The Deep Sea Drilling Project core collection offers unique opportunities for advances in pelagic biostratigraphy because (1) it represents a rather thorough sampling of the Cenozoic column in the oceans, (2) standard lithologic descriptions and preliminary stratigraphic interpretations of the cores are published routinely, and (3) samples and guides to investigations accomplished and under way are readily available.

A few DSDP sites with long sequences of well-preserved microfossils are being investigated by many workers, thus becoming reference sections through which pelagic stratigraphy is becoming consolidated. Quantitative methods are improving both the consistence of identifications of taxa and the meaningfulness of records of their occurrence. Investigations on the distortion of assemblages by dissolution and paleoenvironmental controls on the distribution of species and subspecies are providing information essential for improved biostratigraphic correlations. Sequences of events in each microfossil group are inevitably tied to those in other groups because all are investigated in the same set of cores. Paleomagnetic and isotopic investigations (mostly on non-DSDP cores) are linking these w th the absolute age scale to permit determination of rates of changes and recognition of diachronous events. The sheer volume of DSDP data is encouraging the development of new methods, such as the application of probabilistic statistics to correlation.

We can expect future emphasis on quantitative procedures as the qualitative ones become inadequate for the increasingly rigorous requirements of biostratigraphy. Concurrently, we will obtain a clearer picture of the phylogenetic changes which form the basis for natural taxonomic systems and for biostratigraphic interpretations.

End_of_Article - Last_Page 516------------