There was no single birthplace of American culture. Advance took place wherever the climate was mild and the soil fertile, and thus an abundant supply of food could be obtained. One such locality was the valley of the San Juan, in what is now the southwestern part of the United States. It is quite allowable to suppose that here the mild climate and bountiful soil suggested agriculture, and with a knowledge of this, rude though it was, a beginning was made in a culture which subsequently excited the admiration of the Spaniards. However that may be, we know this section contains abundant ruins of former inhabitants. And yet again we find in this same country the remnants of this former people, doubtless living much the same sort of life as did their forefathers. American scholars, with the best of reason, think this section affords the best vantage ground from which to study the question of native American culture. It presents us not only with ruins of past greatness, but in the inhabited pueblos, gives us a picture of primitive times, and invites us, by a careful study of their institutions, to become acquainted with primitive society. Travelers and explorers describe the scenery of the Pueblo country as a very peculiar one. It is bleak without being absolutely barren. The great mountain chains form picturesque profiles, which in a measure compensate for the lack of vegetation. No country on the face of the globe bears such testimony to the power of running water to wear away the surface. The rivers commenced by wearing down great cañons. They occur here on a grand scale. The cañon of the Colorado River, having a length of two hundred miles, and through the whole, nearly vertical walls of rock, three to six thousand feet in height. Nearly all the tributary streams of the Colorado empty into it by means of gorges nearly as profound. What is true of the Colorado is true, though in a lesser degree of the Rio Grande and of the Pecos, as only portions of these streams are cañon-born. But, besides digging out these cañons, the entire surface of the country has in places been removed to the depth of several hundred feet, leaving large extent of table-lands, called mesas, with generally steep, or even precipitous, sides, standing isolated here and there.