The Mexican Plateau, in its magnificent dimensions and material wealth,
stood among the first and perhaps most alluring discoveries of European
explorers. Bur- ied deeper in the verbal histories of a now vanquished
people, the American Indians, must be the primordial human awareness of
the inverted complex triangle that dominates the Mexican topography,
climate and biota. It always has been viewed by man as a source of
wealth and a center of authority. The plateau is the pillar upon which
all Mexican conquerors have erected their capitols, tilled their crops
and mined for their treasure, and from which they dispersed the forces
of their authority. Ironically, the same size and diversity that give
the plateau its value, also make it an immense barrier. Its broad desert
and three to five thousand meter high crests constitute severe obstacles
in the path of North American man. What has just been said of mankind in
general, can be applied to the biologist in particular. He too has
termed the goliath southern plateau as the crucible of the arid biotas
of the continent (i. e., 'Madro-Tertiary'). The biologist found the
plateau to be a region of tremendous richness and diversity. But he also
has been inhibited both physically and intellectually by its high
mountain and vast desert barriers.