18. Geologic Terms and Geographic Divisions
Geologic terms
For capitalization, compounding, and use of quotations in geologic terms, copy is to be followed. Geologic terms quoted verbatim from published material should be left as the original author used them; however, it should be made clear that the usage is that of the original author.
Formal geologic terms are capitalized: Proterozoic Eon, Cambrian Period. Structural terms such as arch, anticline, or uplift are capitalized when preceded by a name: Cincinnati Arch, Cedar Creek Anticline, Ozark Uplift. See Chapter 4 geographic terms for more information.
| Eon | Era | Period |
| Phanerozoic | Cenozoic | Quarternary. |
| Tertiary (Neogene, Paleogene). | ||
| Mesozoic | Cretaceous. | |
| Jurassic. | ||
| Triassic. | ||
| Paleozoic | Permian. | |
| Carboniferous (Pennsylvanian, Mississippian). | ||
| Devonian. | ||
| Silurian. | ||
| Ordovician. | ||
| Cambrian. | ||
| Proterozoic | Neoproterozoic | Ediacaran. |
| Cryogenian. | ||
| Tonian. | ||
| Mesoproterozoic | Stenian. | |
| Ectasian. | ||
| Calymmian. | ||
| Paleoproterozoic | Statherian. | |
| Orosirian. | ||
| Rhyacian. | ||
| Siderian. | ||
| Archean | Neoarchean | |
| Mesoarchean. | ||
| Paleoarchean. | ||
| Eoarchean. | ||
| Hadean. |
Source: Information courtesy of the U.S. Geological Survey; for graphic see http://pubs.usgs.gov/fs/2007/3015/fs2007-3015.pdf.
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