Two types are recognized: Rock Slides and Debris Slides. Slides, like slumps and falls, involve the rapid displacement of masses of rock or sediment. In slides the movement is translational that is, uniform movement in one direction with no rotation.  Translational slides are also called block glides because they involve the movement of relatively coherent blocks of material along well-defined. inclined surfaces such as faults, foliation planes (in metamorphic rocks) or layering (in sedimentary rocks or alternating sequences of rock types). A rockslide is the sudden downslope movement of detached masses of bedrock (or of debris, in the case of a debris slide). Rockslides and debris slides are common in high mountains where steep slopes abound.