HANOVER, NEW HAMPSHIRE—According to a statement released by Dartmouth College, Jesse J. Casana and his colleagues spotted a large, circular earthwork near Wichita, Kansas, in thermal and multispectral imagery of the lower Walnut River Valley taken with drones. Although the area appears to be flat, Casana explained, the imagery revealed a circle-shaped ditch measuring more than 160 feet wide and six feet thick that had gradually been filled in with eroding soil. The different soil impacts the amount of water absorbed by the ditch and the type of vegetation that grows there, he added. The circle may have been a “council circle” associated with Etzanoa, home to as many as 20,000 Wichita people between 1450 and 1700. Casana and his team members speculate that the earthwork may have been visited by Spanish conquistador Juan de Oñate in 1601. To read about a pueblo in western Kansas that was built by the Taos in the 1600s, go to "Off the Grid: El Cuartelejo."