↑Paleontólogos frequentemente preferem estágios faunais a períodos geológicos. A nomenclatura dos estágios é um tanto complexa. Ver «The Paleobiology Database». Consultado em 19 de março de 2006 para uma excelente lista em ordem cronológica dos estágios faunais.
↑Datas são muito imprecisas, com diferenças de alguns poucos pontos percentuais entre várias fontes, que são comuns. This is largely due to uncertainities in radiometric dating and the problem that deposits suitable for radiometric dating eldom occur exactly at the places in the geologic column where they would be most useful. The dates and errors quoted above are according to the International Commission on Stratigraphy 2004 time scale. Dates labeled with a * indicate boundaries where a Global Boundary Stratotype Section and Point has been internationally agreed upon: see List of Gclobal Boundary Stratotype Sections and Points for a complete list.
↑ abHistoricamente, o Cenozoico divide-se nas sub-eras Quaternário e Terciário, tanto quanto nos períodos Neoceno e Paleoceno. No entanto, a International Commission on Stratigraphy recentemente decidiu parar de utilizar os termos Quaternário e Terciário como parte da nomenclatura formal.
↑The start time for the Holoceno epoch is here given as 11,430 years ago ± 130 years (that is, between 9610 B.C. and 9350 B.C.). For further discussion of the dating of this epoch, see Holocene.
↑Though commonly used, the Hadeano is not a formal eon and no lower bound for the Archean has been agreed upon. The Hadean has also sometimes been called the Priscoan or the Azoic. Sometimes, the Hadean can be found to be subdivided according to the lunar geologic time scale. These eras include the Cryptic and Basin Groups (which are subdivisions of the pre-Nectarian era), Nectarian, and Lower Imbrian eras.
↑ abcdSince little or no geological evidence on Earth exists from the time spanned by the Hadean Eon, Eras of the Moon have been used by at least one notable scientific work as unofficial subdivisions of the terrestrial Hadeanoeon. (W. Harland, R. Armstrong, A. Cox, L. Craig, A. Smith, D. Smith (1990). A Geologic time scale 1989. Cambridge University Press.)
