Related by context. Frequent words. (Click for all words.) 69 lava tube 64 landforms 63 rock outcrops 62 volcanic rock 61 volcanic crater 61 lava flows 60 rocky outcrops 60 rock formations 60 hydrothermal vents 60 rock outcrop 59 basalt 58 stalactites 58 stalagmites 58 magma chamber 58 caves 57 volcanoes 57 basalts 57 landform 57 sedimentary rock 57 seamount 57 middens 57 basaltic 57 lavas 57 outcroppings 57 caldera 56 lava 56 lava rocks 56 outcrops 56 geological formations 55 volcanism 55 extinct volcano 55 rocky outcroppings 55 volcanic islands 55 rock outcroppings 55 outcrop 55 calcite 55 calcareous 55 volcanic 54 hot springs 54 petroglyph 54 salt crystals 54 seamounts 54 ridges 54 oceanic crust 54 caverns 54 trilobites 53 continental crust 53 Meridiani 53 sandstone 53 gullies 53 methane hydrate 53 cave 53 cairns 53 scarps 53 sandstone cliffs 53 olivine 53 geologic 53 hydrothermal 53 landmasses 53 volcanic gases 53 fossils 53 cavern 53 Martian landscape 52 granite boulders 52 marine sediments 52 volcanically active 52 cliff dwellings 52 Paleocene 52 Kilauea Volcano 52 stalagmite 52 crater rim 52 kelp beds 52 Saturn moons 52 sandbars 52 dunes 52 intertidal 52 Sandia Mountains 52 magmatic 52 meteoroids 52 massif 52 geologic formations 52 sediments 52 volcanic rocks 51 moraines 51 geologically 51 vortexes 51 geologic formation 51 kelp forests 51 waterfalls 51 rock outcropping 51 craters 51 alluvium 51 adobe walls 51 graben 51 sheer cliffs 51 boulder strewn 51 fluvial 51 moon Europa 51 Kuiper belt 51 volcanic activity 51 polar caps