If my ideas as to a marked inferiority in the terra-cottas and sculptures of the Mexicans, and the very questionable proofs of their architectural achievements, are correct, they tend to confirm the inference, that not to the Aztecs, but to their more civilised Toltec predecessors, must be ascribed that remarkable astronomical knowledge in the arrangement of their calendar, which exhibits a precision in the adjustment of civil to solar time, such as only a few of the most civilised nations of the Old World had attained to at that date. But, so far as an indigenous American civilisation is concerned, it matters little whether it be ascribed to Toltec or Aztec origin. Of its existence no doubt can be entertained; and there is little more room for questioning, that among races who had carried civilisation so far, there existed the capacity for its further development, independently of all borrowed aid. The fierce Dane and Norman seemed to offer equally little promise of intellectual progress in their first encroachments on the insular Saxon. But out of such elements sprung the race which outstripped the Spaniard in making of the land of Columbus a New World; and, left to its own natural progress, the valley of Anahuac, with its mingling races, might have proved a source of intellectual life to the whole continent. But modern Mexico has displaced the ancient capital of Montezuma; cathedral, convents, and churches, have usurped the sites of Aztec teocallis; its canals have disappeared, and its famous causeways are no longer laved by the waters of the Tezcucan Lake. It is even denied by those who have personally surveyed the site, that the waters of the lake can ever have overflowed the marshes around the modern capital, or stood at a much nearer point to it than they do at present.[96] Fresh doubts seem to accumulate around its mythic story. The ruined masonry of its vanished palaces and temples may be assumed to have been all swallowed up in the edifices which combine to make of the modern capital so striking an object, amid the strange scenery of its elevated tropical valley. But Mexico was not the only city, nor even the only great capital, of the valley.