312 ft at the base (11 m × 83 m × 95 m). Like all of the mounds at the site where an original shape can be determined, it is a simple truncated-pyramidal platform mound. Very little excavation has taken place at this mound, so not much is known about the construction sequence or what structures may have been built upon it. There was limited work done on the mound in 1947 by John Griffin, in a salvage cleanup effort of a looters trench. He found a series of fill layers of black muck, various soil types, and caps of red clay, but as the cut was not through the entire mound or located near any structures he could not learn much about its construction sequence or definitive purpose. It was most likely the first mound started at the site, early in Fort Jacksons history. If it is similar to mounds at other sites then it was the house platform of the ruler of the site, who was also possibly a paramount chief over many other sites. Mound 3 Located across a plaza to the south of Mound 2 is Mound 3, the third-largest and third-tallest mound at the site. Mound 3 was used as a mortuary mound by its builders. At the end of its construction, it was 5 m in height and 44 by 48 m at the base (16 ft × 144 ft × 157 ft). Based on radiocarbon dating done during excavations, the mound is known to have been constructed between 760 years and 475 years Before Present (based on 1950 as present), or approximately between 1190 and 1475. Below ground level of Mound 3, was a village midden showing residential occupation at this spot before the construction of the mound began. The first activity other than village occupation is a leveling of the location and pit dug and filled with 35 stone projectile points and burned organic material. This is covered over with a layer of clay and structure erected. This building may have been used for feasting rituals. After a period of time this structure was then burned and the first of mound layer was erected over it. The first burial is included in this layer. The mound was built up in intervals, with new levels being added in stages. The bulk of the mound fill was a mixture of scraped up midden materials.