The Precambrian is the longest period of time before the Phanerozoic Eon, and stretches from the formation of the Earth at roughly 4.6 billion years ago to the beginning of the Cambrian about 541 million years ago. The Precambrian is subdivided into several eons (see timescale) and represents roughly 88% of geologic time.
Fossils of Precambrian age in Idaho occur in the Proterozoic age rocks of the Belt Supergroup of central Idaho and in the latest Protoerozoic Brigham Quartzite of southeastern Idaho. These remains consist of layered remains of algae known as stromatolites, as well as various invertebrate trace fossils from worm-like animals.
Fossils of Precambrian age in Idaho occur in the Proterozoic age rocks of the Belt Supergroup of central Idaho and in the latest Protoerozoic Brigham Quartzite of southeastern Idaho. These remains consist of layered remains of algae known as stromatolites, as well as various invertebrate trace fossils from worm-like animals.