Related by context. Frequent words. (Click for all words.) 68 Late Cretaceous 63 Mesozoic 62 Carboniferous 62 Paleocene 60 Burgess Shale 60 Early Cretaceous 59 Archaean 59 Cretaceous 59 trilobites 59 marine reptiles 58 morphologies 58 Ordovician 57 Triassic 57 Cenozoic 57 Lower Cretaceous 57 Jurassic 57 biogeochemical 56 Jurassic Period 56 Eocene 56 Quaternary 56 Cretaceous Period 56 Pliocene 56 igneous rocks 55 ammonites 55 Paleozoic 55 marine iguanas 55 landforms 55 Precambrian 55 Diplodocus 55 depositional 55 lava tubes 54 Upper Cretaceous 54 fossils 54 geologic 54 marine invertebrates 54 stratiform 54 planktonic 54 Proterozoic 53 Namib Desert 53 faunal 53 arthropod 53 carnivorous dinosaur 53 Dry Valleys 53 preserved fossils 53 Polar Regions 53 theropod 53 gossans 52 massive sulphide deposits 52 metamorphic rocks 52 siliceous 52 hydrothermal vent 52 prehistoric 52 DINOSAURS 52 marine sediments 52 schists 52 stromatolites 52 banded iron 52 clasts 52 Oligocene 52 Silurian 52 placental mammals 52 tuffs 52 Brachiosaurus 52 sauropods 52 Valles Marineris 52 greenstone belts 51 gravity anomalies 51 Cambrian explosion 51 Palaeolithic 51 dinosaurs 51 #km# [002] 51 volcanogenic massive sulphide 51 mudstones 51 interbedded 51 magmas 51 basalts 51 basaltic 51 undersea volcanoes 51 Ardipithecus ramidus 51 vuggy silica 51 theropods 51 surficial 51 Geochemistry 51 Skarn 51 terrestrial ecosystems 51 Miocene 51 biomes 51 Frankfield East 51 carnivorous dinosaurs 51 geologic formations 51 Dinosaurs Alive 51 theropod dinosaurs 51 glaciations 51 Stegosaurus 51 Younger Dryas 51 rock outcrops 50 interglacial 50 Near Surface 50 hadrosaur 50 bathymetry 50 saber toothed tigers