A reinvestigation of the fossils in the 1980s by Wittington, Morris and Biggs revealed that the fauna represented was much more diverse and unusual than Walcott had recognized. Indeed, many of the animals present had bizarre anatomical features and only the sketchiest resemblence to other known animals. Examples include Opabinia with five eyes and a vacuum cleaner like snout; Aysheaia which bears an extrordinary resemblance to a minor modern Phylum -- the Onychophora?; Nectocaris which is apparently either a crustacean? with fins or a vertebrate? with a shell; and Hallucigenia which pretty much defied rational description (though it was later proven an onychophoran).
The diversity and exotic nature of the Burgess faunas has caused a great deal of controversy in paleontology with regard to the reasons for and nature of what has come to be called the [Cambrian Explosion]?.
Further investigations showed that the Burgess Shale extends for many miles in isolated outcrops and the various faunas are preserved in different places. The deposits appear to represent small areas of muddy ocean bottom that -- from time to time -- slid down the face of a limestone cliff carrying their fauna and anything unfortunate enought to be swimming by into oxygen poor waters in the depths. Knowing what to look for, similar deposits have been identified elsewhere with similar faunas. The most important similar deposits are even older turbide flow deposits created in much the same way as the Burgess shales in Yunnan Province, China. These [Maotianshan shales]? contain faunas quite similar to the Burgess.