Burgess Shale

First Glimpse of the Cambrian Explosion

The Burgess Shale is a very famous fossil Lagerstätte named after the nearby Burgess Pass. This site is high in the Canadian Rockies within Yoho National Park near the town of Field, British Columbia, Canada. The Burgess Shale was discovered in 1909 by famed paleontologist Charles Doolittle Walcott, who returned time and again to extensively study its fossils. Walcott described a large diversity of previously unknown arthropods, and most importantly many forms of previously unknown phyla as well as many forms that remain enigmatic today. The fossils were particularly important at the time to understand Cambrian paleobiology because of their often exquisite preservation that included soft body parts. Many such sites have since been discovered, most notably the Chengjiang Maotianshan Shales, which are collectively called sites with Burgess Shale-like preservation.

The Burgess Shale fossils are about 505 million years old, some 20 million years younger than those from Chengjiang. In fact, the Burgess Shale and Chengjiang have considerable overlap in faunal forms. Less well known is that Cambrian formations in the House Range of Utah yield many fossils like the Burgess Shale, though the soft tissue preservation is usually not as good.

The Burgess Shale extends in a large area Burgess Shale extends in outcrops erent faunal mixes. Scientists believe the deposits were formed when areas of muddy ocean floor slid into a lower place creating an anoxic (oxygen-starved) environment that was particularly favorable to fossilization because decay was inhibited.

Burgess Shale Fossils
Partial List of Burgess Shale Fauna Phylum Annelida Canadia Phylum Arthropoda Canadaspis Elrathina (trilobite) Leanchoilia Marella Naraoia Olenoides (trilobite) Perspicaris Ptychagnostus (trilobite) Sidneyia Yohoia Phylum Chordata Pikaia Phylum Ctenophora Ctenorhabdotus Fasciculus Xanioascus	Phylum Hyolitha Haplophrentis Phylum Mollusca Scenella Phylum Onychophora Aysheaia Hallucigenia Phylum Porifera Choia Phylum Priapulida Ottoia Phylum Incertae sedis Amiskwia Anomalocaris Dinomischus Nectocaris Odontogriphus Opabinia Orthrozanclus Wiwaxia
		Elrathina (= Ptychoparella) cordillerae Mass Mortality Class Trilobita Order Ptychopariida Family Alokistocaridae Walcott Quarry Shale Member	Marella splendens Phylum Arthropoda Order Marrellomorpha Stephen Formation Burgess Pass
Ptychagnostus praecurrens Class Trilobita Order Agnostida Family Ptychagnostidae Stephen Formation Burgess Pass	Scenella amii Phylum Mollusca (?) Family Scenellidae Stephen Formation Burgess Pass	Micromitra burgessensis Phylum Brachiopoda Family Paterinatidae Stephen Formation Burgess Pass