Nuevo Leon lies partly upon the great Mexican plateau and partly upon its eastern slopes, the Sierra Madre Oriental crossing the state N.W.
Crossing the highest part of the Mexican Plateau is a broken series of ranges, which form the water-parting between its northern and southern slopes.
The most common plants of the Mexican plateau are the agaves, yuccas and cacti, each of which is represented by a number of species.
About one thousand species have been described, a very large percentage of which are to be found on the Mexican plateau.
The mountain ranges which form part of the great Mexican Plateau consist of two marginal chains known as the Sierra Madre Occidental, on the west, the Sierra Madre Oriental, on the east, and a broken, weakly-defined chain of transverse ranges and ridges between the 18th and 10th parallels known as the Cordillera de Anahuac. All these chains are known locally under diverse names.
