Archaeologists generally have accepted five Mexican cultures—Mayan, Zapotec, Teotihuacan, Totonac and Olmec—as being the oldest in North America, and have dated them around A.D. 300. But last week tests performed at the University of
Michigan proved that the little-known Olmec culture antedates the others by about a thousand years.
Two years ago a Smithsonian-National Geographic Society-University of California expedition excavated an Olmec ceremonial center at La Venta, a marsh-surrounded island near the Tovala River. They found among the relics several fragments of charcoal, presumably the remains of ceremonial fires. The carbon 14 content...