...Archaeologists already knew that the São Luís area, also called Upaon-Açu, meaning "big island" in the Tupí-Guaraní Indigenous languages, held traces of prehistoric human activity. For instance, a prehistoric jawbone was discovered at Farm Rosane in the 1970s and other artifacts found in São Luís have dated to 6,000 years ago, Wellington Lage, the lead archaeologist of the recent excavations, told Live Science. The remains were attributed to the Sambaquian peoples. This group relied on marine resources and built shell mounds with leftover food refuse that reached up to 100 feet (30 meters) high.The latest excavation, which began in June...