Related by context. Frequent words. (Click for all words.) 68 Cretaceous Period 63 Late Cretaceous 62 interglacial 62 interglacial period 58 Carboniferous 57 Pleistocene 57 Eocene 56 Ordovician 56 Pliocene 56 Paleocene 56 dinosaurs roamed 56 Quaternary 55 supercontinent 54 Cretaceous 53 radiocarbon 53 trilobites 52 Holocene 52 Oligocene 52 Younger Dryas 51 fossilized remains 51 Mesozoic 51 microfossils 51 hadrosaur 51 atmospheric methane 51 Triassic 51 fossils 50 glaciation 50 prehistoric 50 mass extinctions 50 Australopithecus 50 Neandertal 50 marine reptiles 49 Precambrian 49 Fertile Crescent 49 fossil 49 Paleolithic 49 coprolites 49 sediment cores 49 Ardipithecus 49 marine sediments 48 diatoms 48 anatomically modern 48 Medieval Warm Period 48 Neandertals 48 tetrapods 48 Devonian 48 lake sediments 48 Paleozoic 48 diatom 48 radiocarbon dating 48 Ice Age 48 multicellular 47 Homo sapiens 47 woolly mammoths 47 carnivorous dinosaurs 47 lavas 47 Archaeopteryx 47 sedimentary rock 47 megafauna 47 single celled organisms 47 stalagmite 47 Lower Cretaceous 47 Tiktaalik 46 common ancestor 46 Jurassic 46 Homo habilis 46 continental crust 46 prehistory 46 Australopithecus afarensis 46 Silurian 46 multicellular organisms 46 geologic 45 Miocene 45 plesiosaur 45 millennia 45 Fossils 45 solar nebula 45 palaeontologists 45 middens 45 prokaryotes 45 tyrannosaur 45 dinosaurs 45 retreating glaciers 45 millenniums 45 sediments 45 Little Ice Age 45 Proterozoic 45 mammals 45 theropods 44 oxygen isotopes 44 archaea 44 Archaea 44 hominid 44 vertebrate species 44 preindustrial 44 landforms 44 Neanderthals 44 mammoths 44 volcanism 44 #BC [003] 44 zircons