Related by context. Frequent words. (Click for all words.) 53 streambeds 53 geologic formations 52 sandstone formations 52 streambanks 51 coniferous forests 51 marine sediments 51 granite cliffs 51 geological formations 50 undersea volcanoes 50 steam vents 50 temperate forests 50 basalts 50 fumaroles 50 geologic formation 49 lava tubes 48 escarpments 48 beaver pond 48 groundwater aquifers 48 basalt 48 volcanic vents 48 mud volcanoes 48 rock formations 48 streambed 48 lakebed 48 clathrates 48 mineshafts 48 magma chamber 47 basin 47 sedimentary rock 47 magmas 47 Aquifers 47 barrens 47 drainage basins 47 evaporation ponds 47 extinct volcanoes 47 coulees 47 rocky ledges 47 shallow aquifer 46 uranium tailings 46 loess 46 erosional 46 beaver ponds 46 Olympus Mons 46 lava tube 46 Hebgen Lake 46 salt domes 46 igneous rocks 46 decaying vegetation 46 methane hydrate 46 hydrothermal vent 46 volcanic rock 46 evergreen forests 46 sediments 46 embayment 46 limestone formations 45 deciduous forests 45 rugged cliffs 45 aquifers 45 Pueblo Reservoir 45 rock outcrops 45 caverns 45 alpine lakes 45 absorbs carbon dioxide 45 polar craters 45 creekbed 45 hot springs 45 naturally occurring mineral 45 slag pile 45 seabeds 45 coulee 45 Sediments 45 Radioactive waste 45 conifer forests 45 Contaminated soil 45 sediment 45 Naches River 45 granitic rocks 45 aspen groves 45 Arctic permafrost 45 basins 45 melting glacier 45 rocks 45 whitewater rapids 45 tropopause 45 lava 45 polluted groundwater 45 gyres 44 permafrost 44 Omo River 44 caldera 44 headwater streams 44 contaminating groundwater 44 intertidal zone 44 Hanford Site 44 icecap 44 precipices 44 temperate rainforest 44 seawater 44 spatial scales 44 glacial lakes 44 steep ravines