the glacial destruction of the rocks that make up the bed of the glacier and the removal of the broken material (detached masses, boulders, pebbles, sand, clay, and so on) by a moving glacier. Exaration brings about the formation of glacial troughs, lake basins, sheepback rocks (roches moutonnées), glacial scarrings, and striations. In the course of destruction, the rocks are smoothed, ground, and polished.