Related by context. Frequent words. (Click for all words.) 66 trilobites 66 foraminifera 60 Late Cretaceous 59 calcareous 59 Mesozoic 59 marine invertebrates 59 diatoms 58 theropod 58 Paleocene 58 planktonic 57 Eocene 57 Ordovician 57 morphologically 57 theropods 57 Paleozoic 56 temperate forests 56 Carboniferous 56 baleen whales 56 taxa 56 hydrothermal vent 56 stromatolites 56 fossils 56 lavas 55 diatom 55 calcite 55 zircons 55 feathered dinosaurs 55 marine reptiles 55 arthropods 55 microfossils 55 shallower depths 55 tyrannosaur 55 tetrapods 55 marine sediments 55 Precambrian 54 mammals 54 lake sediments 54 Sperm whales 54 species 54 herbivorous 54 invertebrates 54 narwhals 54 Cretaceous 54 crustaceans 54 basalts 54 mudstone 54 fossil 54 Pliocene 53 middens 53 tetrapod 53 narwhal 53 Triassic 53 molluscs 53 oystercatchers 53 geologically 53 abundances 53 bowhead 53 terrestrial ecosystems 53 arthropod 53 petrels 53 benthic 53 Tiktaalik 53 biota 53 Burgess Shale 53 vertebrates 53 mollusks 53 megafauna 53 zooplankton 53 sediment cores 52 Archaeopteryx 52 olivine 52 coprolites 52 plesiosaur 52 sedimentary rocks 52 vertebrate species 52 Cretaceous Period 52 symbionts 52 carnivorous dinosaurs 52 isotopic composition 52 gobies 51 Homo habilis 51 Ardipithecus 51 Lower Cretaceous 51 sea anemones 51 cephalopods 51 anomalously 51 vertebrate 51 tyrannosaurs 51 tuffs 51 siliceous 51 hydrothermal breccias 51 hadrosaur 51 crocodilians 51 Humboldt squid 51 copepods 51 ptarmigan 51 spherules 51 Pleistocene 51 rock outcrops 51 prokaryotes 51 hominins