14 MEXICO AND CENTRAL AMERICA 
Tierra Templada (Temperate Land), and Tierra Fria 
(Cold Land), and in some regions each of these has an 
arid and a humid strip. The change from luxuriant 
forests to open thorny deserts is often very sudden. 
On the high plateau or Tierra Fria the natural warmth 
of the latitude is largely overcome by the altitude. In 
the Valley of Mexico snow falls only at rare intervals 
vet chilling winds are common in the winter. Much 
of the plateau from Mexico south into Guatemala is 
open farming land well suited to the raising of maize 
and wheat where water is sufficient. The shoulders of 
the mountains bear forests of pine and oak while the 
highest peaks are crowned with perpetual snow. 
A description of the mountains, rivers, and lakes will 
help towards an understanding of the problems that 
are before us. The broad plateau, crossed by irregular 
ranges of mountains, that occupies the states of New 
Mexico and Arizona continues far south into Mexico. 
On the western rim the Sierra Madre lifts a great pine- 
covered barrier, beyond which the land drops off 
quickly into the hot fringe of coastal plain bordering 
the Pacific Ocean and the Gulf of California. The 
highest mountains of the western Sierra Madre are El 
Nevado and Colima, the first a snowy peak 14,370 feet 
high and the second an active voleano 12,278 feet high. 
On the western rim of the central plateau the second 
Sierra Madre is less continuous but it culminates in the 
loftiest peak of all Mexico—the wonderful cone of 
Orizaba. This mountain rises from the tropical jungles 
well into the region of perpetual snow and attains an 
elevation of 18,314 feet above the sea. Its name in 
Aztecan is Citlaltepetl, which means Star Mountain. 
Two other famous peaks of Mexico are Popocatepetl 
and Iztacchihuitl, both names being pure Aztecan. 
The first means Smoking Mountain and the second 
