Assumptions that biostratigraphy is "all done". If all the above aims are met, the value of biostratigraphy will be appreciated by the wider geoscience community and recruitment and resourcing of biostratigraphers and geochronologists will move in a positive direction. But more importantly, industrial biostratigraphers have refocused their efforts on assisting production and development rather than exploration, as oil companies concentrate on exploiting more of their existing reserves rather than discovering entirely new fields. Chapters in the history of life Their maps also allowed them to organize the history of life into a series of chapters, from the Cambrian with its bizarre invertebrates to the dinosaurs of the Jurassic to the mammals of more recent times.
It has received different meanings and is now generally used as a subdivision of a biozone or subbiozone. If rocks of unknown age have traces of E. Berggren, R. The relationship of biostratigraphic units to other kinds of stratigraphic units is discussed in Chapter