Happy anniversary - to a fossil find

It's the 100th anniversary of the discovery of the Burgess Shale - a formation so filled with fossils that its study led to our understanding of the evolutionary flowering known as the "Cambrian Explosion." Our understanding has evolved over the years, and is still evolving. Some earlier conclusions (including some cataloged in Gould's book Wonderful Life) have changed, but not the importance of the find itself.