As our people travel along the line of the Southern Pacific Railway, through its arid wastes of sand and sunshine, they can little realize the beautiful country of Northern Chihuahua and Sonora that lies so close to them to the southward. And yet some of this seemingly arid land in Southern New Mexico and Arizona is destined to become of far more value than its present appearance would indicate. Anglo-Saxon energy is converting little patches here and there into fertile spots, and these are constantly increasing. A great portion of the land is fine for cattle grazing, and these little oases make centers of crystallizing civilization, which render the country for miles around valuable for this important industry. The persons who believe that New Mexico will not eventually become one of the finest States in our Union belong to the class of those who put Dakota, Nebraska, and Kansas in the great American desert a decade or two ago. There is still another physical feature of at least Northern Mexico that I have never seen dwelt upon, even in the numerous physical geographies that are now extant, and it is well worth explaining. Books innumerable have spoken of the _tierra caliente_, or low, hot lands near the coast, the _tierra templada_, or temperate lands of the interior plateaus, and the _tierra fria_, or cold lands of the mountains and higher plateaus; and these subdivisions are really good as explaining Mexican climate, but they give us but little idea of the country's surface itself beyond that of altitude, and even less regarding its resources and adaptability to the wants of man. The _tierra caliente_, or hot lands of the coast, are out of the question as habitations for white men; but the _tierra templada_ and _tierra fria_, as everyone familiar with climatology knows, gives us the finest climate in the world, as do all elevated plateaus in sub-tropical countries. But these elevated plateaus, or different portions of them, are not alike in resources, and their variations are simply due to the variations in the water supply. The backbone ridge of mountains in Mexico is the Sierra Madre, or Mother Mountains, for from them all other ridges and spurs seem to emanate. From their crests, as with all other mountains in the world, spring innumerable rivulets and creeks, which, uniting, form rivers. But nearly everywhere else these streams increase in size by the addition of the waters of other tributaries until they reach the sea.