"The Burgess Shale fossils merit special interest for several reasons:
Their age - from the Cambrian period, 505 million years ago, shortly after an astonishing burst of biodiversity occurred in the ancient oceans.
Their exquisite preservation - amazingly fine details of the structure of the animals are seen in the fossils, which tell paleontologists much more about what the ancient animals looked like, and how they lived.
The fossils reveal important clues to the nature of
evolution - all of the major types of animals (phyla)
known today are represented in the Burgess Shale, plus
others that cannot be placed in our modern