Related by context. Frequent words. (Click for all words.) 55 Chihuahuan Desert 54 trackways 53 Chaco Canyon 53 petroglyph 52 Fossilized 52 dinosaur fossils 51 lava tubes 49 limestone cave 49 dinosaur footprints 49 archaeologically 48 paleontological 48 petroglyphs 48 archaeological sites 48 rock outcrops 48 prehistoric 48 Sangre de Cristo Mountains 47 archeological sites 47 Paleocene 46 Ecological Reserve 46 feathered dinosaurs 46 cliff dwellings 46 fossilized 46 Late Cretaceous 46 Valles Marineris 46 Carlsbad Caverns 46 fossils 45 theropods 45 sagebrush habitat 45 marine reptiles 45 limestone caves 45 biodiversity hotspot 45 Burgess Shale 45 archeological 45 landform 45 petrified wood 45 fossilized bones 45 federally endangered 45 Book Cliffs 45 igneous rock 45 buttes 44 Paleontologists 44 Jurassic Period 44 landforms 44 pre Columbian 44 dinosaur fossil 44 theropod 44 archaeological 44 geological formations 44 Very Large Array 44 Teotihuacan 44 hadrosaur 44 middens 43 archaeological finds 43 bosque 43 Columbian mammoth 43 Inca empire 43 sedimentary rock 43 billed dinosaur 43 saber toothed cat 43 ancient pyramids 43 dinosaur bones 43 Galapagos islands 43 tyrannosaur 43 Spanish conquistadors 43 cenotes 43 Paracas 43 dinosaur 42 geologic 42 paleontology 42 Pre Columbian 42 Yucatán 42 fossilized remains 42 Mimbres 42 stegosaurus 42 Mesoamerican 42 palaeontology 42 fossil 42 coprolites 42 Namib Desert 42 glaciated 42 plesiosaur 42 Canyon de Chelly 42 ancient civilization 42 stromatolites 42 Tenochtitlan 41 biologically diverse 41 carnivorous dinosaurs 41 prehistoric creatures 41 trackway 41 woolly mammoths 41 calcareous 41 Kartchner Caverns 41 marine reptile 41 limestone formations 41 hydrothermal vent 41 karst 41 geologic formation 41 Cretaceous Period 41 Palaeolithic 41 salt flats 41 freshwater wetlands