"for the very first geological age," 1872, from Greek arkhaios "ancient," from arkhe "beginning" (see archon).
of or relating to the earliest recognised rocks formed during the Precambrian Eon
- Ancient; regarding the initial period in geological history.
- the initial period in geological duration, extending as much as the low Silurian. It provides an Azoic age, previous to the look of life, and an Eozoic age, like the very first forms of life.
(a.) Ancient; with respect to the initial period in geological record.
- (n.) The initial period in geological period, expanding around the low Silurian. It provides an Azoic age, previous to the appearance of life, and an Eozoic age, including the earliest types of life.
The low island of Anglesey, which is built tip of the fundamental Archaean rocks, is important as a link in the main line of communication with Ireland, because it is separated from the mainland by a channel narrow enough to be bridged, and lies not far out of the straight line joining London and Dublin.