Also of importance to understanding hillslope geomorphology is the determination of the time since the bedrock hollows were last free of colluvium. This may provide information about the recurrence interval of landsliding at a particular location on a hillslope, which is essential to constructing sediment budgets (see Dietrich et al. 1982, for further discussion). Combined with quantification of the volume of colluvial fill, age-determination of the colluvium should yield data on rates of geomorphic processes.