This SU contains two fistulae, which would have been part of an earlier drainage system in room G-20. It is unclear whether this SU is in a primary or secondary deposition. It seems to me more likely to be a primary deposition due to its proximity to and alignment along rock 6241 that suggests it was placed there, the obscured northern limit that could run below wall 6242, and the alignment perpendicular to 6242 facing the road, where we know there was a drainage system.