"From all the facts before us, we can at present say little more than this, that the valley of the Mississippi and the Atlantic coast were once densely populated by a sedentary, agricultural and partially civilized race, quite different from the modern nomadic Indians, though, possibly, the progenitors of some of the Indian tribes; and that, after many centuries of occupation, they disappeared from our country at least one thousand, perhaps many thousands of years, before the advent of the Europeans. The pre-historic remains found so abundantly in Arizona appear to be related to the civilization of Mexico; and the remains of semi-civilized Indian tribes now found there are, perhaps, descendants of the ancient builders of the great houses and cities whose ruins are found there." Researches concerning ancient mounds have been carried on in a most scientific manner by Dr. Cyrus Thomas. His chief work and research have been embodied in a monograph of over 700 pages and found the 12th Report of the government publications. Major J. W. Powell, whose studies of this subject have been considered authoritative, in his _Pre-historic Man in America_ has the following to say: "Widely scattered throughout the United States ... artificial mounds are discovered which may be enumerated by thousands and hundreds of thousands. They vary greatly in size. Some are small so that half a dozen laborers with shovels might construct one of them in a day, while others cover acres and are scores of feet in height. These mounds were observed by the early explorers and pioneers of the country.... Pseud-archeologists descanted on the Mound Builders, that once inhabited the land, and they told of swarming populations who had reached a high condition of culture, erecting temples, practicing arts in metals and using hieroglyphics.... It is enough to say that the Mound Builders were the Indian tribes discovered by the white men. It may well be that some of the mounds were erected by tribes extinct when Columbus first saw the shores, but they were kindred in culture to the peoples that still existed.... Pre-Columbian culture was indigenous, it began at the lowest stage of savagery and developed to the highest and was in many places passing into barbarism when the good queen sold her jewels."--J. W. Powell, quoted in _Larned_, Vol. I, p. 45. Thus scientists do not agree whether or not the Mound Builders were closely akin to the Indians. However recent investigators seem to agree with Thomas and Powell that the early inhabitants were much like the later denizens of the American prairies in their mode of life and means of subsistence, in their weapons, arts, usages, and customs, in their institutions and physical characteristics, they were the same people in different stages of advancement.