sometimes piles of rocks are formed by melting glaciers depositing rocks
pile_of_snow is pile. pile_of_rocks is not pile. pile_of_snow is not pile. sheet_pile is pile. shale is not sedimentary_rock. mineral_pile is pile. shale is sedimentary_rock. mound is pile_of_earth_or_sand. shale is clastic_sedimentary_rock. pile_of_rocks is pile.