Notwithstanding the convenience of deferring the more general discussion of the question until the Peruvians--indeed, until the whole of the American tribes have been considered--the present is, nevertheless, a convenient time for taking in, by means of a retrospect, some of the more material facts connected with the social and civilizational capacity of the Indians which have last been described--_i.e._ the _non_-Eskimo tribes of the parts between the Rocky Mountains and the Paducas. This is to be measured by what is called the Indian biography of their men of mark like Thyandeeeya (Brandt), Tecumseh, or Powhattan, by the history of the Indian wars and confederations, and, better still, by an exponent which, because it has a special application upon the problems last indicated, will find a place amongst our present investigations--their architectural archæology. The Trustees of the Smithsonian Contributions to Knowledge have broken ground with the publication of a careful, elaborate, and critical description of the ancient monuments of the Mississippi Valley, the result of original surveys and explorations, by Mr. Squier and Dr. Davis; and it is only the contemporary publication of the Ethnology and Philology of the United States Exploring Expedition, that makes this the _second_ of the great contributions to ethnological science, which have been supplied by the same country within the same year. And first, as to the area over which these remains are spread.--West of the Rocky Mountains,[136] the most that has hitherto been found is a few mounds, _tumuli_, or barrows. They will be called _mounds_. North, too, of the Great Lakes, the remains are but few, and imperfectly described. On Lake Pepin, on Lake Travers (in 46° N.L.), we find notices of them; so we do for the Missouri, as much as 1000 miles above its junction with the Mississippi. Eastward, they decrease as we approach the Atlantic; _i.e._ on the Atlantic aspects of Pennsylvania, New York, and Virginia, they become scarcer. They become scarce, too, on the other side of the River Sabine; not that they are wanting in Texas, but that they either fall off in number or change in character as we approach Mexico. The great centre of their development is the vast valley of the Mississippi, and amongst the valleys of its feeders--that of the Ohio preeminently. Here the accumulation is at its _maximum_. In Ross country alone, 100 enclosures and 500 mounds have been noticed; whilst the whole amount for the state of Ohio has been reckoned at 10,000 of the former, and 1,000 or 1,500 of the latter. [Illustration]