Introduction

Soft-tissue preservation has three important implications. First, the study of soft-part morphology alongside the morphology of the shell or skeleton allows better comparison with living forms and provides additional phylogenetic information. Second, it enables the preservation of animals and plants which are entirely soft bodied and which would normally stand no chance of fossilization. For example, it has been estimated that 85% of the animals in the Burgess Shale (Chapter 2) are entirely soft bodied and are therefore absent from Cambrian biotas preserved under normal taphonomic conditions. The third implication follows – such Conservation Lager - stätten therefore preserve for the palaeontologist a complete (or much more nearly complete) ecosystem. Comparison of such horizons in a chronological framework gives us an insight into the evolution of ecosystems over geological time.