1.8 - 1.74
1.74 - 1.68
1.68 - 1.62
1.62 - 1.56
1.56 - 1.5
300M
1.8 - 1.5
60M
8th Galactic year
7th 250 M Galactic year 1.75 - 1.5
Proterozoic Eon 2.5 - 540 M proterozoic eon
Precambrian Time 4.5 - 543 M precambrian
 
Mesoproterozoic 1.6 B - 900 M
 
- 1.6 B - 900 M Mesoproterozoic