30 Oeograpbicai iRotes on flDejico, 



one hundred miles from the coast, leaving an imperceptibly inclined 

 plane from the sea to the foot of the mountains ; while the cordillera 

 on the Pacific side runs, on the whole, very near the coast, leaving a 

 very narrow strip of land between the same and the sea, and from this 

 run several branches in different directions. The most continuous 

 range is the Sierra Madre of the Pacific, which may be traced, at a 

 mean elevation of over 10,000 feet, from Oaxaca to Arizona. Parallel 

 to this is the Lower Californian range (Sierra de la Giganta) 3000 

 feet, which, however, falls abruptly eastwards, like the Atlantic escarp- 

 ments. The California peninsula seems to have been detached from 

 the mainland when the general upheaval took place which produced 

 the vast chasm now flooded by the Gulf of California. Corresponding 

 with the Sierra Madre on the west are the more interrupted eastern 

 scarps of the central plateau, which sweep around the Gulf of Mexico 

 as the Sierra Madres of Nuevo Leon and Tamaulipas at an elevation 

 of about 6000 feet. These are crossed by the routes from Tula to 

 Tampico, the highest pass being 4820 feet ; from Saltillo to Monterey 

 3400, and at several other places. 



Of the central cross ridges the most important orographically and 

 historically is the Cordillera de Anahuac, which surrounds the Mexi- 

 can (Tenochtitlan) and Puebla valleys, and which is supposed to cul- 

 minate with Popocatepetl and Ixtacihuatl. But these giants belong to 

 a different or rather more recent system of igneous upheaval, running 

 from sea to sea between 18 59' and 19 12' N. in almost a straight line 

 east and west, consequently nearly at right angles to the main axis of 

 the central plateau. The line is clearly marked by several extinct 

 cones and by five active or quiescent volcanoes, of which the highest 

 is Popocatepetl, lying south of the capital, nearly midway between 

 the Pacific and the Atlantic. East of the central point of the system 

 are Citlaltepetl, better known as the peak of Orizaba, on the coast 

 south of Veracruz, to which correspond on the west the recently 

 upheaved Jorullo in Michoacan, Colima (12,800) near the coast in 

 Jalisco, and the volcanic Revillagigedo group in the Pacific. South 

 of this line and nearly parallel, are the sierras of Guerrero, and south- 

 east of the Tehuantepec Isthmus those of Oaxaca and Chiapas towards 

 the Guatemala frontier. In the same direction run the islands of Cuba 

 and Hayti, which probably belong to the same Central American system. 



In the course of centuries these high mountains have become dis- 

 integrated by the rains and other natural elements, and a great many 

 spaces between them filled up, forming a series of valleys and other 

 spots quite delightful in climate and very rich in agricultural resources. 

 This series of valleys, which we call the central plateau, runs from 

 about one hundred and fifty miles east of the City of Mexico, travers- 

 ing all of Mexico in a northwesterly direction. So level is the plateau 



