This volume will draw the attention of everyone interested in the fascinating diversity of
ancient ecosystems such as reefs and shell accumulations in the Palaeozoic, whose
difficulty of study rests primarily on its multidisciplinary position crossing numerous
geological disciplines. Their facies characterization is, like many other biosedimentary
structures, a process that requires the acquisition and integration of a wide and multiscale
diversity of observations, which include field (global geometries), sample (fabrics),
and thin-section (textures) scales.
One of the messages of this collection of papers is the wide diversity of sedimentary
geometries and facies displayed by Palaeozoic reefs, shell accumulations, and transitional
composite deposits. We have touched on some of the major issues at this stage of development
in the field: the major climatic, environmental and evolutionary factors that
controlled the Palaeozoic development of shell accumulations and reefs.