URBANA-CHAMPAIGN, ILLINOIS—Fox News reports that Jayur Mehta of the University of Illinois and Elizabeth Chamberlain of Vanderbilt University examined Grand Caillou, a mound builder site in coastal Louisiana, through sediment coring, radiocarbon dating, optically stimulated luminescence dating, and analysis of ceramics in order to investigate how and why mound builders chose building locations. The study suggests the mound was built on a natural levee on a major lobe of the Mississippi River Delta that was a few feet higher than the surrounding landscape. Distinct layers, including clay placed at the bottom, looser sediments in the middle, and a clay cap placed on top of the mound increased its durability. Pottery at the site dates to between A.D. 1000 and 1400. The village, which supported about 500 people, had been established by about A.D. 1200. Ratios of carbon isotopes indicated saltwater incursion of the area could have led to the abandonment of the village by A.D. 1400. Many of Louisiana’s coastal mounds are now being lost to erosion. For more on mound builder sites, go to “Off the Grid: Caddo Mounds State Historic Site, Texas.”