“…The most important geoarchaeological contribution is to bring out the importance of terrace collapse. In this respect the Tlaxcalan evidence points the same way as recent studies in the Basins of Mexico (Có rdova, 1997;Frederick, 1996) and Patzcuaro (Fisher et al, 2003, but see Metcalfe et al, 2007), the Toluca Valley (Smith et al, 2013), and the Mixteca Alta (Pé rez Rodríguez et al, 2011;Rincó n Mautner, 1999), all more densely populated than the Mezquital or Bajío that figured prominently in the debates of the 1990s.…”