After the marks were analyzed by architectural historian/architect Mark Wenger it was determined that they were made when a rob light, or a window built into an interior wall, was installed between the studs.  Unfortunately no evidence was found that revealed the exact location for where these two studs had been initially installed.  However because these windows were very often used to supply light to stairs, it was determined to place it near the reconstructed garret stair.  Because no shelving ghosts were found on the stairs, it was decided that the most logical place to reinstall the studs that framed the rob light was on the south wall.