The Precambrian Era makes up all time from the beginning of the Earth (about 4.5 billion years ago) until the start of the Cambrian, about 544 mya. This represents about 88% of all of Earth history.
The oldest known rocks on Earth have been dated to about 3.8 billion years. The first evidence for life is found in rocks about 3.4 billion years old, from the Fig Tree Group in Africa.
Classic Fossil-Bearing Sites
Fig Tree Group, Africa
Bulawayan Formation, Africa
Gunflint Iron Formation, Minnesota, Canada
Belcher Group, Hudson Bay
Bitter Springs, Australia
Ediacaran Sites, Australia
Several large impact structures are noted from the Precambrian. A 140 km structure dated to 1,970 mya is found in South Africa, a comparably-sized structure dated to 1,850 mya is found in Sudbury, Ontario, and a 150 km structure dated to 593 mya is found in South Australia.