Slickenside - a smoothly polished surface caused by frictional movement between rocks along the two sides of a fault.

In pedology, the study of soils in their natural environments, a slickenside is a surface of the cracks produced in soils containing a high proportion of swelling clays.

The residual strength occurs for some soils where the shape of the particles that make up the soil become aligned during shearing (forming a slickenside), resulting in reduced resistance to continued shearing (further strain softening).

Some of the most well known canyons include Slickenside Canyon, Talc Canyon, Owlshead Canyon, Contact Canyon, Granite Canyon, Through Canyon, Smoke Tree Canyon, Passage Canyon, Sand Canyon, and Sagenite Canyon.