- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
Comments are given on a number of papers dealing with principles and procedure in stratigraphic classification which have appeared in British journals during 1963-65. It is emphasized that a clear distinction should be made between biostratigraphic units--bodies of rock strata characterized by certain paleontological features and bounded by the limits of known occurrence of such features--and chronostratigraphic units--bodies of rock strata characterized by representing the rocks formed during certain time-spans of earth history and bounded above and below by isochronous surfaces. Biostratigraphic zones and the chronostratigraphic terms chronozone and stage are discussed.