ABSTRACT
The disciplines of palaeontology and stratigraphy are inextricably linked and it is not a surprise that fossils and their collections played and continue to play a major role in recognizing and correlating rock successions. Geological systems have traditionally been identified by their lithologies and fossil content. Collections in state and other recognized institutions are key references to the passage of geological time and organic evolution but are also fundamental for the correlation of rock successions. Stratigraphically-arranged displays, common in the nineteenth and early twentieth centuries have been commonly morphed into galleries show-casing the evolution of life. Nevertheless, chronostratigraphic units, such as systems, series and stages defined on their fossil content ultimately proved an unstable concept. Stages were recognized by the presence of groups of fossils initially in a type area and elsewhere on the occurrence of some or all of those in the type sections. Global Boundary Stratotype Sections and Points (GSSPs) are where rock meets time, at a point defined in a section and provide a more stable way to define and correlate rock successions.