unconformityunconformity icebergunconsolidatedunconsolidated materialunconsolidated soiluncontrolled mosaicuncorrelated random variablesuncorrelated samplesuncountable setundaformundathemundation theory or undation or undationundecileunder designunderclay limestone or limestone or limestoneundercliffunderconsolidationundercooling or supercooling or supercoolingundercount in decennial censusundercutundercuttingunderdrainunderestimationunderground iceunderground mineunderground mining or minning or minningunderground minning or minning or minningunderground powerhouseunderground surveyingunderground water basinunderloaded streamunderlyingundermassundermeltingunderminingunderpinningunderplatingundersanded concreteundersaturated permafrostundershootundersluiceunderthrust faultundertow markundisturbedundisturbed sampleundrained shear testundular jumpundulating foldunenlagia comahuensisunequal leg angle section
