colluvium

Loose sediment that has accumulated at the base of a slope through the action of gravity — not carried by water or wind but simply fallen, slid, or crept downhill under its own weight. Colluvium is the material that gathers at the foot of a cliff, at the toe of a landslide, or along the lower edge of any steep terrain. It is unsorted, angular, and often unstable — a slope's debris pile, still in the process of arriving.