Related by context. Frequent words. (Click for all words.) 56 earthen mounds 54 midden 53 burial mounds 52 Cahokia Mounds 52 limestone 52 palisade 51 sandstone cliffs 51 limestone cave 50 excavated 50 cliff dwellings 49 megaliths 49 Cerro Rico 49 limestone caves 49 granite cliffs 49 archaeological finds 49 sandstone 49 Columbian mammoth 49 grassy plains 49 Chaco Canyon 49 mounds 48 prehistoric 48 trackway 48 bluffs overlooking 48 henge 48 fieldstone 47 petroglyph 47 granite boulders 47 crushed limestone 47 stone arches 47 basalt 47 stromatolites 47 grassy slopes 47 cement slab 47 Great Pyramid 47 earthwork 47 granite stones 47 tombs 47 obelisks 47 escarpments 47 lava tubes 47 Mound Cemetery 47 Egyptian pharaohs 47 Burgess Shale 47 rock outcrops 46 horned dinosaur 46 earthen walls 46 middens 46 coulee 46 Palaeolithic 46 earthworks 46 Inca Empire 46 earthen wall 46 grassy hillside 45 graben 45 stupa 45 sandstone formations 45 Khufu 45 lakebed 45 stalactite 45 marble slabs 45 sedimentary rock 45 rock outcrop 45 stone slab 45 earthen 45 placer deposits 45 Herodium 45 moraines 45 elaborately carved 45 caliche 45 chert 45 pictographs 45 granite boulder 45 granite stone 45 bottomland 44 hardened lava 44 ancient 44 stonework 44 archaeological 44 coulees 44 petroglyphs 44 volcanic crater 44 hadrosaur 44 alluvium 44 archeological 44 cypress swamps 44 stone slabs 44 granite quarry 44 Egyptian pyramids 44 Harappa 44 stele 44 Mesolithic 44 drainage basins 44 fossils 44 primeval forest 44 oxbow 44 moss covered 44 fossil specimens 44 burial grounds 44 quarried 44 pre Incan 44 ancient pyramids