VI.    NAME ALTERNATIVES


                   

Geology began in the 1800s with an initial subset of knowledge, based mostly on stratification and fossils, but not on events or carbon-dating. Prehistory was named simply and empirically into four great time-frames:

1. Primary (=primordial);
2. Secondary (=Jurassic and Cretaceous periods);
3. Tertiary (=first two periods of the Cenozoic era); and,
4. Quaternary (=rest of the Cenozoic, the modern mammalian time).

The term “pre-Cambrian” was also used for what are now three named aeons predating an explosion of the fossil record in the Cambrian period, (thought then to be the beginning of life). Though obsolescent in post-1977 nomenclature, “pre-Cambrian” is still used for convenience, and “Quaternary” has been retained out of a kind of sentiment, though “Primary”, “Secondary”, “Tertiary” are now passé.

Of the five “ice ages” in earth’s history, only the current one has been short enough to be called an “age”, according to present-day terminology. The rest are of period length, or even as long as an era! Therefore, in this summary, they are simply called “glacials”.