| C Carboniferous |
| CD Carboniferous and Devonian |
| Cm Cambrian |
| D Devonian |
| DS Devonian and Silurian |
| Du Upper and Middle Devonian |
| Internal Water Body |
| J Jurassic |
| JC Jurassic through Carboniferous |
| JTr Jurassic and Triassic |
| JI Lower Triassic |
| K Cretaceous |
| KC Cretaceous through Carboniferous |
| KJ Cretaceous and Jurassic |
| Kimb Kimberlite |
|
| Kl Lower Cretaceous |
| Mi Mesozoic extrusive and intrusive rock |
| MiPi Mesozoic-Paleozoic extrusive and intrusive rock |
| Mz Mesozoic |
| MzPz Mesozoic and Paleozoic |
| O Ordovician |
| OCm Ordovician-Cambrian |
| P Permian |
| PC Permian-Carboniferous |
| Pi Paleozoic extrusive and intrusive rock |
| Pz Paleozoic |
| PzpC Paleozoic-Precambrian |
| Q Quaternary (undivided) |
| QT Cenozoic |
| Qe Holocene |
| Qp Pleistocene |
| Qv Quaternary extrusive and intrusive rocks |
| S Silurian |
| SO Silurian-Ordovician |
| S_d Salt Domes |
| T Tertiary |
| TK Tertiary and Cretaceous |
| Ti Tertiary extrusive and intrusive rock |
| Tr Triassic |
| TrP Triassic and Permian |
| Trl Lower Triassic |
| Area outside the African Continent |
| pCm Precambrian (undivided) |
