The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.
Cretaceous
The Cretaceous (pronunciation: /krᵻˈteɪʃəs/, krə-TAY-shəs) is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago (Mya) to the beginning of the Paleogene Period 66 Mya.
Cryogenian
The Cryogenian (pronunciation: /kraɪoʊˈdʒɛniən/, from Greek cryos "cold" and genesis "birth") is a geologic period that lasted from 720 to 635 million years ago.
Jurassic
The Jurassic (pronunciation: /dʒuːˈræsɪk/; from Jura Mountains) is a geologic period and system that spans 56.
Ordovician
The Ordovician (pronunciation: /ɔːrdəˈvɪʃən/) is a geologic period and system, the second of six of the Paleozoic Era, that spans 41.
Paleogene
The Paleogene (pronunciation: /ˈpæliːədʒiːn/ or /ˈpeɪliːədʒiːn/; also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago (Mya) to the beginning of the Neogene Period 23.
Permian
The Permian is a geologic period and system which spans 46.
Quaternary
The Quaternary Period (pronunciation: /kwəˈtɜːrnəri/) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS).
Silurian
The Silurian is a geologic period and system spanning 24.
Ice age
An ice age is a period of long-term reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
Tertiary
Tertiary is the former term for the geologic period from 66 million to 2.