TIMELINE	Mesoproterozoic
Period	Subdivision	Timespan
Mesoproterozoic	Stenian	1,200,000,000 to 1,000,000,000 years ago
	Ectasian	1,400,000,000  to 1,200,000,000 years ago
	Calymmian	1,600,000,000 to 1,400,000,000 years ago