Major Time-Divisions since the Pre-Cambrian

A summary of the terminology for the major elements of geologic time since the beginning of the Cambrian is given, with the present standing of those terms in modern usage. It is proposed to combine the Mesozoic and Cenozoic into a single era, the Neozoic, and to divide the Paleozoic into two eras, Eo-Paleozoic and Neo-Paleozoic. The name "Metazoic" is also suggested as a collective term for all time since the pre-Cambrian.