Fragment of a head

The hundredth meridian, or a line drawn north and south near Toluca, divides ancient Mexico into an eastern half, of high civilizations in densely populated regions, and a western half, of scattered, small, and isolated tribal groupings, whose archaeological history has been recovered only in the last twenty years. In the main, this western history comprises four principal stages: (1) an early era of Olmec style which endured many centuries in Guerrero, with sporadic manifestations farther …