Recent search around the Caspian by Huntington has disclosed the like degeneration due to encroaching desertism there. Indeed, it is no chance coincidence that just where all the great nations thrived in the morning of the historic times should be precisely where populous peoples no longer exist. For neither increasing cold nor increasing heat is responsible for this, seeing that no general change has occurred in either. Nor were they particularly exposed to extermination by northern hordes of barbarians. Egypt as a world power died a natural death, and Babylonia too; but the common people died of thirst, indirect and unconscious and not wholly of their own choosing. Prehistoric records make this conclusion doubly sure, by lengthening the limit of our observation. Both extinct flora and extinct fauna tell the same tale. In the neighborhood of Cairo petrified forests attest that Egypt was not always a wiped slate, while the unearthed animals of the Fayum bear witness to water where no water is to-day. [Illustration: PETRIFIED BRIDGE, THIRD PETRIFIED FOREST, NEAR ADAMANA, ARIZONA—PHOTOGRAPH BY HARVEY.] Anywhere we wander along these girdling belts we find the same story written for us to read. The great deserts of New Mexico and Arizona show castellated structures far beyond the means of its present Indian population to inhabit. Yet this retrenchment occurred long before the white man came with his exterminating blight on everything he touched. Nor have we reason to suppose that it arose in consequence of invasion by other alien hordes. Individual communities may thus indeed have perished as the preservation of their domiciles intact leads us to infer, but all did not thus vanish from off the Earth. Here again humanity died or moved away because nature dried the sources of its supply. And here, as elsewhere, we find prehistoric record in the rocks of a once more smiling state of things, strengthening the testimony we deduce from man. The forests, crowning now only the greater heights, are but the shrinking residues of what once clothed the land. The well-named Arid Zone is becoming more so every day.