Less than one third of Phanerozoic chronostratigraphic units has been formally defined in the last thirty years.Two thirds are still floating. A common relative chronologic language is crucial to mode communication among the different disciplines stemming from the old geoscience root and with the neighboring physical,chemical, natural and environmental sciences. To strengthen the perspectives of geosciences in the near future and test the capacity of geologists to succeed in co-operative scientific goals, every effort should be made to complete definition of the chronostratigraphic scale within the next decade.