After study, this cut is associated with a number of round pits located in the central part of area A which may have accommodated the posts to which cranes’ tie-rods were tied.
This small circular cut in the bedrock may have been a posthole. The slight undercutting on the southwest part/side appears to be erosion rather than an intentional cut. The evident erosion may indicate that the cut was left empty & exposed to erosion for a period.