Editing Pre-Nectarian (section)

==Relationship to Earth's geologic time scale==
Since little or no [[geology|geological]] evidence on [[Earth]] exists from the time spanned by the pre-Nectarian period of the Moon, the pre-Nectarian has been used as a guide by at least one notable scientific work<ref>{{cite book | title = A Geologic time scale 1989 | publisher = Cambridge University Press | year = 1990 |author1=W. Harland |author2=R. Armstrong |author3=A. Cox |author4=L. Craig |author5=A. Smith |author6=D. Smith }}</ref> to subdivide the unofficial terrestrial [[Hadean]] [[eon (geology)|eon]]. In particular, the [[Hadean|Hadean eon]] is subdivided into the [[Cryptic era]], [[Basin Groups]] 1-9, [[Nectarian]] and [[Lower Imbrian]], though the first two of these lunar divisions are informal and collectively make up the pre-Nectarian.