Yet, if it should prove true that popcorn came to the Americas as the first form of maize, we should still have to credit the Indian with the tedious centuries—even millenniums—that went into the production of the many varieties which covered thousands of square miles of the New World when Columbus heard of “a sort of grain they call maiz.” And, before the coming of corn from Asia, we should still have to recognize the tens of centuries that went into the discovery and development of the agriculture of beans, squash, melons, potatoes, and manioc. The story of corn and of agriculture does not tell us just when early man reached our hemisphere; but it suggests that he must have settled in South America thousands of years before the birth of Christ. He needed many millenniums to evolve from a hunting and gathering savage into a farmer and to reach the cultural level at which he would develop and perfect the many varieties of corn. These millenniums may stretch back to the last interglacial—if an astounding discovery in the Valley of Mexico can be accepted. According to Mangelsdorf, a drill core from more than 200 feet below ground contained fossilized grains of pollen. Elso Barghoom has identified them as corn. The geological level where the core was taken is “probably at least 80,000 years old.”[32] 12 PUZZLES, PROBLEMS, AND HALF-ANSWERS _One swallow does not make a summer, but two lead one to suspect an abiding change in the weather._ —R. A. DALY The Pendulum Swings This chapter might have been headed “Summary.” We could not have called it “Conclusions,” for, as we read the record of early man, we saw the damage that had been done by too rash appraisals. The final pages will review the more important evidence of early man in the New World, including his relation to Old World peoples and to certain geologic phenomena. The study of early man in America has suffered from alternate spasms of unscientific enthusiasm and far too “scientific” caution. It has ranged from the parading of rumor and guesswork to the blind cranioclasm of Hrdlička. In the nineteenth century the talk was of man in the Americas before the Great Ice Age and far back into the Tertiary era that ended 1,000,000 years ago. At the beginning of the twentieth century anthropologists gave him no more than 4,000 years in the New World. Now they generally concede him 10,000 or 15,000 years, and many grant him 25,000 or more.