142 A SYNOPSIS OF THE INDIAN TRIBES. [iNTROD. The chain of mountains, east of Lake Timpanogo, and west of the Rio Colorado, continues southwardly, close to that river, to the thirty -sixth degree of latitude, where it terminates. The chain which divides the waters of the Rio Norte, from those of the Arkansa, is well known, and is an easterly branch of the Rocky Mountains. But the main chain, which may be consid- ered as a continuation of the Mexican Andes, lies between the Colorado and the Rio Norte. This section of the country is known to us only through the reports of our beaver-hunters (dappers), who have not penetrated farther south than the thirty-seventh degree of latitude. They represent the country extending thence northwardly to the sources of the river Platte, as being only a body of mountains, intersected at right angles by rivers that empty into the Colorado. The only section, which has not at all been explored by the Americans, is that lying east of the Colorado between the Rio Gila and the thirty- seventh decree of north latitude. The uniformity of character in the grammatical forms and structure of all the Indian Languages of North America, which have been sufficiently investigated, indicates a common origin. The numerous distinct languages, if we attend only to the vocabularies between which every trace of affinity has disap- peared, attest the antiquity of the American population. This may be easily accounted for, consistently with the opinion that the first inhabitants came from Asia, and with the Mosaic chronology. The much greater facility of communication, either across Behring's Straits, or from Kamschatka or Japan by the Aleutian Islands, w 7 ould alone, if sustained by a similarity of the physical type of man, render the opinion of an Asiatic origin, not only probable, but almost certain. The rapidity with which the human species may be propagated under favorable circumstances removes any apparent inconsistency between that opinion and the early epoch, which must be assigned to the first appearance of man in America. Reasoning a priori, it would appear that the population of a country may be doubled in the short period of fifteen years, provided it finds adequate means of subsistence. We know with certainty, that the white inhabitants of the United States continue even now to increase, independent of migration, at the rate of near thirty-three and a third per cent, in ten years, and
