Geological units
Požáry formation (Silurian / Pridoli )
Pragian (Devonian / Lower Devonian )
Priabonian (Paleogene / Eocene )
Pridoli (Silurian )
Rhaetian (Triassic / Upper Triassic )
Rhuddanian (Silurian / Llandovery )
Rhyacian (Proterozoic / Paleoproterozoic )
Roadian (Permian / Guadalupian )
Rupelian (Paleogene / Oligocene )
Sakmarian (Permian / Cisuralian )
Sandbian (Ordovician / Upper Ordovician )
Santonian (Cretaceous / Upper Cretaceous )
Scollard Formation (Upper Member) (Paleogene / Paleocene / Danian )
Selandian (Paleogene / Paleocene )
Serpukhovian (Carboniferous / Mississippian )
Serravallian (Neogene / Miocene )
Sheinwoodian (Silurian / Wenlock )
Siderian (Proterozoic / Paleoproterozoic )