period, time, rocks, age, cretaceous, boundary, strata, times, sediments, lower, deposits, limestones, beds, formation, fossils, limestone, rifting, formations, flora, forms, plants, stratigraphy, sandstones, shales, fauna, ammonites, erosion, sequence, event, extinctions, transition, basement, arc, rock, sandstone, geology, mammals, clays, basins, crust, surface, assemblages, sedimentation, park, scale, unconformity, coal, evolution, triassic, dinosaurs, reptiles, faunas, dikes, series, floras, paleogeography, era, eocene, biogeography, spores, climates, magmatism, genus, granite, cracow, flint, upper, plutons, extinction, miocene, basin, doming, deposit, succession, reefs, onwards, unconformities, provinces, bed, ages, interval, sequences, paleocommunities, seas, forest, orogeny, slates, coals, paleogene, fishes, sea, corals, reservoirs, neocomian, outcrops

late, early, middle, latest, marine, mid, pre, uppermost, post, earliest, later, lowermost, older, permian, earlier, thick, probable, folded, continental, chalky, lowest, younger, ordovician, basal, permo, carboniferous, rhaetic, clastic, primitive, eroded, recorded, opaque, youngest, devonian, salt, lying, nonmarine, onshore, geologic, fossiliferous, terminal, boreal, bearing