On June 11, 1999, Surface Interval Dive Company (SIDCO) conducted a gradiometer survey of a portion of the QAR site. The results of the survey are shown in this overlay map. The red areas indicate "hot spots" for ferrous objects, possibly additional cannons. The SIDCO survey area, relative to the rest of the site, is shown in the QAR June 99 Site Map. Cannon references are shown in the October 1998 map.