Related by context. Frequent words. (Click for all words.) 58 loess 57 limestone formations 56 silts 55 streambeds 53 sandstone formations 53 decaying vegetation 53 igneous rock 52 deciduous forests 52 rotting vegetation 52 mudstone 52 calcium sulfate 51 manganese oxide 51 coarse sand 51 clasts 51 creek bottoms 51 silt 51 silica 51 acidic soils 51 pyroclastic 50 glacial till 50 iron oxides 50 pebbly 50 sulfide minerals 50 pyrite pyrrhotite 50 basaltic 50 lichen 50 calcite 49 sparse vegetation 49 naturally occurring mineral 49 chalky white 49 hygroscopic 49 calcareous 49 montane 49 escarpments 49 landform 48 tussocks 48 powdery sand 48 silty 48 kaolinite 48 granite cliffs 48 talus 48 hardened lava 48 sediment 48 silicate 48 embayment 48 steep ravines 48 rock outcroppings 48 striations 48 tannic acid 48 deep gorges 48 evaporation ponds 48 coniferous forests 48 roadbeds 47 pumice 47 tailing ponds 47 hardpan 47 ridgetops 47 bamboo groves 47 chlorite 47 steam vents 47 oxbows 47 salt crystals 47 dense canopy 47 quartz sand 47 corundum 47 siliceous 47 landforms 47 limestone caves 47 mussel shells 47 decomposed granite 47 greenish brown 47 andesitic 47 coquina 47 fumaroles 47 lava flows 47 lava tubes 47 airborne particulates 47 sludges 47 bottomland 46 clastic 46 erosional 46 boulder strewn 46 marl 46 sandy loam 46 temperature inversions 46 granulate 46 rock outcrops 46 limestone 46 extinct volcanoes 46 geotextile 46 ashfall 46 hillocks 46 ridges 46 boulders 46 Topsoil 46 deep ravines 46 marine sediments 46 arsenate 46 mudstones 46 oxidise 46 Sulfur dioxide