The Tertiary-to-Quaternary Los Flores volcanic field is located in the rugged limestone peaks of the Sierra Madre Oriental at the conjunction of the states of Tamaulipas, Nuevo León, and San Luis Potosí in eastern México. Basaltic lava flows of the Mexican Basin and Range Province erupted in the valleys formed by late-Mesozoic faulting and folding that formed the NNW-SSE-trending Sierra Madre Oriental. One massive youthful, but undated Quaternary pahoehoe lava flow traveled about 80 km to the SSE down a synclinal valley from Cerro Partido.