After study, this SU is tentatively associated with a series of cuts and fills in proximity to it: SUs 334 (Fill SUs 121, 329, 332), 336 (Fill SU 335) 118 (Fills SUs 109 (packing), 119), 518 (Fill SU 517). This depression with its halo of further cuts might possibly be interpreted as a large posthole re-done many times.
Rectangular cut probably associated with the quarry's activity, because its fill was composed of a lot of quarry debris