culminating in the crests
of these mountains which enclose the great plateau on both sides.

[Illustration: ASCENDING THE MEXICAN CORDILLERA, OR EASTERN SIERRA
MADRE: THE RAILWAY IS SEEN IN THE VALLEY FAR BELOW.]

The Sierra Madres, or Mexican Andes, have the general Andine direction
of north-north-west. They are divided into two systems--the western and
the eastern--whose respective crests in the north are from 400 to 500
miles apart, enclosing the _mesa central_, and which approach towards
the south. The Pacific range has some important ramifications from its
main system, but the general Andine structure is maintained. The range
is again encountered in the long peninsula of North-Western
Mexico--known as Lower California--where it parallels the eastern side
of this great tongue of land for more than 700 miles. Indeed, a study
of Mexico's orography and the delineation upon the map shows the series
of parallel features formed by alternate mountain-folds and intervening
basins--the peninsula of Lower California; the Gulf of the same name;
the Western Sierra Madre; the intersecting crests of the great plateau;
the Eastern Sierra Madre, and the Gulf Coast. Thus these huge
"earth-wrinkles" of the Andine system of South America show their
characteristics in Mexico, modified, however, by cross-agencies of
volcanic nature. The map of Mexico shows strikingly how the country is
formed upon its rocky framework, the ribs of these vast folds.

[Illustration: THE STATE OF VERA CRUZ: THE PEAK OF ORIZABA; PLAZA OF
THE CITY OF CORDOVA.]

The passes over these mountain ranges, giving access to the
plateau-interior of Mexico from the oceans, vary from 8,500 feet to
10,000 feet, the range upon the Pacific side being generally the
higher. But the highest peaks rise much above these altitudes, in some
few cases reaching beyond the perpetual snow-line, although ever much
lower than the Andes of South America. Three culminating peaks only
pass the snow-line in Mexico, although others of the crests and summits
are frequently snow-covered. The first of these three peaks is Orizaba,
or Citlaltepetl--the "Star Mountain" of the native--the beautiful and
symmetrically formed cone whose gleaming snow-cap is seen by the
approaching traveller far over the stormy waters of the Gulf as he
approaches the shores of Vera Cruz. So Grijalva and Cortes saw it; so
the voyager of to-day sees it, as its snowy point seems to hang in
mid-sky, its base buried