In 1876, when Patrick was making his map of the Cahokia site, he indicated that a rectangular mound with its long axis east-west stood just south of Cahokia Creek. That mound appears to have been, in Patrick’s time, very similar to but smaller than Mound 45. Mound 46 is also indicated on both the 1873 plat map for Madison County and the 1931 USGS map of the area as a slight elevation west of the railroad tracks and northwest of Mound 45. The McAdams Map shows what is probably Mound 46 as 10 feet (3.05 meters) high.
Moorehead’s maps show Mound 46 much as Patrick indicated it, no doubt because Moorehead’s map is basically a copy and revision of Patrick’s original map. However, what Moorehead did not understand was that Patrick had made a separate map of the Powell group that he did not include in the numbered mounds at the Cahokia site. Moorehead was somewhat confused in that he assumed that Mound 46 was one of the major mounds of the Powell group at the west end of the Cahokia site. With that assumption, Moorehead then added other mounds to the map to show the arrangement of mounds as he saw them at the Powell mound group. He made the main Powell Mound number 46, and the two other mounds in the group he numbered 84 and 85. The UWM Map retains Patrick’s original numbering. There are some indications of Mound 46 on aerial photos of the Cahokia site, but it does not appear as a distinct contour on the 1966 UWM Map. Mound 46 was apparently buried during construction of Interstate 55-70 and the nearby overpass over the rail road tracks. The mound protrudes slightly from the fill, as indicated by the 130-meter (426.5-foot) contour line and confirmed by inspection in the field. Thus, at least a portion of this mound is still preserved under the fill of the overpass.