Additionally, to the northwest of the stockaded area, a row of round mounds extends northward. When archaeologists excavated in these mounds during the 1920s, they did not find the burial sites they had expected. Instead, each mound had a large post set in a pit in its center, surrounded by gravel and soil, with the pit capped with clay and gravel to hold the post steady. These mounds have been termed "marker mounds" because they may have been used to mark the site for travelers, but this is not certain. They may also have been used for announcements, message relays, or for calculations of astronomical phenomena, as has been found at other Mississippian sites, such as Cahokia.