The formation of glacial tables is a cyclic process which when repeated indefinitely causes superglacial boulders to move across the surface of the ice in a downslope or southward (or intermediate) direction. Such "boulder migration" is independent of glacial transportation (which is the transfer of boulders due to movement of the glacier) and may take place in a totally different direction from it. Principles governing boulder migration and data bearing on the rate at which it occurs, based on studies made in 1931 on Teton Glacier, Wyoming, are summarized.