Stone Tool Analysis: Run-ons
Run-on attributes are found on the edges of flake scars. As the crack propagates through the stone, the crack’s edges follow the contours of the previous flake scars. The fracture front moves in a series of tiny ‘run-ons’ that follow up the various minute ridges and high points on the core face. These run-ons can provide the analyst with clues for determining the sequence of flake removals.
Run-on ‘tongues’ often project a short distance up ridges and high points and then terminate in steps, hinges, or feathers, and these small details can be seen under magnification. These tongue-like projections are intact on the later scar, and removed from the earlier scar. By carefully mapping out the direction of overlap indicated by run-ons, a sequence of scar removals can be reconstructed for the artefact. This sort of diacritical analysis is most suitable for fine-grained stones where run-ons are clearly expressed.