<P> The primary defined divisions of time are eons , in sequence the Hadean , the Archean , the Proterozoic and the Phanerozoic . The first three of these can be referred to collectively as the Precambrian supereon . Eons are divided into eras , which are in turn divided into periods , epochs and ages . </P>
<P> The primary defined divisions of time are eons , in sequence the Hadean , the Archean , the Proterozoic and the Phanerozoic . The first three of these can be referred to collectively as the Precambrian supereon . Eons are divided into eras , which are in turn divided into periods , epochs and ages . </P>
what unit of geologic time is the greatest span of time
what unit of geologic time is the greatest span of time
eons
eons