Proterozoic eon:

More on Proterozoic eon from Fact Monster:

• Table of Geological Periods - Table of Geological Periods It is generally assumed that planets are formed by the accretion of gas ...
• Precambrian - Precambrian Precambrian, name of a major division of geologic time (see Geologic Timescale, table), ...
• Encyclopedia: Geology and Oceanography - Encyclopeadia articles concerning Geology and Oceanography.

See more Encyclopedia articles on: Geology and Oceanography