Burial of transported material in gravel bed rivers was examined using several hundred magnetically tagged particles. Burial depth of individual particles varies with no simple relation to particle size. Distributions of burial depth of particles were examined by considering observed burial depth of individual size groups of all mobile particles and of all tagged particles (including static ones). ''Simple'' (single-peak) flow events yielded exponential distributions of burial depth of mobile particles. Distributions with secondary peaks were obtained from large and multipeak events. Season long results were skew peaked with a tendency toward uniformity. An m-layer model is developed to account for the variation of frequency of burial depth of particles, based on the assumptions that the burial depth of particles in a simple event is exponentially distributed and the proportion of particles which change vertical position from a given layer is constant from event to event. The model is elaborated for varying mixing rates, varying scour depths, and variable behavior of different size classes. After many events the material is uniformly distributed throughout all layers, in conformity with field experience.