Linear cut in the bedrock running east-west from the west of wall SU541, under wall SU541 to wall SU420, underneath wall SU420 to cut SU478 in the east. Linear cut continues on the other side of SU478 (so SU564 = cut SU553 and the fill of SU564 (SU563) equals the fill of SU553 (SU552)), which cuts the two but may be related to them functionally since the depths of all three cuts are the same. Near wall SU541 the cut intersects what appears to be a natural north-south fissure in the bedrock. Depth of fissure is too deep to ascertain, but contained no anthropic material in fill.