classification of/characterized by have as classification/classify class of/classification have as classification/classify object of/classification of object of/classification of reference/classify be classified by/classify boundary class boundary classification feature boundary local rock feature material class material classification rock component rock feature rock feature rock feature part rock fluid feature rock fluid feature class rock fluid feature classification rock in outcrop rock material rock sample seismic feature seismic feature class seismic feature classification subsurface rock segment geologic feature material rock feature part geologic object