It was centuries ago--how long a time no one will ever know--when that old race was strong and numerous, filling the great region from the Rio Grande to the Colorado of the West, and from the San Juan Mountains far down into Northern Mexico. They must have numbered many hundreds of thousands, perhaps millions. It is not probable that they were combined under one government or that they were even closely leagued together, but that they were essentially one in blood and language is strongly indicated by the similarity of their remains. That they were sympathetic in a common hostility to the dangerous savage tribes about them can hardly be doubted. They were of peaceful habits and lived by agriculture, having under cultivation many thousands of acres in the rich river-bottoms, which they knew well how to irrigate from streams swollen in summer by the melting snows of the high mountain-ranges. We read of their dry canals in Arizona, so deep that a mounted horseman can hide in them. We know that they raised crops of corn and beans, and in the south cotton, which they skilfully wove. That they had commercial dealings across their whole country is shown by the quantity of shell-ornaments brought from the Pacific coast which are found in their Colorado dwellings. They did not understand the working of metals, but their implements of stone are of most excellent workmanship. Their weapons indicate the practice of hunting, and while the race was still numerous their forts and their sharp obsidian arrows made easy their resistance to the wandering savage hordes. [Illustration: RUINS AT AZTEC SPRINGS.] I believe that no instance can be cited of a people still in their Stone Age who have surpassed that old race in the mason's art: indeed, I doubt if any such people has even approached their skill in that respect. The difficulty of constructing a great work of well-squared, hammer-dressed stones is enormously increased if the masons must work only with stone implements. Imagine the infinite, toilsome patience of a people who in such a way could rear the ancient Pueblo Bonito of New Mexico, five hundred and forty feet long, three hundred and fourteen wide and four stories high! In one wall of a neighboring building of stone less carefully dressed it is estimated that there were originally no less than thirty million pieces, which were transported, fashioned and laid by men without a beast of burden or a trowel, chisel or hammer of metal.