale.
Such triple-digit gloves provided warmth and a comfortable grip in all seasons. The leather is thick and was probably sufficient for protection against the sharp edges of the shale during quarrying and collecting operations.
Faced with the huge task of describing the many new animal and algal forms he collected during his excavations, Walcott opted to publish short descriptions of many fossils in a series of monographs that he himself considered preliminary works.
He published his work in various volumes of the Smithsonian Miscellaneous Collections series (not surprisingly, as Walcott was Secretary of the Smithsonian at the time). These monographs remain invaluable reference works and are still the only source of information for some taxa.
It is worth emphasizing that most of Walcott’s publications were based on material that had been collected in his earlier expeditions, especially during his 1910 and 1911 field seasons. With a few notable exceptions, fossils discovered in later years were not described in print.
In 1911 he published three monographs, based mostly on material he collected during his 1910 field season. These described arthropods (“Merostomata” including Sidneyia), holothurians and medusae, and annelid worms.
Walcott published a larger study on the arthropods in 1912, including Marrella, Waptia, and Naraoia (the first fossils he discovered in 1909). This was followed by monographs on trilobites (1918), algae (1919), and sponges (1920). Many more specimens were described in a final, posthumous monograph (edited by Charles Resser) published in 1931.
Walcott named more than 60 new genera and many new families that he placed within established orders and classes. In addition to these named specimens, Walcott recognized many other new forms which were neatly organized in his collections (sometimes with suggested new names on small note cards), but he did not have time to describe all of them during his lifetime.
Walcott had to provide new names for both the genus and the species of his many fossil discoveries. He would often turn to the natural features in the area (mountains, peaks, glaciers, valleys, waterfalls, lakes, passes, creeks) for the name of a new genus. Most of these features had been named during the late 19th century by explorers and early surveyors. (Otto Klotz, for example, named Mount Burgess in 1886 after the Deputy Minister of the Interior Alexander Burgess.)
Some of the local names Walcott chose were based on Stony or Cree Indian words, such as Waptia (from “Wapta” meaning river), Takakkawia (from “Takakkawa” meaning magnificent), and Yohoia (from “Yoho” representing a cry of astonishment).
Names of other genera were chosen from personal names (Sidneyia for his son Sidney, Marrella for his friend John Edmund Marr from Cambridge University), general geographic names (Canadia and Canadaspis), towns (Banffia and Laggania – after the hamlet of Laggan, now Lake Louise) or railway points (Eldonia and Leanchoilia). Species names were mostly based on descriptive terms such as compacta, elongata, perfecta, or triangulata.
Walcott used photography to document his scientific work.
In the field he used various cameras including a Cirkut Camera to produce stunning panoramic images. Many of these images were then published in scientific or popular accounts.
Walcott’s 1911 article in National Geographic called “A Geologist’s Paradise” included a supplement featuring several images including one of his panoramic images of the area. The image folded out to a size of 2.5m (8 feet), making it the single largest photograph ever included in the magazine. (See cover of the 1911 article in the section “Triumph & Tragedy: 1911” and Walcott’s panorama in the section “The Great Discovery: 1909”)
Walcott used a series of photographs to illustrate his work back in Washington, but because it was difficult to obtain good images of the fossils, he modified many photos for publication (see Orthrozanclus below).
Such modifications were a common practice at the time to enhance features that were difficult to show using contemporary photographic techniques. But they would not be acceptable for scientific publication today because they can sometimes add subjective features that are not present on the specimens.
The landmark discoveries and extensive field work of Charles Walcott were followed up immediately by the research of another American palaeontologist, Percy Raymond. He visited the Burgess Shale three times in the mid-1920s, opened a new quarry in 1930, and established a substantial research and teaching collection at Harvard University.
By the middle of the 1920s, Walcott’s discovery of the Burgess Shale was already well known to the scientific community and the wider public. The proximity of a Parks Canada trail (which undoubtedly had facilitated Walcott’s discovery) made the Burgess Shale an attractive destination for tourists, teachers, and students. This trail, originally established in the early 20th century, is still being used today.
Amongst the many new visitors to the site was Percy Raymond, a curator of Paleontology at Harvard’s Museum of Comparative Zoology. Raymond had been assistant curator at the Carnegie Museum (1904-1910) and the Geological Survey of Canada’s chief paleontologist (1910-1912) before moving to Harvard where he worked until his retirement in 1945.
Perhaps more importantly, Raymond noted the presence of a second fossiliferous bed higher up on the mountain, about 22 metres (72 feet) above the Walcott Quarry. Raymond was not the actual discoverer of these fossiliferous beds – Walcott had collected several fossils from there (and even sketched some), like the sponge Vauxia. But Raymond quarried these beds more extensively, uncovering additional Vauxia specimens as well as Ottoia, Leanchoilia, and Sidneyia. This second quarry is now known as Raymond’s Quarry — but the limits of the original quarry have been lost due to subsequent excavations by the GSC and ROM at the same levels.
Raymond’s specimens showed Burgess Shale-type fossils could be found beyond the famous Walcott Quarry and at various stratigraphic intervals, including in the Mount Stephen Trilobite Beds. Indeed, new Burgess shale-type deposits have since been discovered as far away as China, Greenland, and Australia.
The next scientifically-significant visitor to the Burgess Shale was a famous physicist turned paleontologist. Franco Rasetti had immigrated to Canada from Italy in 1939 to take the chair in Physics at Laval University, Quebec. Rasetti had been part of an influential group of scientists headed by Enrico Fermi before the Second World War and helped work out the basics of atomic fission. Fermi went on to help develop the first atomic bomb, but Rasetti chose to take a job at Laval in Quebec because he did not want to be involved in war-related research. Even as he helped establish Laval’s Physics Department, he became increasingly interested in botany and paleontology, particularly trilobites. A former student recalled that Rasetti looked for trilobite fossils “everywhere”, collecting thousands of specimens which he carefully classified and described.
During two field expeditions in 1947 and 1948, Rasetti systematically collected many trilobites from the Stephen Formation and other Middle Cambrian rocks in the southern Canadian Rockies. His accounts of these trilobites were published in the Smithsonian Miscellaneous Collections in 1951 and still represent the only major regional reference on these fossils.
Trilobites are valuable to paleontologists because they are good biostratigraphic indicators: they tend to be common fossils, to be distributed widely and to evolve comparatively quickly. Using trilobites as markers allows researchers to determine that different rock units, even if they are widely separated from each other, have a similar age if they have a similar combination of trilobite species.
Prior to Rasetti’s work, Deiss (1939) had proposed the Bathyuriscus–Elrathina Zone, named after two trilobites found in Middle Cambrian rock units present in North America. These trilobites are common in the Burgess Shale, placing the relative age of the Stephen Formation in the Middle Cambrian. Rasetti established a number of additional trilobite zones and “faunules” subdividing the Stephen Formation into smaller relative time slices, which proved useful in later stratigraphic studies.
During the early 1960s, the GSC was actively involved in re-mapping the southern Rocky Mountains of Alberta and British Columbia using new methods and techniques. Harry Whittington, then Professor of Geology at Harvard University, contacted the GSC with a proposal to reinvestigate the Burgess Shale and reopen the Burgess Shale quarries. The proposal was soon expanded into a detailed paleontological, geological, and stratigraphic study of the Burgess Shale.
As he made his first studies, Whittington discovered the fossils were not two-dimensional impressions (as Walcott had thought). In fact, they retained some of the original organism’s three-dimensional structure, albeit highly compressed into very thin layers within the rock. This observation meant that when split open, the part and counterpart (opposing sides) of the same fossil could reveal minutely different levels of the specimen — and these needed to be studied together to provide a complete anatomical interpretation.
Before the GSC collections, specimens from various layers had been collected and stored together, so very little information on the exact stratigraphic location of the fossils was available. In addition, the parts and counterparts of specimens collected by earlier expeditions had often been dispersed to different collections, making it difficult to reliably estimate the number of specimens present (and sometimes removing important morphological information which would have only been available with both sides of the fossil).
The specimens collected in 1966 and 1967 by the GSC would attempt to address these problems.
In 1966 the Survey’s James Aitken (an expert on stratigraphy) led a party of thirteen, including Whittington and William Fritz (a GSC stratigrapher and expert on Cambrian trilobites). (David Bruton from the University of Oslo would join the 1967 field season.)
As the excavation continued, the exact level at which each fossil was found was measured from a fixed reference point and great care was taken to ensure parts and counterparts of specimens were kept together. This precise methodology was a significant improvement on earlier expeditions.
Whittington was the first scientist to prepare fossils from the Burgess Shale anatomically, very similar to the dissection of a modern organism.
After mechanical preparation, the next step was to draw specimens using a camera-lucida attachment (a drawing tube with a mirror attached to a stereomicroscope). This allowed an observer to see both the fossil and its image reflected onto a sheet of paper for easy tracing of details. The method allowed researchers to identify fine differences in the different layers of the fossils and to interpret the features observed. Both preparation and drawing methods are still used today to study Burgess Shale fossils.
The Cambridge group consisted of Harry Whittington and two of his former PhD students, Derek Briggs (who studied the fossil arthropods of the Burgess Shale) and Simon Conway Morris (who was assigned the fossil worms). Chris Hughes and David Bruton (the latter being the only member of this group who was not based in Cambridge) provided more modest contributions on the arthropods.
In addition to the paleontological discoveries about the Burgess Shale fauna coming from the Cambridge group, the GSC‘s geological studies produced important results as well.
Olenoides, Nathorstia (2)
Bruton and Whittington
Whittington and Briggs
Conway Morris tabulated every specimen on all the slabs in the Walcott and GSC collections from the Walcott Quarry that he could find. Before this painstaking survey, nobody had any idea how big the Walcott collection actually was. The numbers were astonishing: 35,520 slabs observed, 73,300 specimens counted. Of these, about 65,000 specimens had been collected by Walcott, the rest were collected by the GSC expeditions of 1966 and 1967. (The Walcott collection represented by far the largest collection of fossils from the Burgess Shale until it was surpassed by the ROM‘s own Burgess Shale collection at the end of the 1990s.
In addition to revealing the importance of predation in the Burgess Shale ecosystem, Conway Morris suggested the structure of the Burgess Shale community was typical of what other marine communities in similar environments during the Middle Cambrian would have looked like. This conclusion was soon confirmed with the discovery of other deposits of Burgess Shale-type fossils. Conway Morris’s study also emphasized that without the exceptional preservation of soft tissues found in the Burgess Shale, about 86% of the genera (representing the majority of the specimens) in this community would have been lost to decay and left no trace in the fossil record.
The work of the Cambridge group played a critical role in re-igniting interest in the Burgess Shale and soon led to further discoveries elsewhere — notably in China. One of the main surprises the Cambridge group encountered was the fact that many organisms from the Burgess Shale did not fit easily into modern groups of animals. These studies dramatically emphasized the rapid appearance and diversity of animals during the Cambrian, and were pointed to as evidence for the “Cambrian explosion“.
The work of the Cambridge group reached a much larger audience in 1989 with the publication of Stephen Jay Gould’s best-selling book, Wonderful Life: The Burgess Shale and the Nature of History.
Gould’s main hypothesis was the possibility that many Burgess Shale organisms described by the Cambridge group represented potential new phyla, which he evocatively called “weird wonders”. This suggested that the diversity of phyla was greater in the Cambrian than it is today. Over the course of history, chance alone would have wiped out most groups, leaving a lucky few to evolve to the present.
After travelling to Cambridge for study in the 1970s, the new GSC specimens were housed at the GSC in Ottawa. They are the second-largest collection of Burgess Shale fossils in Canada, after the ROM. They reside close to older collections, principally from Mount Stephen, made decades earlier by McConnell and several other geologists from the GSC.
In 1975, the Royal Ontario Museum became the fourth major institution to conduct active field work and research on the Burgess Shale. That 1975 season marked the beginning of the most extensive campaigns of field work in the history of the Burgess Shale, dwarfing all previous expeditions combined – not only in the number of field seasons and total number of days spent in the field, but also in the discovery of new fossil sites and the number of specimens collected.
The result of those expeditions is the ROM‘s mammoth collection of more than 150,000 Burgess Shale fossils encompassing about 200 described species. Most of these fossils were collected layer by layer in several quarries in the area between Wapta Mountain and Mount Field (informally known today as Fossil Ridge). Others came from localities tens of kilometres away from the type localities. These specimens, carefully stored and catalogued, represent a treasure trove for scientists and provide material for research projects ranging from taphonomy (i.e., preservation of fossils) and taxonomy (i.e., description of new species or revision of others) to evolutionary biology, as well as paleoecological and paleoenvironmental studies.
Research on the Burgess Shale continues today, with many exciting discoveries coming both from the field and the study of the existing collections.
Desmond Collins, who left the Natural History Museum in London to join the ROM in 1968, led the first eighteen ROM field expeditions (between 1975 and 2000) – following in the tradition of the Smithsonian Institution (1909-1924), Harvard University (1930), and the Geological Survey of Canada (1966-1967). Collins had no idea in 1975 that this first expedition would not only radically transform his career, but greatly expand our knowledge of Cambrian life. When he began, Collins had no previous experience in the study of Burgess Shale fossils: his first visit to the site was a matter of serendipity.
Desmond Collins first visited the Walcott Quarry in 1972 during a one-day field excursion, part of the International Geological Congress held that year in Montreal. The excursion included Harry Whittington, James Aitken, and William Fritz – three key members of the previous GSC (Geological Survey of Canada) expeditions to the site in 1966-1967. During this short visit, Collins (whose area of expertise at the time was fossil cephalopods) was particularly impressed by the sheer number of fossils still scattered along the talus slopes after previous expeditions to the two existing quarries on Fossil Ridge (the Raymond Quarry and Walcott Quarry).
Goal: Display Specimens for Canada
Collins’ first visit also happened to coincide with a planned new gallery on Invertebrate Paleontology at the Royal Ontario Museum (a gallery that opened in 1977, but has since been replaced). He quickly realized the potential the discarded fossils from the Burgess Shale represented for the new gallery. The few specimens from the Walcott Quarry in the ROM collection at the time had been sent to the museum by Walcott himself decades earlier, but were not particularly suitable for an exhibit.
One of the arguments Collins made in favour of the first ROM collecting expedition was the fact that, in the early 1970s, there was no permanent display of Burgess Shale fossils in Canada. Today, the Royal Ontario Museum has the world’s largest collection of Burgess Shale fossils with more than 150,000 specimens. But Collins had no plan to study the Burgess Shale in depth when he formally approached Parks Canada for permission to collect fossils for display … that would only come later.
Despite several requests from Desmond Collins, Parks Canada refused to allow excavations in 1975. Instead, the nine members of the ROM team would only be allowed to collect loose rocks (talus) below the Walcott and Raymond Quarries. Many of these rocks were chunks of shale that had been dug out and discarded by earlier expeditions. In addition to specimens for an upcoming ROM gallery, Parks Canada requested that the ROM team collect duplicates of common species to be used in teaching at universities and museums across Canada (including for Parks Canada itself).
Despite poor weather conditions and the prohibition against excavations, the ROM team collected more than 8,000 fossils over eight weeks in the field. Most came from talus slopes below the Walcott Quarry and a smaller collection came from the Trilobite Beds on Mount Stephen. But the ROM team also discovered many specimens of the small arthropod Marrella splendens in Walcott’s camp just below Burgess Pass. These fossils were found in piles of split shale that had been left behind in the camp.
The team also discovered a number of artifacts (tinware, bottles) left at the camp by Walcott at the end of his expeditions.
Back in Toronto, technician David Rudkin faced the daunting task of creating sets of duplicate specimens to be distributed to museums and universities – while keeping enough good display specimens for the ROM gallery. The ROM would send about 2,000 fossils from the 1975 collection (representing dozens of species) to more than 20 institutions across Canada. Perhaps more importantly, these early collections helped shift the focus of subsequent expeditions to new research.
Discovery of New Species
Many surprises awaited the ROM crew in 1975. While scouring the slopes they found a new species, quickly dubbed the “goose barnacle” (eventually described by Collins and Rudkin as Priscansermarinus barnetti). The team also uncovered counterparts of specimens that had been collected by earlier expeditions, including a specimen of Branchiocaris pretiosa (which turned out to match a fossil that had been collected by Percy Raymond in 1930, 45 years earlier!). The Cambridge group took advantage of the 1975 collection, including several ROM specimens in their publications.
The finding of a few rare and new fossils (including some from above the Raymond and Walcott Quarries) indicated there could be entirely new fossil layers waiting to be excavated – a prediction confirmed just a few years later. Taken together, all these discoveries demonstrated new field work and collections in the area could still produce valuable research material.
Starting in 1981 and for a total of six field seasons (1981-1984, 1988, 1989), the main goal of the ROM Burgess Shale parties was finding new Burgess Shale sites in the Stephen Formation. During the early stages (particularly 1981-1982) few fossils were collected, but the rate of discovery would increase in the following years, thanks largely to excavations of the new sites.
Key Geological Studies
The ROM parties were inspired by the detailed geological work of Ian McIlreath, who had been working on his Ph.D. at the University of Calgary on rock formations related to the Burgess Shale in the mid 1970s. McIlreath had made a key discovery. He recognized that the submarine cliff adjacent to the Walcott and Raymond Quarries on Fossil Ridge (defined by Fritz in 1966 and originally spotted by Ney in 1954 on Mount Field) persisted for more than 20 kilometres (12.4 miles), running through several mountains across Yoho National Park in a roughly northwest-southeast direction. If the submarine cliff (referred to as the Cathedral Escarpment) was important in the formation and preservation of Burgess Shale fossils in the adjacent basinal Stephen Formation (as suggested by earlier GSC studies), then more discoveries were probably waiting to be made elsewhere along it.
Discovery of New Sites
The ROM crew’s discovery of rare fossils above the Walcott and Raymond Quarries in 1975 suggested there should be more fossil deposits present somewhere in the area. But Parks Canada would not allow any new excavations above the fossil localities prior to 1984. In 1981 Collins was accompanied by Derek Briggs (who returned in 1982) and Simon Conway Morris. (Both researchers had just completed their doctoral studies on the Burgess Shale fossils.)
Following the contours of the Cathedral Escarpment led to the discovery of more than a dozen new Burgess Shale-type deposits on six different mountains around the original quarries. These were among the most significant discoveries since Walcott’s time, and led to a summary paper in Science in 1983.
In most cases, only a few fossils were collected from each location, and only from talus material, so the stratigraphic origin of the fossils was difficult to determine. But at a few sites, fossils were also extracted from in-situ layers of rock, giving a better understanding of their stratigraphic relationship to the rock layers at the other sites.
Some of the new localities came from rock layers that were older than the rocks of the original Walcott Quarry, while other localities came from rock layers that were younger (see How Old is the Burgess Shale). This suggested the Burgess Shale biota not only spread out over a broad area, but also survived over a longer time span than originally thought.
Two of the new sites discovered by the ROM during these reconnaissance years were particularly remarkable and would be extensively excavated in coming years.
The Sanctacaris Locality on Mount Stephen
One of the first new localities discovered in 1981 was on Mount Stephen not too far from the Trilobite Beds featuring spectacular new specimens of Branchiocaris. It was originally dubbed W.S. for “West Stephen” but is now known as the Collins Quarry on Mount Stephen.
In 1982 the ROM parties started to excavate blocks of rock from this site, providing many specimens of Alalcomenaeus and Branchiocaris as well as new animals, such as the ctenophore Xanioascus. (Alalcomenaeus and Branchiocaris are very rare in the Walcott and Raymond Quarries but proved surprisingly abundant in the Collins Quarry on Mount Stephen.)
The first significant excavation of this new site took place in 1983. Because of the steep location, a helicopter had to airlift wooden platforms for tents to the site of the base camp. Out of the remarkable fossils discovered at the locality, one arthropod was perhaps the most striking. Originally thought to be a possible distant relative of modern spiders, it was quickly nicknamed “Santa Claws” (now known as Sanctacaris) for its many pairs of spined appendages.
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Above Walcott and Raymond Quarries
Fossil specimens were collected from talus material in 1982, 65 metres (213 feet) above the Walcott Quarry, but the source of those fossils would not be discovered for two more years.
The 1984 field season included more reconnaissance work, but the highlight of that summer was the excavation of fossils above the Raymond Quarry. The ROM crew camped in the Walcott Quarry, pitching tents on top of the snow that had accumulated within the quarry, and using the snow for drinking water and to preserve food (a practice followed in subsequent years). But the Quarry proved a precarious spot to spend the night! Rocks kept sliding down the side of the mountain (sometimes dislodged from the new excavations up the slope or jostled loose by passing mountain goats) and crashing into the tents in the quarry below. Excavations from this locality continued for another eight weeks in 1988.
During these two field seasons (1984 and 1988), two quarries were started at two different levels separated by a stratigraphic interval of about 5 metres (16.4 feet). The quarries were given ROM field names “EZ” and “UE” for Ehmaniella Zone and Upper Ehmaniella, named for the abundant trilobite present in both localities. “UE” was the higher and became the larger of the two quarries. (Both are now referred to as the Collins Quarry on Fossil Ridge.) They became a valuable source for new specimens of previously rare animals – a critical resource for researchers as they started reinvestigating these animals.
Among many other finds, the two new quarries yielded abundant specimens of:
Improved Collecting Methods
Within a period of 10 years the ROM teams collected specimens with the same techniques as previous Geological Survey of Canada (GSC) excavations — using hammers and chisels to split the small blocks of shale. Large blocks were often extracted by drilling a series of holes, inserting feathers and wedges into the holes, and then pounding the wedges into place with sledge hammers, thus creating enough stress to open up fissures in the rock. (Drill marks from the GSC and ROM excavations can still be seen in the quarry today.)
Unlike previous excavations on Fossil Ridge (by Walcott and Raymond), the ROM crews took great care to record the exact layers from which each specimen was collected. This was also an improvement over the previous GSC collecting methods, which consisted of recording the location where fossils were found measured from particular intervals. Each GSC interval usually represented various layers, so it was impossible to relate a specimen to a particular layer.
Knowing the precise levels at which the specimens were collected has allowed detailed taphonomic and paleoecological studies that were impossible using previous collections.
The Collins Quarry
The 1990 ROM expedition was much larger than in previous years, kicking off a decade of extensive digs. (The only exception was 1996, which was dedicated partially to reconnaissance.) Large crews worked the sites for up to two months each summer, with additional grants from National Geographic and Parks Canada supplementing the funding provided by the ROM since 1975.
In addition to continuing excavation in the Collins Quarry on Fossil Ridge (previously known as UE and EZ), a particularly rich layer of Tuzoia specimens was discovered between the Collins and Raymond Quarries – something hoped for since the 1975 expedition. This discovery further demonstrated that Burgess Shale fossils occur through almost the entire Stephen Formation succession on Fossil Ridge, but with very different compositions of fossils in different layers.
In 1990 the ROM crews also began to host official guided tours of the localities as part of an agreement with Parks Canada. (Guided tours of the area are still available from Parks Canada). Because of dangerous rock falls in previous seasons the ROM crew moved its campsite out of the Walcott Quarry in 1990 to a more secure meadow near the base of Fossil Ridge. This was the same campsite used by the GSC during the 1966-1967 expeditions, and by the first ROM crew in 1975.
Reopening of the Raymond Quarry
From 1991 to 1993 (and again during part of 1997) the major goal was re-excavating layers at the level of the original Raymond Quarry, which proved to be far more productive than the layers above in the Collins Quarry. The ROM started several excavations northwest and southeast of Raymond’s original quarry and after a few years of excavations, the three small quarries merged into one large quarry. As was the case for all previous excavations, the work was done mainly by hand — using sledge hammers and chisels to split the rock (with occasional recourse to rock saws and a gas-driven jackhammer-drill).
But the research highlight of 1991 was almost certainly the discovery of the most complete Anomalocaris specimen ever found. This was duly (if modestly) referenced in Collins’ field notes:
“Aug 27 (Tues) Crew up in quarry by 10. Catalogue large slabs. Parks tour including Bruce Runnegar arrives at 2. Catalogue now up to 1415 – whole Anomolocaris canadensis.”
While the nature of this species as a predator had been determined earlier by Whittington, the quality of the complete specimen (as well as additional ones collected by the ROM) provided new anatomical details and previously-unknown morphological features, confirming its status as a large, swimming predator.
Reopening the Walcott Quarry
After nearly two decades of searching for new sites, scouring talus slopes on different mountains through Yoho and Kootenay National Parks, and excavating new fossil layers closer and closer to the Walcott Quarry, the ROM team was given permission to re-open the famous site. In 1994 and 1995 the ROM team turned almost all its resources to the Walcott Quarry, where major excavations would not end until 2000. This latest phase had started with trial pits dug in 1992 (and again in 1993) below the original Walcott Quarry floor. The ROM crews were astonished to find very fine, soft-bodied fossils in layers that Walcott had rejected almost 80 years earlier as incapable of preserving fossils. (ROM crews had spent several seasons camping in this quarry, little realizing as they spread out their bedding that they were sleeping on a cache of valuable fossils.)
Before reaching these new levels, the task ahead of the ROM crew at the beginning of the 1994 field season seemed nearly insurmountable. First, the huge quantity of snow accumulated in the Quarry during the past winter had to be shoveled away. When the team arrived at the site in early July, they found three distinct patches of snow filling the Walcott Quarry, the Raymond Quarry, and the Collins Quarry. (Ironically, it was the excavations from previous years that led to the problem as the deep holes proved ideal for keeping the snow frozen, even in the middle of summer.) Once the snow was removed, the heavy work began. With a team of eight, it took the better part of both collecting seasons (two months in total) just to remove the rock debris that had accumulated since Walcott’s time.
The work was split between removing the debris and quarrying the floor of the Walcott Quarry in search of fossils. During the clean-up, the ROM team uncovered rusted tools and a frozen block of newspapers dating from 1913 to 1917 (which Walcott had apparently brought to the area for wrapping fossils.)
The effort paid off, and in the remainder of the collecting seasons, with the team carefully collecting fossils layer by layer, they recovered at least 10,000 specimens from just two rock layers located approximately 1.2 and 1.3 meters (4 feet) below Walcott’s Quarry. As was the case in the rest of the Phyllopod Bed, Marrella splendens was the most common fossil, but there were also many specimens of previously rare species including Pikaia gracilens and Hallucigenia sparsa.
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