Clay · Erosion · Pebble · Rain · River · Sediment

Rain falls. A River gathers the fall and runs it downhill. Erosion is the wearing that water and wind teach to mass. Sediment is what that wearing becomes when it settles. Clay is the wet fines. A Pebble is a stone already reduced, still itself.

Wash is the water–earth door. It is not another rock name and not another weather noun. Stone and Water take the split; Decay is the slow unmaking; Friction is contact along the way. The map keeps the six that turn a mountain into a bed.