Burgess Shale

noun

1. a bed of Cambrian sedimentary rock in the Rocky Mountains in British Columbia containing many unique invertebrate fossils

Burgess Shale

/ bûr′jĭs /

1. A rock formation in the western Canadian Rockies that contains numerous fossilized invertebrates from the early Cambrian Period.

Burgess Shale

1. A famous rock formation in the western Canadian Rockies, containing unusually well-preserved fossil invertebrates of the early Cambrian Period (from about 540 million years ago). The Burgess Shale fossils provide valuable information about the evolution of early life on Earth .

Word History and Origins

Origin of Burgess Shale¹

named after the Burgess Pass, where the bed is exposed

A Closer Look

Animals in the period known as the Cambrian Explosion sported bizarre combinations of legs, spines, segments, and heads found in no present-day animals. Many of these animals became extinct, leaving no descendants, whereas others may have evolved into groups that are familiar to us today. Most of our knowledge about these early life forms comes from the Burgess Shale , a 540-million-year-old formation of black shale discovered in 1909 by Charles Walcott in the Rocky Mountains of British Columbia. The unique process of fossilization that occurred in the Burgess Shale allowed exquisite preservation of these early animals. While in most cases a reaction to oxygen causes the soft parts of animals to rot away prior to fossilization, the Burgess Shale animals were killed instantly by a mudslide deep in the ocean, where there is a lack of oxygen. After burying the animals, the mud hardened into shale, preserving the soft animal parts. At the time of his discovery, Walcott was able to classify the fossils as ancestors of modern animals. The Burgess Shale was reexamined in the mid-1960s, and many new, unknown fossils were found. When Harry Whittington, Derek Briggs, and Simon Conway Morris studied these new fossils in the 1970s and 1980s, they realized that many of them did not fit into the modern classification system. The implication that there were more basic animal forms in the Cambrian Period than there are today shook up traditional ideas about evolution. In 1989 Stephen Jay Gould brought the Burgess Shale to wide public attention with the publication of his book Wonderful Life .

Example Sentences

Only a dozen species have known complete appendages, yet most of those are preserved as highly compressed, flat fossils, as is seen in the Burgess Shale from British Columbia.

From Science Daily

The quarry is named in part after the scientist Charles D. Walcott, who discovered the enrolled trilobites there in his youth, before going on to famously discover the Burgess Shale while Director of the Smithsonian Institution.

From Science Daily

Because of the conditions in the Burgess Shale, which was likely buried rapidly in an underwater mudslide, many soft tissues like brains, eyes and digestive organs were preserved.

From Salon

The jellyfish specimens were found in the Burgess Shale, a fossil-rich site in the Canadian Rockies that provides a glimpse of life during Earth’s Cambrian explosion.

From New York Times

The researchers think that adding jellyfish to the Burgess Shale’s miniature menagerie adds another layer of complexity to Cambrian ecosystems.

From New York Times