Cumulative curves of grain-size against frequency often show segmented shapes. These shapes have been interpreted as resulting from a combination of normally distributed populations each of which should reflect a mode of transport. The present study deals with samples in motion as bedload, pure saltation load and suspended load. All of these exhibited segmented shapes on cumulative curves. An explanation of this is that the populations are better described as log-hyperbolic distributions rather than as a mixture of log-normal distributions. The log-hyperbolic distribution when plotted on probability paper has a shape which can be misinterpreted as consisting of segments.

The variation in particle size distribution for a sequence of sand samples, collected from the surface of a small barchanoid dune along a sampling line parallel to the windflow, is studied by means of the hyperbolic distribution. The modal (or typical) value of the log size increases linearly with distance from the windward foot to the crest of the dune, and falls off steeply on the lee side. The spread of the log‐size distribution, locally near the modal value, is roughly constant on the windward side but decreases significantly down the slip face. Two other parameters of the four‐parameter hyperbolic distribution can be considered largely constant. A comparison of the log size distributions for heavy and light mineral grains, based on a selected set of the samples, showed that heavy and light minerals follow different hyperbolic patterns. However, the difference in modal size of the distributions for the two types of minerals was virtually constant among the samples.

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