The Neoproterozoic is the third of three subdivisions of the Proterozoic Eon (occurring from 1 billion years ago to 542 million years ago).
The Paleoproterozoic is the first of three subdivisions of the Proterozoic Eon (occurring from 2.5 billion to 1.6 billion years ago (Ga).
The Mesoproterozoic Era is a geologic era within the Proterozoic Eon, being the second of three periods, and falls in between the Paleoproterozoic and the Neoproterozoic eras.
The Proterozoic, meaning “earlier life,” is a geologic eon that follows the Archean.
The Archean (formerly Archaeozoic) is a geologic eon between the Hadean and Proterozoic eons.
The Hadean began with the formation of the Earth roughly 4.5 billion years ago (Ga) and ended about 3.8 Ga