Considered geographically, Mexico is, in the main, an immense table-land or plateau, which seems to be a flattening out of the Rocky and Sierra Nevada Mountains, and which, commencing within the territory of the United States as far north certainly as Central Colorado, and perhaps beyond, extends as far south as the Isthmus of Tehuantepec; a north and south length, measuring from the southern frontier-line of the United States, of about two thousand miles. Entering the country by the "Mexican Central Railway" at El Paso, where the plateau has already an elevation of 3,717 feet, the traveler progressively and rapidly ascends, though so gradually that, except for a détour, made obligatory in the construction of the road to climb up into the city of Zacatecas, he is hardly conscious of it, until, at a point known as Marquez, 1,148 miles from the starting-point and 76 miles from the city of Mexico, the railroad-track attains an elevation of 8,134 feet, or 1,849 higher than the summit of Mount Washington. In fact, as Humboldt, as far back as 1803, pointed out, so regular is the great plateau on the line followed by the "Central" road, and so gentle are its surface slopes where depressions occur, that the journey from the city of Mexico to Santa Fé, in New Mexico, might be performed in a four-wheeled vehicle.
From Marquez, or the railroad "summit," the
