Amidst the plains of North America, some powerful nation, which has disappeared, constructed circular, square, and octagonal fortifications; walls six thousand toises in length; tumuli from seven to eight hundred feet in diameter, and one hundred and forty feet in height, sometimes round, sometimes with several stories and containing thousands of skeletons. These skeletons are the remains of men less slender and more squat than the present inhabitants of those countries. Other bones wrapped in fabrics resembling those of the Sandwich and Feejee Islands are found in the natural grottoes of Kentucky. What is become of those nations of Louisiana anterior to the Lenni-Lenapes, the Shawanese, and perhaps even to the Sioux (Nadowesses, Nahcotas) of the Missouri, who are strongly mongolised; and who, it is believed, according to their own traditions, came from the coast of Asia? In the plains of South America we find only a very few hillocks of that kind called cerros hechos a mano;* (* Hills made by the hand, or artificial hills.) and nowhere any works of fortification analogous to those of the Ohio. However, on a vast space of ground, at the Lower Orinoco, as well as on the banks of the Cassiquiare and between the sources of the Essequibo and the Rio Branco, there are rocks of granite covered with symbolic figures. These sculptures denote that the extinct generations belonged to nations different from those which now inhabit the same regions. There seems to be no connection between the history of Mexico and that of Cundinamarca and of Peru; but in the plains of the east a warlike and long-dominant nation betrays in its features and its physical constitution traces of a foreign origin. The Caribs preserve traditions that seem to indicate ancient communications between North and South America. Such a phenomenon deserves particular attention. If it be true that savages are for the most part degenerate races, remnants escaped from a common wreck, as their languages, their cosmogonic fables, and numerous other indications seem to prove, it becomes doubly important to examine the course by which these remnants have been driven from one hemisphere to the other.