Cinder movement experiments on scoria cones slopes : Rates and direction of transport

As pan ofa field experiment to examine slope processes, four experimental grids with painted and numbered cinders were ploced on the outer crater rims of two scorio cones in the San Francisco volcanic field. Arizona. Each grid contained 50 cinders placed in five rows often each. Rows were placed parallel to local slope contours. The mean diameter for each cinder was 1.7±0.2 cm (n = 200) and the average grid slope was