Proterozoic

(redirected from Proterozoic eon)
Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to Proterozoic eon: Hadean eon, Archean eon, Paleozoic era, Phanerozoic eon

Proterozoic

that period of geological time lasting from some 2600 million to 589 million years ago; the part of Cryptozoic time excluding the Archaean Period. Fossils dating from this period are mainly CYANOBACTERIA.