Burgess Shale
The Burgess Shale Formation, located in the Canadian Rockies
Canadian Rockies
The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains range. They are the eastern part of the Canadian Cordillera, extending from the Interior Plains of Alberta to the Rocky Mountain Trench of British Columbia. The southern end borders Idaho and Montana of the USA...

 of British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, is one of the world's most celebrated fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 fields, and the best of its kind. It is famous for the exceptional preservation of the soft parts of its fossils. At (Middle Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...

) old it is one of the earliest fossil beds containing the imprints of soft-parts.

The rock unit is a black shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...

, and crops out at a number of localities near the town of Field
Field, British Columbia
Field is an unincorporated settlement of approximately 300 people located in the Kicking Horse River valley of southeastern British Columbia,Canada, within the confines of Yoho National Park....

 in the Yoho National Park
Yoho National Park
Yoho National Park is located in the Canadian Rocky Mountains along the western slope of the Continental Divide in southeastern British Columbia. Yoho NP is bordered by Kootenay National Park on the southern side and Banff National Park on the eastern side...

The Burgess Shale was discovered by palaeontologist Charles Walcott
Charles Doolittle Walcott
Charles Doolittle Walcott was an American invertebrate paleontologist. He became known for his discovery in 1909 of well-preserved fossils in the Burgess Shale of British Columbia, Canada.-Early life:...

 in 1909, towards the end of the season's fieldwork.