The southernmost of the four zones begins on the coast of Florida,
passes for hundreds of miles over a low or gently sloping country toward
the great western plains which border the Rocky Mountains into Texas;
its southern boundary being the Gulf of Mexico. Through this region
flow numerous rivers, the queen of which is the Mississippi. The
western portion is often wild and barren in the extreme, inhabited only
by bands of wild and savage Indians. The Rocky Mountains being passed,
there is a lofty table-land, and then rise the Sierras de los Nimbres
and Madre; beyond which, bordering the Gulf of California, is the wild,
grandly picturesque province of Sonora, with its gigantic trees and
stalactite caves.