Recent radiocarbon dating of tephra sequences and biostratigraphic analysis in the Valley of Mexico and the Valley of Puebla, respectively, reveal that the FAD (first appearance date) for lanceolate Lerma/El Jobo points at Iztapan and Hueyatlaco archeological sites at about 14–16,000 BP predates the Clovis culture FAD. A lack of interdisciplinary communication is responsible for the neglect of these sites for three decades.