As cup and ring marks go these apear to be an unusual type, which I think could possibly have been the result of Neolithic axe head sharpening. Although a stone axe needs to be sharp, unlike a metal axe which has a relatively fine blade on which to create the cutting edge, the stone has to rapidly broarden and is much more curved. To sharpen it therefore it is set at a much more obtuse angle and to retain the efficiency of that greater curve it is easiest it abrade the edge in a hollow or cup. I speak from experience as a person who has shaped and sharpened stone axe heads. I found I would naturally confine my strokes to a small area and as the shape of the axe improved the area of wear on the sharpening block deepened to produce the ideal shape of the cutting edge; generally a cup or short channel is formed with the creation of each axe, and the smaller the desired tool, the smaller is the resultant depression in the block.
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