Graptolites (Graptolita) are colonial animals. The biological affinities of the graptolites have always been debatable. Originally regarded as being related to the hydrozoans, graptolites are now considered to be related to the pterobranchs, a rare group of modern marine animals.
The graptolites are now classed as hemichordates (phylum Hemichordata), a primitive group which probably shares a common ancestry with the vertebrates.
In life, many graptolites appear to have been planktonic, drifting freely on the surface of ancient seas or attached to floating seaweed by means of a slender thread. Some forms of graptolite lived attached to the sea-floor by a root-like base. Graptolite fossils are often found in shales and slates. The deceased planktonic graptolites would sink down to and settle on the sea floor, eventually becoming entombed in the sediment and are thus well preserved.
Graptolite fossils are found flattened along the bedding plane of the rocks in which they occur. They vary in shape, but are most commonly dendritic or branching (such as Dictoyonema), saw-blade like, or "tuning fork" shaped, such as Didymograptus murchisoni.
Thursday, 20 September 2018
Monday, 17 September 2018
Sunday, 16 September 2018
Sunday, 2 September 2018
BURGESS, WALCOTT & WAVING CAMBRIAN WORMS
The fine-grained shales from the Burgess were once part of the ancient landmass known as Laurentia, the ancient geologic core of the North American continent, and are home to some of the most diverse and well-preserved fossils in the world. The sedimentary shales here contain fossils that open a window to marine life some 508 million years ago.
The site is made up of a few quarries and includes the Stephen Formation (Mount Wapta and Mount Field) and the upper Walcott quarry with its Phyllopod Bed. There is also a lower quarry named for Professor Piercy Raymond who opened the site in 1924.
It is one of the rare locations in the world where both soft tissues and hard body parts have been fossilized amidst the layers of black shale that form Fossil Ridge and the surrounding areas.
Discovered 109-years ago in 1909 by Charles D. Walcott, the site has continued to wow scientists and the community at large year after year. Charles was in Canada after losing his first wife to a train crash in Connecticut. He met Mary Morris Vaux, an amateur naturalist from a wealthy family and this new love and her interest in the wilds of Canada had brought him back.
Walcott was a geologist, paleontologist and administrator of the Smithsonian Institution in Washington, DC, USA. He was an expert in Cambrian fossils for his time. A company man, he joined the US Geological Survey in 1879 and rose to become a director in 1894. He served as President of the American Association for the Advancement of Science in 1923 and was an advisor to President Theodore Roosevelt.
Picture the world at this time. Coca-Cola sold their first soft drink, in Germany, Wilhelm Roentgen developed the first x-ray and it was a year before the United States Supreme Court ruled that "separate but equal" public facilities for whites and blacks ought to be legal.
So, up and coming Walcott was up exploring in the Rockies and stopped to rest his horse. Always a rock man, he had his hammer handy and split some likely blocks. They contained trilobites and other arthropods now famous from the site.
While he recognized the significance of the site, it wasn’t until 1960 through the work of Alberot Simonella and others that the Burgess received the scientific attention it deserved.
In 1967, Harry Whittington initiated the Cambridge Project to re-open the Burgess files and build on the work of his predecessors. He brought two grad students on board to do the heavy lifting as a means to publish or perish. Simon Conway Morris (Worms) and Derek Briggs (Arthropods) completed the trio and together they formed the foundation of what was to become some of the most significant work of our time.
Imagine the first paleontologists working on these weird and wonderful specimens. Wondering at the strange and unlikely creatures made real before their eyes. It is a rare and exquisite thing to see soft-bodied organisms fossilized.
Every year, a new species or magnificent specimen is unearthed. In 2011, a hiker discovered a rare fossil of Ovatiovemis, a genus of filter-feeding lobopodians. Picture a marine worm with nine arms waving to you. Yep, that’s him. The specimen she found is now described as Ovatiovermis cribratus and is one of only two known specimens of Oviatiovermis from the Burgess.
This important site in the Canadian Rockies has been awarded protection as a UNESCO World Heritage Site (1981) in recognition of the exceptional fossil preservation and diversity of the species found here.
With countless hours of research and study, we now know the Burgess Shale contains the best record we have of Cambrian animal fossils. It reveals the most complete record of creatures that proliferated the Earth showcasing the Cambrian explosion 545 to 525 million years ago.
It was a time of oceanic life in all it's splendor. The land may habe been inhospitable, barren and uninhabited but our oceans were teeming with new species. Great soft fine-grained mudslides slid onto an ecosystem in a deep-water basin.
Millions of years later, this unlikely event was revealed to us through the fossils preserved at Burgess.
Subscribe to:
Posts (Atom)



