In this paper, are discussed the erosion, transportation and sedimentation of bed load of shallow seas or bays due to wind waves, and the amount of material eroded or deposited was estimated. In Chapter I, a consideration was made on the forces at work upon the bed load, viz. the action of gravity, the hydrodynamical upthrust and the effect of turbulence. Assuming various laws of force, the falling velocities of sand particles of different grain sizes were numerically calculated. Besides, the relation between the movement of water and that of the bed load was examined, and it was verified that large sand particles such as gravel, coarse gravel etc. cannot immediately follow the movement of the water, and are transported in the mode of sliding, rolling or saltation, while very small particles such as silt, fine sand etc. execute nearly the same motion as that of water. In Chapter II, the differential equation of erosion and sedimentation was deduced, and the solutions were obtained for some suitable boundary and initial conditions. For each solution, numerical computations were carried out. In Chapter III, the amount of material eroded or deposited was calculated. A more detailed discussion will appear in a future number of the “Geophysical Magazine”.