AR STRACT A model of Jurassic-Cretaceous paleogeographic evolution for the northern
portion of the Mixteca terrane is presented. The interpretation is based mainly upon
stratigraphic analysis of three different areas of southern Puebla and northern Oaxaca,
where Mezosoic beds are well exposed. The oldest beds of the Mesozoic sequence
(Toarcian (?)-Aalenian) are exposed in the Tezoatlán-El Rosario area where they consist of
conglomerate sandstone, siltstone, and shale strata with some coal layers. These beds …