The underneath part of the glacier may have captured rocks in the ice, and as the glacier moves, it grinds the rocks beneath it. Glaciers move all sizes of rocks, and grind some of the stones to a very fine dust called gl acial flour. Wave Action Tides show erosion in action. The constant movement of the waves shows us how sand grains are tumbled, and the returning water traces miniature drainage channels in the sand. The rocks and stones on the beach are rounded from thousands of years of being rolled against each other or washed by sand-carrying breakers.
Waves also erode cliffs along the beaches.
They undercut the cliffs, and eventually the cliffs fall. The ocean along the coast of California is slowly pushing back the cliffs. Wind Wind picks up dust and sand. Sand storms can act like sand blasters if the wind is moving fast enough. In the desert the wind moves the sand into dunes, piling it up and covering the surfaces with ripples.