There are two big mountain ranges crossing Mexico North-South. That probably kept some of the indigenous groups isolated from each other for a long time. There

There are two big mountain ranges crossing Mexico North-South. That probably kept some of the indigenous groups isolated from each other for a long time. There is also the division between Mesoamerica (South) and Aridoamerica(North). Two different sets of cultures that needed different technologies. Settlers and Nomads.