Abstract
A site survey was conducted in the upper drainage basin of the Rio Zahuapan in north-central Tlaxcala, Mexico, during the 1964-65 season. Sixty-three ceramic collections from 59 sites were examined and eventually seriated. The resulting sequence of pottery types indicates that, in spite of its location near major pre-Hispanic centers, this area was apparently not in the mainstream of Mexican prehistory until Late Postclassic times. Moreover, the locations and sizes of the sites sampled indicate that the area never completely lost its rural character. However, Tlaxcalan influence increased significantly with the resistance to the expansion of the empire centered at Tenochititlán and the eventual alliance with Cortes.