Related by context. Frequent words. (Click for all words.) 71 Cretaceous Period 71 Jurassic Period 70 Late Cretaceous 63 Mesozoic 63 Paleocene 61 Cambrian explosion 61 Carboniferous 61 Palaeolithic 61 interglacial period 60 Cretaceous 60 dinosaurs roamed 60 Burgess Shale 59 Precambrian 59 Pleistocene 59 glaciations 59 Quaternary 59 Ordovician 59 interglacial 58 Mesolithic 58 fossils 58 marine reptile 58 Ardipithecus ramidus 58 Pliocene 57 Younger Dryas 57 Eocene 57 Pleistocene era 57 supercontinent 57 H. erectus 56 prehistoric 56 Yuan Dynasty 56 trilobites 56 microfossils 56 faunal 56 Homo habilis 56 Ming Dynasty #-# 55 theropod 55 tetrapod 55 feathered dinosaurs 55 marine reptiles 55 marine sediments 55 hadrosaur 55 placental mammals 55 Australopithecus afarensis 55 Lower Cretaceous 55 Harappan 55 igneous rocks 55 Beringia 55 sauropod 55 stromatolites 55 dinosaur fossil 55 Khmer empire 55 tyrannosaur 54 Paleolithic 54 dinosaurs 54 relict 54 Snowball Earth 54 fossilized remains 54 limestone cave 54 Triassic 54 Anthropocene 54 Proterozoic 54 hydrothermal activity 54 coprolites 54 Radiocarbon dating 54 Tiktaalik 54 fossilized bones 54 basaltic 53 Columbian mammoth 53 megafauna 53 mammoths 53 pre Incan 53 degrees Fahrenheit warmer 53 hominid 53 Oligocene 53 Diplodocus 53 Jurassic 53 glaciation 52 dinosaur fossils 52 hominins 52 Paleozoic 52 Australopithecus 52 foraminifera 52 Archaeopteryx 52 Amenhotep III 52 Tang Dynasty #-# 52 Qing dynasties 52 volcanism 52 sedimentary rock 52 anatomically modern 52 continental crust 52 billed dinosaur 52 temperate forests 52 Neandertal 52 plesiosaur 52 flint tools 51 anthropoids 51 dinosaur footprints 51 hominin 51 lavas 51 lava tubes 51 anthropoid