Related by context. Frequent words. (Click for all words.) 70 Cretaceous Period 63 Late Cretaceous 63 interglacial period 62 Pleistocene 62 interglacial 61 dinosaurs roamed 59 Younger Dryas 57 Pliocene 56 Cretaceous 55 Fertile Crescent 55 Little Ice Age 54 Eocene 54 glaciation 53 Carboniferous 53 Quaternary 53 Mesozoic 53 mammoths 52 Ice Age 52 megafauna 52 marine sediments 51 Medieval Warm Period 51 Holocene 51 woolly mammoths 51 Triassic 51 anatomically modern 51 prehistoric 50 Mammoths 50 Homo sapiens 50 prehistory 50 Paleocene 49 woolly mammoth 49 trilobites 49 Neanderthals 49 Jurassic 49 Paleolithic 48 Precambrian 48 dinosaurs 48 continental crust 48 Neandertals 47 musk oxen 47 Paleozoic 47 Bering Strait 47 Oligocene 47 fossilized remains 47 Ordovician 47 Fossils 47 landmasses 46 hunter gatherers 46 fossils 46 Miocene 46 preindustrial 46 volcanism 46 marine reptiles 45 mass extinctions 45 interbred 45 millenniums 45 retreating glaciers 45 ocean ridges 45 lavas 45 Homo erectus 45 Gondwana 44 mass extinction 44 Ellesmere Island 44 temperate zones 44 vertebrate species 44 continental drift 44 dinosaur footprints 44 extinct 44 epochs 44 millennia 44 Ross Ice Shelf 44 icecap 44 fossilized 44 glacial ice 44 Volcanic eruptions 44 Lower Cretaceous 44 radiocarbon dating 43 hominins 43 Weddell Sea 43 overhunting 43 fossilized bones 43 Australopithecus afarensis 43 sedimentary rock 43 Bronze Age 43 plate tectonics 43 tetrapods 43 glaciated 43 Neandertal 43 equatorial Pacific Ocean 43 glacial 43 plesiosaur 43 microfossils 42 lake sediments 42 Han Dynasty 42 sediments 42 Mormon pioneers 42 zircons 42 hibernated 42 ancient Mayans 42 Australopithecus 42 hominids